Thermal Comfort Challenges in Home-Based Enterprises: A Field Study from Surakarta’s Urban Low-Cost Housing in a Tropical Climate

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper is an interesting study, presenting an investigation into indoor thermal conditions in home-based enterprises (HBEs) within the informal urban settlements of Surakarta City, Indonesia. The study is an original work with extensive literature review and comprehensive analyses providing new contributions to the body of knowledge in the associated field, especially in the particular context. No further comments.

1.  The main question addressed by this research is the thermal comfort challenges in home-based enterprises; in this case through a field study from Surakarta’s urban low-cost housings in a tropical climate in an Indonesian city.

2. The topic is somewhat original (in particular to the studied context) and definitely relevant in the associated field. Yes, it does address specific gaps in the related field and is a needed research in the same context.

3. This manuscript is sharing a particular study from a particular context, from Surakarta’s urban low-cost housing case study in a tropical climate in an Indonesian city, focusing on thermal comfort challenges experienced. This is an important contribution to the body of knowledge to in the associated field.

4. In my opinion, this is a complete work and the authors have already sufficiently covered all required aspects for any high-standard research paper, and therefore it is satisfactory in its current form

5. The conclusions are consistent with the evidence and arguments presented and they addressed the main question posed (even the research question is not very clear).

6. The references are very clear.

7. The tables and figures are clear and appropriate.

Author Response

Response to Reviewer: 1

 

I, along with my co-authors, would like to express our appreciation to your comments on our paper titled “Thermal Comfort Challenges in Home-Based Enterprises: A Field Study from Surakarta’s Urban Low-Cost Housings in a Tropical Climate”. The comments have helped us improve the manuscript. According to your comments and suggestions, we have revised the manuscript. We highlighted the newly added or modified parts by red color, and blue font indicates the sentences moved to the different subsection for improving the readability and logical flow.

 

(1) The main question addressed by this research is the thermal comfort challenges in home-based enterprises; in this case through a field study from Surakarta’s urban low-cost housings in a tropical climate in an Indonesian city.

Thank you for your positive feedback

 

(2) The topic is somewhat original (in particular to the studied context) and definitely relevant in the associated field. Yes, it does address specific gaps in the related field and is a needed research in the same context.

Thank you for your positive feedback

 

(3) This manuscript is sharing a particular study from a particular context, from Surakarta’s urban low-cost housing case study in a tropical climate in an Indonesian city, focusing on thermal comfort challenges experienced. This is an important contribution to the body of knowledge to in the associated field.

Thank you for your positive feedback

 

(4) In my opinion, this is a complete work and the authors have already sufficiently covered all required aspects for any high-standard research paper, and therefore it is satisfactory in its current form

Thank you for your positive feedback

 

(5) The conclusions are consistent with the evidence and arguments presented and they addressed the main question posed (even the research question is not very clear).

Thank you for your positive feedback

 

(6) The references are very clear

Thank you for your positive feedback

 

(7) The tables and figures are clear and appropriate

Thank you for your positive feedback

 

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The article identifies technical problems related to maintaining thermal comfort. The discussed issues are extremely important. The references used in the article are relevant and provide a good introduction to the topic.

The article is suitable for publication, but requires the following clarifications and improvements:

1. A lot of information has been collected, but there is a lack of clearly defined evaluation criteria. A qualitative description can be found in the conclusions, but it is very briefly. An extended discussion of the results is necessary.

2. In Figure 4, only one District is correctly shown.

3. Figures that contain two or more elements (e.g., Figures 4 and 5) should be labeled with letters "a)", "b)", etc. The captions for the figures should clearly describe what they refer to.

Comments on the Quality of English Language

A careful language correction is required, as well as attention to the quality of the presented dat.

Author Response

Response to Reviewer: 2

 

I, along with my co-authors, would like to express our appreciation to your comments on our paper titled “Thermal Comfort Challenges in Home-Based Enterprises: A Field Study from Surakarta’s Urban Low-Cost Housings in a Tropical Climate”. The comments have helped us improve the manuscript. According to your comments and suggestions, we have revised the manuscript.

 

(1) A lot of information has been collected, but there is a lack of clearly defined evaluation criteria. A qualitative description can be found in the conclusions, but it is very briefly. An extended discussion of the results is necessary.

 

Thank you for the suggestion. To respond your comment, we thoroughly improved the description about the discussion and conclusion as below. Red part is newly added to enrich the discussion.

 

Section 3.1: last paragraph

All the findings derived from three metrics suggest that the HBE spaces of these dwellings do not meet the thermal comfort criteria as working environments, and highlight the necessity of improvement by affordable measures.

 

Section 3.4: first paragraph

Table 4 presents the building design features critically affecting natural ventilation effectiveness and the indoor thermal environment. Notably, 10 of the 12 dwellings surveyed are semi-detached or terraced, sharing two or three external walls with neighboring buildings. This configuration limits the availability of windows and other openings. This setup is especially common in the six dwellings within Districts M, H, and T, which were designed as part of a slum upgrading initiative and are constrained by limited land availability. In particular, dwelling M2 is enclosed by three other dwellings, with only the entrance side wall exposed to the outside air. As a basic design policy for housing complexes in urban slum upgrading projects, each unit should be designed to face at least two sides to the outside air, regardless of land constraints. In contrast, dwellings S1 and S6 stand as detached houses, fully independent and with ample surrounding space—a rarity within the densely constructed District S.

 

Section 3.4: third paragraph

Dwelling S6, benefiting from a larger site with vacant surrounding land, nonetheless exhibits limited cross-ventilation potential due to minimal windows or openings on the far end and sides of external walls, as seen from the entrance (Figure 6(a)). As a result, the living room, kitchen, and bedroom have no windows. Additionally, as shown in Figure 8, even in the HBE space with openings in two locations, a large number of products are stacked from floor to ceiling in the extremely narrow store interior, causing poor air circulation. Such a design flaw, despite ample space with adequate privacy, might be attributed to incremental, low-cost renovations by residents without professional architectural input. This issue, alongside other floor plans detailed in Appendix Figure A1, underscores that challenges in achieving effective cross-ventilation stem not only from site constraints but also from a lack of awareness among residents and local builders about the critical need for strategic opening design.

 

Section 3.5: last two paragraphs

Lastly, despite the daily habit of introducing outside air by opening windows and doors, and an apparent understanding of the benefits of natural ventilation among residents, cross ventilation is notably absent in the building designs, as shown in Table 4. The majority of the surveyed dwellings, whether in kampung areas or urban slum upgrading projects, are constructed incrementally. Residents modify the interiors, exteriors, or openings of their homes based on their preferences, needs, and financial capabilities. However, securing openings or installing exhaust fans for ventilation does not appear to be a commonly considered option.

To improve the current situation, it is important to provide not only financial support but also knowledge support. This includes sharing specific methods to enhance natural ventilation, such as determining the size and position of openings, designing layouts, and other techniques with community members and small local construction businesses involved in the building process.

 

Section 4

 

HBEs are prevalent in urban informal settlements and play a crucial role in the economies of low-income households across many developing countries. Such settings often suffer from poor infrastructure and substandard living conditions, rendering them susceptible to environmental stressors, including high temperatures and indoor air pollution. Our study employed a multimodal approach, incorporating field measurements, architectural observations, and interviews within twelve dwellings in Surakarta City, Indonesia. We aimed to explore the current conditions and challenges faced by individuals operating HBEs, with a specific focus on achieving thermal comfort indoors. Additionally, we thoroughly investigated common architectural design issues through our field surveys. Key findings from this study include:

• Thermal measurements inside six dwellings revealed temperatures exceeding 30°C for 50-60% of working hours. This indicates a breach of acceptable thermal comfort standards and highlights the necessity for improvement in working conditions.
• Due to limited available land, the floor area per occupant varied between 8.6 to 13 m² in most of the dwellings studied. Additionally, most dwellings shared two or three exterior walls with adjacent buildings. These densely populated conditions resulted in limited openings and significantly hampered cross-ventilation. Nine surveyed homes even had bedrooms without windows.
• Certain types of HBE activities, notably ironing and cooking, generated significant heat and water vapor indoors over extended periods. Despite this, none of the homes featured mechanical ventilation systems; reliance was solely on natural ventilation through open windows and doors.
• To maximize comfort under severe constraints, residents typically opened windows and doors to introduce outside air and conducted HBE activities in larger spaces with multiple openings. Despite these routine habits, there is a lack of effective building design to ensure cross-ventilation. In the surveyed dwellings that were incrementally modified, creating openings or installing exhaust fans for ventilation does not seem to be a commonly considered option.

 

Overall, this research has illuminated the pressing issue of hot and inadequate working conditions for HBE workers living in low-cost dwellings in Surakarta City, Indonesia. The findings underscore the urgent need for better architectural strategies and facilities that are applicable for both urban-slum upgrading projects and the incremental construction of existing slum housing. Although there are challenges posed by economic constraints, the following actions are specifically recommended:

• In the context of urban-slum upgrading projects, it is imperative to ensure cross-ventilation. This can be achieved by designing layouts where at least two sides of each building do not share walls with adjacent structures, thereby incorporating openings that face the external environment.
• It is essential to enhance the understanding of both residents and local construction workers regarding the importance of installing windows in appropriate positions and sizes. This knowledge can then be applied in the incremental renovation practices within the urban informal settlements and upgraded ones. To achieve this, advice and enlightenment from experts such as scholars and architects for the communities would be effective.

 

Our study offers valuable insights. However, the relatively small sample size could limit the robustness of our conclusions. Additionally, the study is geographically confined to Surakarta City and may not be directly applicable to other cities in Indonesia. In light of these findings, future research should explore the following points:

• Ventilation-Related Design Parameters: Incrementally constructed low-cost dwellings are highly diverse, with numerous design variables affecting the indoor thermal environment. Future studies should focus on cross-ventilation factors, such as windowless rooms. Conducting field surveys on a larger number of samples will clarify the background and influencing factors that lead to flawed designs.
• Design Guidelines Development: For urban-slum upgrading projects, it is crucial to develop design guidelines for low-rise housing. Recent studies have optimized building passive design for indoor thermal comfort and energy savings using surrogate-assisted models under various contexts [50]. Research using these methods will be advantageous in exploring appropriate designs that consider ventilation, lighting, and functionality within economic and land constraints.
• Surveying Strategies: In urban-slum upgrading projects across various Indonesian cities, particularly for constructing low-rise housing, it is important to survey the strategies employed by relevant sectors at all stages of planning, design, construction, and renovations by residents. These surveys will help identify ways to convey academic knowledge to stakeholders, ensuring better housing designs.

(2) In Figure 4, only one District is correctly shown.

We apologize for the inappropriate layout of the figures of the previous manuscript. We certainly corrected this problem as below.

Figure 4 Appearance of Survey District

 

 

(3) Figures that contain two or more elements (e.g., Figures 4 and 5) should be labeled with letters "a)", "b)", etc. The captions for the figures should clearly describe what they refer to

 

We are highly appreciating your detail correction. We improved the caption of the figures and added the branch number for each figure. We adopted the style of branch number: (a), (b), (c) rather than a), b), c) according to the MDPI template. The revised parts are shown below.

Figure 5. (a) Averaged daily fluctuation of operative temperature and (b) PMV at six dwellings of district S during HBE working hours

Figure 6.  (a) Cumulative probability density distributions of operative temperatures and (b) PPD at six dwellings of District S during HBE working hours

 

 

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

1. Clarify Research Objectives and Hypotheses:

o Please provide a detailed exposition of the primary objectives and hypotheses of the study in the introduction. Ensure that these objectives and hypotheses are closely connected to the research methods, results, and discussion sections, offering readers a clear roadmap of the research.

2. Expand the Scope of Literature Review:

o It is recommended to include more research on indoor thermal comfort in tropical climates and studies related to the living and working conditions of Home-Based Enterprises (HBEs) in the literature review. This will provide a more solid theoretical and empirical foundation for the study.

3. Enhance the Transparency of Methodology:

o Please offer a comprehensive description of the research methodology, specifying the criteria for sample selection, detailed steps for data collection, and the methods of analysis. This will enhance the reproducibility of the study and the credibility of its methodology.

4. Deepen the Discussion Section:

o The discussion section should further explore the socio-economic factors behind residents' behaviors that affect the indoor thermal environment. This will contribute to a more comprehensive understanding of the study's results and provide deeper insights for the formulation of relevant policies and measures.

5. Clarify Conclusion Content:

o The conclusion section should clearly reflect the main findings of the paper and point out the limitations of the study. Additionally, suggest directions for future research to provide guidance for subsequent investigators.

6.As a scientific paper, the layout and display of figures and tables require further improvement.

Comments on the Quality of English Language

Minor editing of English language required

Author Response

Response to Reviewer: 3

 

I, along with my co-authors, would like to express our appreciation to your comments on our paper titled “Thermal Comfort Challenges in Home-Based Enterprises: A Field Study from Surakarta’s Urban Low-Cost Housings in a Tropical Climate”. The comments have helped us improve the manuscript. According to your comments and suggestions, we have thoroughly revised the manuscript. In the below responses, we highlighted the newly added or modified parts by red colour.

 

(1) Please provide a detailed exposition of the primary objectives and hypotheses of the study in the introduction. Ensure that these objectives and hypotheses are closely connected to the research methods, results, and discussion sections, offering readers a clear roadmap of the research.

 

Thank you for your valuable suggestion. Since this paper is an exploratory study rather than a hypothesis-testing study, no clear hypotheses were set prior to the investigation. Instead, research questions were established to be clarified through the exploratory investigation of HBE housing.

As you pointed out, the descriptions in the previous manuscript were unclear in this regard. Taking your comments into account, we have revised the introduction as follows:

 

Section 1, line 139

With this background, the present study aims to address the research gap concerning indoor thermal conditions experienced by home-based workers in substandard HBE housing in Indonesia. By focusing on homes with varied HBE functions in Surakarta, Central Java, we explore three key research questions using both qualitative and quantitative approaches:

1) To what extent do the indoor climate conditions of HBE housing meet thermal comfort criteria as a working environment?

2) What problems exist in the design of HBE housing regarding the maintenance of good indoor air quality and thermal comfort?

3) What types of adaptation strategies have home-workers employed to improve their environmental conditions in their current HBE housing, given economic constraints?

Specifically, we investigated HBE housing in four residential areas within the city of Surakarta. One area is an urban slum known as kampung, while the other three are newly constructed low-rise residential districts planned to eliminate urban slums. We conducted in-depth interviews with residents and on-site observations in twelve dwellings across these districts to grasp the characteristics of housing design and occupants’ behaviors related to the indoor thermal comfort of home workers. For six of these dwellings, we estimated the time-series thermal comfort index during working hours using existing indoor thermal environment data and evaluated the fraction of thermal discomfort hours [42][43]. In fact, these simulations have been used to explore passive cooling designs effective in improving the indoor thermal environment of tropical residences [44]. Overall, this study aims to contribute to the development of environmental improvement measures for HBE housing within Indonesia’s urban informal residential areas.

 

 

With this revision, we believe that the relationship among the research objectives, research methods, and findings has become more closely connected, resulting in a better logical flow in the revised manuscript.

 

 

(2) It is recommended to include more research on indoor thermal comfort in tropical climates and studies related to the living and working conditions of Home-Based Enterprises (HBEs) in the literature review. This will provide a more solid theoretical and empirical foundation for the study.

 

We appreciate your valuable suggestion. We thoroughly surveyed the past studies, and reorganized the majority of the introduction section as below.

 

Section 1, line 45: research on indoor thermal condition of housing at hot climate zone

With such a background, the indoor thermal conditions of naturally-ventilated residential buildings in South-East Asia and other developing regions with hot climates have been extensively investigated, focusing on occupants' thermal comfort, health, and living quality. For example, Kubota et al. [9] conducted a field experiment in typical terrace houses to examine the effectiveness of ventilation as a passive cooling method. They found that night ventilation improves thermal comfort but also emphasized the need for indoor humidity control during the daytime. Toe and Kubota [10] measured indoor thermal conditions in traditional Malay houses in Malaysia under natural ventilation and revealed that indoor air temperatures were generally higher than outdoor temperatures, underscoring the importance of passive cooling techniques. Djamila and Kumaresan [11] conducted a field survey of indoor thermal comfort among 890 occupants and assessed physical indoor thermal variables in non-air-conditioned residences in Kota Kinabalu, Malaysia. They suggested that high indoor temperatures necessitate passive cooling strategies in building designs. Irakoze and Kim [12] evaluated the indoor thermal conditions of three main urban housing types—informal settlements, planned low-income housing, and modern urban housing—in Kigali, Rwanda, located in a tropical highland climate zone, using building energy simulations. Naicker and Mathee [13] reported high heat risk based on indoor temperature measurements in 100 low-cost houses in South Africa.

 

Section 1, from line 79: research on indoor thermal condition of Indonesian housing

For instance, a study conducted by Murtyas et al. [18] involved field measurements of the indoor thermal conditions in 17 urban slum dwellings in Surakarta, Indonesia. Their findings revealed that the majority of these houses failed to meet the thermal comfort criteria established by ASHRAE55-2017 for most hours, resulting in a high risk of heatstroke. Based on the measured data from this study, Murtyas et al. [19] also reported a high mould risk in low-cost housing due to high humidity and poor ventilation. Hildebrandt et al. [20] investigated the indoor air quality and health conditions of occupants in newly constructed high-rise apartments and traditional kampung houses in Surabaya. They found that while high-rise apartments had higher levels of formaldehyde and total volatile organic compounds, mould issues were more severe in kampung housing due to higher humidity and poor ventilation. Similarly, Hanief et al. [21] reported field measurements of indoor air quality and humidity in informal settlements in Bandung, Indonesia, highlighted the elevated mold risk associated with low construction quality and the hot, humid climate. Furthermore, Prihardanu et al. [22] reviewed recent field studies on indoor air quality of housing and relevant national regulations and standards, suggesting inadequate ventilation in housing and gaps in the implementation of mandatory regulations.

 

 

Section 1, line 95: research on home-based workers in developing countries

Meanwhile, several studies have indicated that a significant proportion of residents in informal settlements in developing countries are engaged in home-based work, one of the three typical urban informal occupational groups alongside street vendors and waste pickers [23,24]. Home-based workers, particularly those who are self-employed or sub-contracted, often find themselves more vulnerable to the influence of the macroeconomic environment [25]. Furthermore, they are exposed to substandard indoor working conditions due to low-quality housing [26] and hazardous pollutants from the indoor manufacturing activities [27]. In 2006, Tipple [28] reported the results of surveys of home-based enterprise (HBE) households in Cochabamba, Bolivia; New Delhi, India; Surabaya, Indonesia; and Pretoria, South Africa, highlighting their poor working conditions and various health risks. Almost 20 years after the publication of this paper, working and living conditions in HBE continue to be a problem in many developing countries.

 

Section 1, from line 115: research on design and planning of HBE housing in Indonesia

The integration of HBEs in small low-cost housing in Indonesia presents unique features of adaptive space usage, as explored by several key studies. Sihombing [36,37] reported that the architecture of kampung houses often evolves to incorporate in-house businesses, such as “warung” (small stalls), laundry services, food shops, and other commercial ventures to meet local demands. Spaces within HBE dwellings are notably flexible; serving multiple purposes—ranging from a workspace to a living room—depending on the time of day. Prakoso and Dewi [38] highlighted the use of flexible spaces to reduce conflicts between living and working areas. Suparwoko and Raharjo [39] examined the blend of local and western influences in Yogyakarta HBEs catering to tourists. Putri et al. [40] observed that residents in Kampung Lio, Depok, adapt their homes for multiple businesses. Lastly, Putra et al. [41] investigated housing activities in Bandung, emphasizing the need for spacious and flexible housing designs to accommodate various domestic and social activities. Together, these studies underline the necessity of adaptable housing designs to support the dual function of homes as residential and commercial spaces.

 

With this revision, we newly added the following articles in the references:

9. Kubota, T. et al. The effects of night ventilation technique on indoor thermal environment for residential buildings in hot-humid climate of Malaysia. Energy and Buildings, 2009, 41 (8), pp. 829–839. DOI: 10.1016/j.enbuild.2009.03.008
10. Toe, D., & Kubota, T. Field Measurement on thermal comfort in traditional Malay houses. Aij Journal of Technology and Design, 19, 219-224, 2013. https://doi.org/10.3130/AIJT.19.219
11. Djamila, H. et al. Field study of thermal comfort in residential buildings in the equatorial hot-humid climate of Malaysia. Building and Environment, 2013, 62, pp. 133–142. DOI: 10.1016/j.buildenv.2013.01.017
12. Irakoze, A. et al. Holistic Approach towards a Sustainable Urban Renewal: Thermal Comfort Perspective of Urban Housing in Kigali, Rwanda. Buildings, 2023, 13 (1), p. 146. DOI: 10.3390/buildings13010146
13. Naicker, N.; Teare, J.; Balakrishna, Y.; Wright, C.Y.; Mathee, A. Indoor Temperatures in Low Cost Housing in Johannesburg, South Africa. Int. J. Environ. Res. Public Health 2017, 14, 1410. https://doi.org/10.3390/ijerph1411141014
14. WRI Indonesia. Seizing Indonesia Urban Opportunity: Compact, Connected, Clean and Resilient Cities as Drivers of Sustainable Development. 2021
15. UN Habitat. World Cities Report 2022. https://unhabitat.org/sites/default/files/2022/06/wcr_2022
16. BPS - Statistic of Surakarta Municipality. Surakarta Municipality in Figure 2024. Vol. 48
17. Obemeyer, C. Sustainable City Management – Informal Settlements in Surakarta, Indonesia. Springer, 2017. Available from: https://link.springer.com/book/10.1007/978-3-319-49418-0
18. Murtyas, S. et al. On-site measurement and evaluations of indoor thermal environment in low-cost dwellings of urban Kampung district. Building and Environment, 2020, 184, p. 107239. DOI: 10.1016/j.buildenv.2020.107239
19. Murtyas, S. et al. Assessment of Mould Risk in Low-Cost Residential Buildings in Urban Slum Districts of Surakarta City, Indonesia. Buildings, 2023, 13 (5), p. 1333. DOI: 10.3390/buildings13051333
20. Hildebrandt, S. et al. Indoor Air Quality and Health in Newly Constructed Apartments in Developing Countries: A Case Study of Surabaya, Indonesia. Atmosphere, 2019, 10 (4), p. 182. DOI: 10.3390/atmos10040182
21. Sani, H. et al. Impacts of Air Pollution and Dampness on Occupant Respiratory Health in Unplanned Houses: A Case Study of Bandung, Indonesia. Atmosphere, 2022, 13 (8), p. 1272. DOI: 10.3390/atmos13081272
22. Prihardanu, E.G. et al. Indoor air quality in urban residential: Current status, regulation and future research for Indonesia. International Journal of Public Health Science (IJPHS), 2021, 10 (4), p. 824. DOI: 10.11591/ijphs.v10i4.20885
23. Chen, M.A. Informal Economy Monitoring Study Sector Report: Home-based Workers. [no date].
24. Chen, M.A. et al. Home-based workers and cities. Environment and Urbanization, 2016, 28 (2), pp. 343–358. DOI: 10.1177/0956247816649865
25. Hassler, M. Home-working in Rural Bali: The Organization of Production and Labor Relations*. The Professional Geographer, 2005, 57 (4), pp. 530–538. DOI: 10.1111/j.1467-9272.2005.00497.x
26. Adhikary, D.M. et al. Health Expenditure of Home Based Worker & Access to Usable Water & Sanitation: A Case Study of Bidi workers in Purulia of West Bengal. 2016, 1.
27. M, M. Hazards in cottage industries in developing countries. 1996, 30 (2). DOI: 10.1002/(SICI)1097-0274(199608)30:2<125::AID-AJIM2>3.0.CO;2-#
28. Tipple, G. Employment and work conditions in home-based enterprises in four developing countries: do they constitute ‘decent work’? Sage, 2006, 20 (1), pp. 167–179. DOI: https://doi.org/10.1177/0950017006061280
29. Tipple, G. The Place of Home-based Enterprises in the Informal Sector: Evidence from Cochabamba, New Delhi, Surabaya and Pretoria. Sage, 2005, 42 (4). DOI: https://doi.org/10.1080/00420980500060178
30. Gamal, A. et al. Housing preference shifting during COVID-19 pandemic in Indonesia. Journal of Urban Management, 2023, 12 (3), pp. 268–283. DOI: 10.1016/j.jum.2023.05.002
31. Kusumaningdyah, N.H. Features and Issues of Urban Industrial Batik Cluster Development in Surakarta and Yogyakarta, Indonesia. Transaction of AIJ, 2013, 78 (686), pp. 837–846. DOI: DOI:10.3130/aija.78.837
32. Lawanson, T. et al. The Home as Workplace: Investigating Home Based Enterprises in Low Income Settlements of the Lagos Metropolis. Ethiopian Journal of Environmental Studies and Management, 2012, 5 (4), pp. 397–407. DOI: 10.4314/ejesm.v5i4.9
33. Ezeadichie, N. Home-Based Enterprises in Urban Spaces: An Obligation for Strategic Planning? Berkeley Planning Journal, 2012, 25 (1). DOI: 10.5070/BP325112010
34. Wagemann, E. et al. Housing and home-based work: Considerations for development and humanitarian contexts. Cities, 2024, 147, p. 104833. DOI: 10.1016/j.cities.2024.104833
35. Kusumaningdyah, N.H. et al. The Impact of Home-based Enterprises to Kampung Settlement Case Study of Serengan District, Surakarta. 2019
36. Sihombing, A. et al. The Role of Millennial Urban Lifestyles in the Transformation of Kampung Kota in Indonesia. Environment and Urbanization ASIA, 2020, 11 (1), pp. 155–169. DOI: 10.1177/0975425320906288
37. Kusumaningdyah, N.H.; Sakai, T.; Deguchi, A.; & Divigalpitiya, P.The Productive Space of Kampung Kota Settlement : A Case Study Semanggi District, Surakarta - Indonesia. 2018. DOI: 10.15017/1961289
38. Prakoso, S. et al. Spatial Characteristics of Home as Workplace: Investigation of Home-Based Enterprise in Several Housing Typologies in Indonesia. Built Environment, 2023, 49 (3), pp. 397–422. DOI: 10.2148/benv.49.3.397
39. Suparwoko et al. Home-based Enterprises in the International Kampong of Sosrowijayan: Housing Typology and Hybrid Cultural Approach to Tourism Development. In: Proceedings of the EduARCHsia & Senvar 2019 International Conference (EduARCHsia 2019). Yogyakarta, Indonesia: Atlantis Press, 2020. DOI: 10.2991/aer.k.200214.020
40. Putri, F.E. et al. Double layered home-based enterprises: case study in Kampung Lio, Depok. IOP Conference Series: Materials Science and Engineering, 2019, 620 (1), p. 012002. DOI: 10.1088/1757-899X/620/1/012002
41. Gierlang, B.P. et al. Housing Activities in Contemporary Indonesian Dwellings. Journal of the Korean Housing Association, 2016, 27 (6), pp. 65–75. DOI: 10.6107/JKHA.2016.27.6.065

 

 

 

(3) Please offer a comprehensive description of the research methodology, specifying the criteria for sample selection, detailed steps for data collection, and the methods of analysis. This will enhance the reproducibility of the study and the credibility of its methodology.

 

Thank you for your feedback. To respond your suggestion, we modified the second section as below to provide the strategy of the selection of the surveyed districts and dwellings.

 

Section 2.2, from line 202: strategy to decide target districts and HBE dwellings

For our field survey, we selected twelve HBE dwellings located at four different districts, as shown in Figure 1. Figures 3 and 4 illustrate the map and appearance of these districts. The first district is Rukun Warga (RW 13) within Kampung Sangkrah, located in Sangkrah, District of Pasar Kliwon, Surakarta (hereafter, District S). This area was selected as a typical urban informal residential district from 29 existing urban slum areas in Surakarta City. District S is notable for its high poverty rate of 30 % [1480] and high population density, recorded at 16,101 people per square kilometer according to the 2024 BPS‐Statistics of Surakarta [43]. Figures 3(a) and 4(a) display typical urban slum characteristics, with a dense aggregation of variously sized buildings and a notably irregular layout in relation to the surrounding streets.

In addition, we adopted three districts from four newly built areas under the urban slum upgrading projects initiative by Surakarta City, known as the Kota Tanpa Kumuh (KOTAKU) programme. These districts are Kampung Metal Mojo (hereafter, District M), Kampung HP 00001 (hereafter, District H), and Kampung Tipes (hereafter, District T), which are located within 5 km of District S. The selection criteria for these three districts were the contrasting geometries of their architectural designs. As shown in Figures 3 and 4, Districts M, H and T represent newly built residential areas aimed at upgrading substandard urban slum settlements. In District M, long row‐house‐style buildings were constructed along the street, housing a total of 56 dwelling units in 2021. Conversely, District H consists of townhouses, with a total of 523 dwelling units built since 2021. Meanwhile, in District T, a total of 63 households resides in townhouses, consisting of 4 units constructed in 2022.

In Districts M, H, and T, the columns and beams made of concrete modules, roofs, and concrete block walls were constructed at the municipalityʹs expense. In contrast, the residents were responsible for finishing the interiors and exteriors, as well as installing exteriors, as well as installing window sashes and ventilation openings. Consequently, the size and position of windows and ventilation openings vary from one dwelling to another.

 

Section 2.2, from line 271: method to recruit households for cooperating to our survey

The study involves not only conducting interviews with residents but also entering the residences—a highly private space—for observations and taking photographs. To facilitate this, we recruited twelve households willing to cooperate with the study, having established a trusting relationship with the residents and communities through repeated visits over the past five years.

 

Section 2.2, from line 276: issue of limited sample number

Considering that the number of substandard dwellings in Surakarta City was approximately 12,000 as of 2022 [44] (with the number of substandard HBE dwellings not specifically reported), our survey sample of twelve households is extremely small and cannot be considered statistically representative. Nevertheless, this exploratory study is a first attempt to understand the actual indoor thermal environment of HBE housing in Indonesia and to elucidate the design of HBE housing and occupant behaviors as dominant factors affecting the indoor thermal environment. Therefore, we believe this in‐depth survey of twelve HBE dwellings has significant academic value despite its limited sample size.

 

Section 2.3, from line 307: method of observation of building design and space use

In addition, the building design, including the geometry and material of each component, layout of the furniture, and usage of space in each dwelling were meticulously documented through photographs, sketches, and drawings. The major variables used for analysis are shown in Table 2. Past field measurements in a non-air conditioned terrace house in Malaysia, which share similar climate conditions with our current research site, revealed the significant impact of natural ventilation on space cooling [47]. Therefore, the presence and size of openings exposed to the outside air in each room were included in our analysis.

 

Table 2. Observed building-related variables

Categories	Variables	Secondary variables
For each dwelling	·   Total floor area ·   Materials of building envelop and roof ·   Relation to adjacent buildings (detached or attached) ·   Number of rooms, occupants, and home workers	·   Total floor area per occupants ·   Ratio of HBE space to total floor area ·   Ratio of multi-use space in HBE area
For each room	·   Floor area ·   Floor area used for HBE activities ·   Floor area of multi-use space, including HBE activities ·   Number of openings	·   Ratio of openings to floor area
For each door and windows	·   Width and height ·   Whether it is exposed to the outside or not ·   Whether it is open most of the day

 

 

(4) The discussion section should further explore the socio-economic factors behind residents' behaviors that affect the indoor thermal environment. This will contribute to a more comprehensive understanding of the study's results and provide deeper in sights for the formulation of relevant policies and measures.

 

We appreciate your valuable suggestion.

To provide the socio-economic information of the surveyed dwellings, we modified Table 1, adding the classification of household income as below.

 

         Table 1. Outline of surveyed HBE dwellings

District	Dwelling	HBE type	Number of occupants (HBE workers)	Land area (m2)	Floor area (m2)	Number of floors	Number of rooms*	Household income
S	S1	Gallery of artisan puppet and traditional musical instruments	7 (2)	457.7	517.6	2	12	Middle to high
	S2	Clothing & Grocery	4 (2)	54.6	60.0	1 + L**	5	Low
	S3	Food shop (cooking and selling chicken noodle)	5 (2)	72.5	109.6	2	8	Low
	S4	Tailor	4 (1)	44.7	93.5	2	7	Low
	S5	Laundry	6 (2)	124.2	97.2	1	7	Low
	S6	Grocery store	3 (2)	306.7	116.1	1	6	Low
M	M1	Tailor	5 (2)	34.7	34.7	1	3	Low
	M2	Ironing Service	3 (1)	32.6	32.6	1	3	Low
H	H1	Tailor	4 (1)	48.0	52.2	1 + L**	5	Low
	H2	Food stall	1 (1)	36.0	36.0	1	3	Low
T	T1	Shuttlecock manufacture	4 (1)	14.1	35.3	2	3	Low
	T2	Food stall	6 (2)	14.1	34.2	2 + L**	4	Low

           *: Water-related spaces are excluded.  **: Loft space attached by residents.

 

Unfortunately, we cannot statistically discuss the socio-economic effects on the occupants’ behaviors and housing design due to the limited sample number. Nevertheless, we have included the following descriptions to provide more detailed understanding of the relevant factors.

 

Section 3.4, line 475: effect of the urban-slum upgrading projects

Table 4 presents the building design features critically affecting natural ventilation effectiveness and the indoor thermal environment. Notably, 10 of the 12 dwellings surveyed are semi‐detached or terraced, sharing two or three external walls with neighboring buildings. This configuration limits the availability of windows and other openings. This setup is especially common in the six dwellings within Districts M, H, and T, which were designed as part of a slum upgrading initiative and are constrained by limited land availability. In particular, dwelling M2 is enclosed by three other dwellings, with only the entrance side wall exposed to the outside air. As a basic design policy for housing complexes in urban slum upgrading projects, each unit should be designed to face at least two sides to the outside air, regardless of land constraints. In contrast, dwellings S1 and S6 stand as detached houses, fully independent and with ample surrounding space— a rarity within the densely constructed District S.

 

Section 3.4, line 496: weak air circulation due to small store space

Dwelling S6, benefiting from a larger site with vacant surrounding land, nonetheless exhibits limited cross‐ventilation potential due to minimal windows or openings on the far end and sides of external walls, as seen from the entrance (Figure 6(a)). As a result, the living room, kitchen, and bedroom have no windows. Additionally, as shown in Figure 8, even in the HBE space with openings in two locations, a large number of products are stacked from floor to ceiling in the extremely narrow store interior, causing poor air circulation. Such a design flaw, despite ample space with adequate privacy, might be attributed to incremental, low‐cost renovations by residents without professional architectural input. This issue, alongside other floor plans detailed in Appendix Figure A1, underscores that challenges in achieving effective cross‐ventilation stem not only from site constraints but also from a lack of awareness among residents and local builders about the critical need for strategic opening design.

 

Figure 8. A narrow store space occupied by many products (Dwelling S6)

Section 3.5, line 542: Lack of awareness or understanding of ventilation in opening design

Lastly, despite the daily habit of introducing outside air by opening windows and doors, and an apparent understanding of the benefits of natural ventilation among residents, cross ventilation is notably absent in the building designs, as shown in Table 4. The majority of the surveyed dwellings, whether in kampung areas or urban slum upgrading projects, are constructed incrementally. Residents modify the interiors, exteriors, or openings of their homes based on their preferences, needs, and financial capabilities. However, securing openings or installing exhaust fans for ventilation does not appear to be a commonly considered option.

To improve the current situation, it is important to provide not only financial support but also knowledge support. This includes sharing specific methods to enhance natural ventilation, such as determining the size and position of openings, designing layouts, and other techniques with community members and small local construction businesses involved in the building process.

 

 

(5) The conclusion section should clearly reflect the main findings of the paper and point out the limitations of the study. Additionally, suggest directions for future research to provide guidance for subsequent investigators.

 

Thank you for the suggestion. According to this comment, we modified the descriptions about main findings as below.

 

Section 4, line 568: main findings

Key findings from this study include:

• Thermal measurements inside six dwellings revealed temperatures exceeding 30°C for 50‐60% of working hours. This indicates a breach of acceptable thermal comfort standards and highlights the necessity for improvement in working conditions.
• Due to limited available land, the floor area per occupant varied between 8.6 to 13 m² in most of the dwellings studied. Additionally, most dwellings shared two or three exterior walls with adjacent buildings. These densely populated conditions resulted in limited openings and significantly hampered cross‐ventilation. Nine surveyed homes even had bedrooms without windows.
• Certain types of HBE activities, notably ironing and cooking, generated significant heat and water vapor indoors over extended periods. Despite this, none of the homes featured mechanical ventilation systems; reliance was solely on natural ventilation through open windows and doors.
• To maximize comfort under severe constraints, residents typically opened windows and doors to introduce outside air and conducted HBE activities in larger spaces with multiple openings. Despite these routine habits, there is a lack of effective building design to ensure cross‐ventilation. In the surveyed dwellings that were incrementally modified, creating openings or installing exhaust fans for ventilation does not seem to be a commonly considered option.

Overall, this research has illuminated the pressing issue of hot and inadequate working conditions for HBE workers living in low‐cost dwellings in Surakarta City, Indonesia. The findings underscore the urgent need for better architectural strategies and facilities that are applicable for both urban‐slum upgrading projects and the incremental construction of existing slum housing. Although there are challenges posed by economic constraints, the following actions are specifically recommended:

• In the context of urban‐slum upgrading projects, it is imperative to ensure cross‐ventilation. This can be achieved by designing layouts where at least two sides of each building do not share walls with adjacent structures, thereby incorporating openings that face the external environment.
• It is essential to enhance the understanding of both residents and local construction workers regarding the importance of installing windows in appropriate positions and sizes. This knowledge can then be applied in the incremental renovation practices within the urban informal settlements and upgraded ones. To achieve this, advice and enlightenment from experts such as scholars and architects for the communities would be effective.

 

Section 4, line 607: Limitation of this study and future direction of expected studies

Our study offers valuable insights. However, the relatively small sample size could limit the robustness of our conclusions. Additionally, the study is geographically confined to Surakarta City and may not be directly applicable to other cities in Indonesia. In light of these findings, future research should explore the following points:

• Ventilation-Related Design Parameters: Incrementally constructed low-cost dwellings are highly diverse, with numerous design variables affecting the indoor thermal environment. Future studies should focus on cross-ventilation factors, such as windowless rooms. Conducting field surveys on a larger number of samples will clarify the background and influencing factors that lead to flawed designs.
• Design Guidelines Development: For urban-slum upgrading projects, it is crucial to develop design guidelines for low-rise housing. Recent studies have optimized building passive design for indoor thermal comfort and energy savings using surrogate-assisted models under various contexts [51]. Research using these methods will be advantageous in exploring appropriate designs that consider ventilation, lighting, and functionality within economic and land constraints.
• Surveying Strategies: In urban-slum upgrading projects across various Indonesian cities, particularly for constructing low-rise housing, it is important to survey the strategies employed by relevant sectors at all stages of planning, design, construction, and renovations by residents. These surveys will help identify ways to convey academic knowledge to stakeholders, ensuring better housing designs.

 

 

(6) As a scientific paper, the layout and display of figures and tables require further improvement.

 

Thank you very much for your valuable input. To respond this comment, we fully improved the layout and display figure. Some improvement are as below.

 

We modified Figure 1 Location of Surakarta City and surveyed districts with new clear legenda on the map. Thick line describe the street and boundaries area’s research

Figure 1 Location of Surakarta City and surveyed districts

 

We modified Figure 3 Site plan of target districts with new legenda of dwellings of HBE as case study, clear color for Blok plan area’s out of case study.

 

 

 

 

 

Figure 3 Site plan of target districts

 

We appreciate your correction. We newly added the complete Figure 4 as the following above

 

 

Figure 4 Appearance of survey district

 

We newly added the detail figures 5 as shown below, which visualize clearly description as highlighted by red color.

 

Figure 5. (a) Averaged daily fluctuation of operative temperature and (b) PMV at six dwellings of district S during HBE working hours

 

Figure 6.  (a) Cumulative probability density distributions of operative temperatures and (b) PPD at six dwellings of District S during HBE working hours

 

We newly added the detail figures 7 as shown below, which visualize clearly description as highlighted by each houses

 

 

 

 

(a) Dwelling S3 (Chicken noodle stall)

(b) Dwelling S5 (Laundry service)

(c) Dwelling M2 (Ironing Service)

(d) Dwelling H2 (Food stall)

(e) Dwelling T2 (Food stall)

 

Figure 7. Potential emission sources due to HBE activities

 

 

 

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

This study investigates indoor thermal conditions in home-based enterprises (HBEs) within the informal urban settlements of Surakarta City, Indonesia, focusing on the struggle for thermal comfort under constrained conditions. Comments can be found below,

A more extensive review would help contextualize the findings and highlight gaps in current knowledge.

The study focuses on a relatively small number of dwellings (12), while given the diversity of urban low-cost housing, whether the results can be applied in other conditions?

The field measurements were conducted over a limited period (41 days), why do you conduct the measurements for longer time?

Other factors that may influence indoor thermal comfort, such as variations in household income, access to cooling technologies, and differences in building materials and designs were not considered, please give the reason.

The figures and tables included in the paper are helpful but could be more detailed. Enhancing the visual quality and adding more comprehensive legends would aid in better understanding the data presented.

Comments on the Quality of English Language

 Moderate editing of English language required

Author Response

Response to Reviewer: 4

 

I, along with my co-authors, would like to express our appreciation to your comments on our paper titled “Thermal Comfort Challenges in Home-Based Enterprises: A Field Study from Surakarta’s Urban Low-Cost Housings in a Tropical Climate”. The comments have helped us improve the manuscript. According to your comments and suggestions, we have revised the manuscript. We highlighted the newly added or modified parts by red color.

 

(1) A more extensive review would help contextualize the findings and highlight gaps in current knowledge.

 

We appreciate your valuable suggestion. We thoroughly surveyed the past studies, and reorganized the majority of the introduction section as below.

 

Section 1, line 45: research on indoor thermal condition of housing at hot climate zone

With such a background, the indoor thermal conditions of naturally-ventilated residential buildings in South-East Asia and other developing regions with hot climates have been extensively investigated, focusing on occupants' thermal comfort, health, and living quality. For example, Kubota et al. [9] conducted a field experiment in typical terrace houses to examine the effectiveness of ventilation as a passive cooling method. They found that night ventilation improves thermal comfort but also emphasized the need for indoor humidity control during the daytime. Toe and Kubota [10] measured indoor thermal conditions in traditional Malay houses in Malaysia under natural ventilation and revealed that indoor air temperatures were generally higher than outdoor temperatures, underscoring the importance of passive cooling techniques. Djamila and Kumaresan [11] conducted a field survey of indoor thermal comfort among 890 occupants and assessed physical indoor thermal variables in non-air-conditioned residences in Kota Kinabalu, Malaysia. They suggested that high indoor temperatures necessitate passive cooling strategies in building designs. Irakoze and Kim [12] evaluated the indoor thermal conditions of three main urban housing types—informal settlements, planned low-income housing, and modern urban housing—in Kigali, Rwanda, located in a tropical highland climate zone, using building energy simulations. Naicker and Mathee [13] reported high heat risk based on indoor temperature measurements in 100 low-cost houses in South Africa.

 

Section 1, from line 79: research on indoor thermal condition of Indonesian housing

For instance, a study conducted by Murtyas et al. [18] involved field measurements of the indoor thermal conditions in 17 urban slum dwellings in Surakarta, Indonesia. Their findings revealed that the majority of these houses failed to meet the thermal comfort criteria established by ASHRAE55-2017 for most hours, resulting in a high risk of heatstroke. Based on the measured data from this study, Murtyas et al. [19] also reported a high mould risk in low-cost housing due to high humidity and poor ventilation. Hildebrandt et al. [20] investigated the indoor air quality and health conditions of occupants in newly constructed high-rise apartments and traditional kampung houses in Surabaya. They found that while high-rise apartments had higher levels of formaldehyde and total volatile organic compounds, mould issues were more severe in kampung housing due to higher humidity and poor ventilation. Similarly, Hanief et al. [21] reported field measurements of indoor air quality and humidity in informal settlements in Bandung, Indonesia, highlighted the elevated mold risk associated with low construction quality and the hot, humid climate. Furthermore, Prihardanu et al. [22] reviewed recent field studies on indoor air quality of housing and relevant national regulations and standards, suggesting inadequate ventilation in housing and gaps in the implementation of mandatory regulations.

 

 

 

Section 1, line 95: research on home-based workers in developing countries

Meanwhile, several studies have indicated that a significant proportion of residents in informal settlements in developing countries are engaged in home-based work, one of the three typical urban informal occupational groups alongside street vendors and waste pickers [23,24]. Home-based workers, particularly those who are self-employed or sub-contracted, often find themselves more vulnerable to the influence of the macroeconomic environment [25]. Furthermore, they are exposed to substandard indoor working conditions due to low-quality housing [26] and hazardous pollutants from the indoor manufacturing activities [27]. In 2006, Tipple [28] reported the results of surveys of home-based enterprise (HBE) households in Cochabamba, Bolivia; New Delhi, India; Surabaya, Indonesia; and Pretoria, South Africa, highlighting their poor working conditions and various health risks. Almost 20 years after the publication of this paper, working and living conditions in HBE continue to be a problem in many developing countries.

 

 

Section 1, from line 115: research on design and planning of HBE housing in Indonesia

The integration of HBEs in small low-cost housing in Indonesia presents unique features of adaptive space usage, as explored by several key studies. Sihombing [36,37] reported that the architecture of kampung houses often evolves to incorporate in-house businesses, such as “warung” (small stalls), laundry services, food shops, and other commercial ventures to meet local demands. Spaces within HBE dwellings are notably flexible; serving multiple purposes—ranging from a workspace to a living room—depending on the time of day. Prakoso and Dewi [38] highlighted the use of flexible spaces to reduce conflicts between living and working areas. Suparwoko and Raharjo [39] examined the blend of local and western influences in Yogyakarta HBEs catering to tourists. Putri et al. [40] observed that residents in Kampung Lio, Depok, adapt their homes for multiple businesses. Lastly, Putra et al. [41] investigated housing activities in Bandung, emphasizing the need for spacious and flexible housing designs to accommodate various domestic and social activities. Together, these studies underline the necessity of adaptable housing designs to support the dual function of homes as residential and commercial spaces.

 

With this revision, we newly added the following articles in the references:

9. Kubota, T. et al. The effects of night ventilation technique on indoor thermal environment for residential buildings in hot-humid climate of Malaysia. Energy and Buildings, 2009, 41 (8), pp. 829–839. DOI: 10.1016/j.enbuild.2009.03.008
10. Toe, D., & Kubota, T. Field Measurement on thermal comfort in traditional Malay houses. Aij Journal of Technology and Design, 19, 219-224, 2013. https://doi.org/10.3130/AIJT.19.219
11. Djamila, H. et al. Field study of thermal comfort in residential buildings in the equatorial hot-humid climate of Malaysia. Building and Environment, 2013, 62, pp. 133–142. DOI: 10.1016/j.buildenv.2013.01.017
12. Irakoze, A. et al. Holistic Approach towards a Sustainable Urban Renewal: Thermal Comfort Perspective of Urban Housing in Kigali, Rwanda. Buildings, 2023, 13 (1), p. 146. DOI: 10.3390/buildings13010146
13. Naicker, N.; Teare, J.; Balakrishna, Y.; Wright, C.Y.; Mathee, A. Indoor Temperatures in Low Cost Housing in Johannesburg, South Africa. Int. J. Environ. Res. Public Health 2017, 14, 1410. https://doi.org/10.3390/ijerph1411141014
14. WRI Indonesia. Seizing Indonesia Urban Opportunity: Compact, Connected, Clean and Resilient Cities as Drivers of Sustainable Development. 2021
15. UN Habitat. World Cities Report 2022. https://unhabitat.org/sites/default/files/2022/06/wcr_2022
16. BPS - Statistic of Surakarta Municipality. Surakarta Municipality in Figure 2024. Vol. 48
17. Obemeyer, C. Sustainable City Management – Informal Settlements in Surakarta, Indonesia. Springer, 2017. Available from: https://link.springer.com/book/10.1007/978-3-319-49418-0
18. Murtyas, S. et al. On-site measurement and evaluations of indoor thermal environment in low-cost dwellings of urban Kampung district. Building and Environment, 2020, 184, p. 107239. DOI: 10.1016/j.buildenv.2020.107239
19. Murtyas, S. et al. Assessment of Mould Risk in Low-Cost Residential Buildings in Urban Slum Districts of Surakarta City, Indonesia. Buildings, 2023, 13 (5), p. 1333. DOI: 10.3390/buildings13051333
20. Hildebrandt, S. et al. Indoor Air Quality and Health in Newly Constructed Apartments in Developing Countries: A Case Study of Surabaya, Indonesia. Atmosphere, 2019, 10 (4), p. 182. DOI: 10.3390/atmos10040182
21. Sani, H. et al. Impacts of Air Pollution and Dampness on Occupant Respiratory Health in Unplanned Houses: A Case Study of Bandung, Indonesia. Atmosphere, 2022, 13 (8), p. 1272. DOI: 10.3390/atmos13081272
22. Prihardanu, E.G. et al. Indoor air quality in urban residential: Current status, regulation and future research for Indonesia. International Journal of Public Health Science (IJPHS), 2021, 10 (4), p. 824. DOI: 10.11591/ijphs.v10i4.20885
23. Chen, M.A. Informal Economy Monitoring Study Sector Report: Home-based Workers. [no date].
24. Chen, M.A. et al. Home-based workers and cities. Environment and Urbanization, 2016, 28 (2), pp. 343–358. DOI: 10.1177/0956247816649865
25. Hassler, M. Home-working in Rural Bali: The Organization of Production and Labor Relations*. The Professional Geographer, 2005, 57 (4), pp. 530–538. DOI: 10.1111/j.1467-9272.2005.00497.x
26. Adhikary, D.M. et al. Health Expenditure of Home Based Worker & Access to Usable Water & Sanitation: A Case Study of Bidi workers in Purulia of West Bengal. 2016, 1.
27. M, M. Hazards in cottage industries in developing countries. 1996, 30 (2). DOI: 10.1002/(SICI)1097-0274(199608)30:2<125::AID-AJIM2>3.0.CO;2-#
28. Tipple, G. Employment and work conditions in home-based enterprises in four developing countries: do they constitute ‘decent work’? Sage, 2006, 20 (1), pp. 167–179. DOI: https://doi.org/10.1177/0950017006061280
29. Tipple, G. The Place of Home-based Enterprises in the Informal Sector: Evidence from Cochabamba, New Delhi, Surabaya and Pretoria. Sage, 2005, 42 (4). DOI: https://doi.org/10.1080/00420980500060178
30. Gamal, A. et al. Housing preference shifting during COVID-19 pandemic in Indonesia. Journal of Urban Management, 2023, 12 (3), pp. 268–283. DOI: 10.1016/j.jum.2023.05.002
31. Kusumaningdyah, N.H. Features and Issues of Urban Industrial Batik Cluster Development in Surakarta and Yogyakarta, Indonesia. Transaction of AIJ, 2013, 78 (686), pp. 837–846. DOI: DOI:10.3130/aija.78.837
32. Lawanson, T. et al. The Home as Workplace: Investigating Home Based Enterprises in Low Income Settlements of the Lagos Metropolis. Ethiopian Journal of Environmental Studies and Management, 2012, 5 (4), pp. 397–407. DOI: 10.4314/ejesm.v5i4.9
33. Ezeadichie, N. Home-Based Enterprises in Urban Spaces: An Obligation for Strategic Planning? Berkeley Planning Journal, 2012, 25 (1). DOI: 10.5070/BP325112010
34. Wagemann, E. et al. Housing and home-based work: Considerations for development and humanitarian contexts. Cities, 2024, 147, p. 104833. DOI: 10.1016/j.cities.2024.104833
35. Kusumaningdyah, N.H. et al. The Impact of Home-based Enterprises to Kampung Settlement Case Study of Serengan District, Surakarta. 2019
36. Sihombing, A. et al. The Role of Millennial Urban Lifestyles in the Transformation of Kampung Kota in Indonesia. Environment and Urbanization ASIA, 2020, 11 (1), pp. 155–169. DOI: 10.1177/0975425320906288
37. Kusumaningdyah, N.H.; Sakai, T.; Deguchi, A.; & Divigalpitiya, P.The Productive Space of Kampung Kota Settlement : A Case Study Semanggi District, Surakarta - Indonesia. 2018. DOI: 10.15017/1961289
38. Prakoso, S. et al. Spatial Characteristics of Home as Workplace: Investigation of Home-Based Enterprise in Several Housing Typologies in Indonesia. Built Environment, 2023, 49 (3), pp. 397–422. DOI: 10.2148/benv.49.3.397
39. Suparwoko et al. Home-based Enterprises in the International Kampong of Sosrowijayan: Housing Typology and Hybrid Cultural Approach to Tourism Development. In: Proceedings of the EduARCHsia & Senvar 2019 International Conference (EduARCHsia 2019). Yogyakarta, Indonesia: Atlantis Press, 2020. DOI: 10.2991/aer.k.200214.020
40. Putri, F.E. et al. Double layered home-based enterprises: case study in Kampung Lio, Depok. IOP Conference Series: Materials Science and Engineering, 2019, 620 (1), p. 012002. DOI: 10.1088/1757-899X/620/1/012002
41. Gierlang, B.P. et al. Housing Activities in Contemporary Indonesian Dwellings. Journal of the Korean Housing Association, 2016, 27 (6), pp. 65–75. DOI: 10.6107/JKHA.2016.27.6.065

 

(2) The study focuses on a relatively small number of dwellings (12), while given the diversity of urban low-cost housing, whether the results can be applied in other conditions?

 

As you suggested, we fully understand the limitation of the small sample number in our study. At the same time, we would like to acknowledge the academic contribution of this study as the exploratory study on the indoor thermal conditions of HBE dwellings in Indonesia. To clarify our stand point, we added the following description.

 

Section 2.2, from line 276: issue of limited sample number

Considering that the number of substandard dwellings in Surakarta City was approximately 12,000 as of 2022 [45] (with the number of substandard HBE dwellings not specifically reported), our survey sample of twelve households is extremely small and cannot be considered statistically representative. Nevertheless, this exploratory study is a first attempt to understand the actual indoor thermal environment of HBE housing in Indonesia and to elucidate the design of HBE housing and occupant behaviors as dominant factors affecting the indoor thermal environment. Therefore, we believe this in-depth survey of twelve HBE dwellings has significant academic value despite its limited sample size.

In addition, we added the description of the limitation of this study caused by the small sample size and clarified the future research direction in the last section as below.

 

Section 4, line 607: Limitation of this study and future direction of expected studies

Our study offers valuable insights. However, the relatively small sample size could limit the robustness of our conclusions. Additionally, the study is geographically confined to Surakarta City and may not be directly applicable to other cities in Indonesia. In light of these findings, future research should explore the following points:

• Ventilation-Related Design Parameters: Incrementally constructed low-cost dwellings are highly diverse, with numerous design variables affecting the indoor thermal environment. Future studies should focus on cross-ventilation factors, such as windowless rooms. Conducting field surveys on a larger number of samples will clarify the background and influencing factors that lead to flawed designs.
• Design Guidelines Development: For urban-slum upgrading projects, it is crucial to develop design guidelines for low-rise housing. Recent studies have optimized building passive design for indoor thermal comfort and energy savings using surrogate-assisted models under various contexts [50]. Research using these methods will be advantageous in exploring appropriate designs that consider ventilation, lighting, and functionality within economic and land constraints.
• Surveying Strategies: In urban-slum upgrading projects across various Indonesian cities, particularly for constructing low-rise housing, it is important to survey the strategies employed by relevant sectors at all stages of planning, design, construction, and renovations by residents. These surveys will help identify ways to convey academic knowledge to stakeholders, ensuring better housing designs.

 

(3) The field measurements were conducted over a limited period (41 days), why do you conduct the measurements for longer time?

 

Thank you for your comment. In regions where power outages frequently occur, it is not practical to conduct continuous long-term measurements using Wi-Fi-enabled devices commonly used in developed countries. Compared to previous indoor thermal environment measurements conducted in slum housing of other countries, we believe that the 41-day measurement period used in this study is not considered short. Additionally, considering that the region is tropical and experiences minimal annual temperature fluctuations, the 41 days of data is supposed to still possess a certain degree of representativeness. Based on your comments, we have added the following description in the manuscript:

 

Section 2.4, line 324:

The measurement period coincided with the transition between the wet and dry seasons. As shown in Figure 2, due to the tropical climate near the equator, the annual variation in Surakarta City's climate is minimal compared to mid-latitude regions. Therefore, the data collected over the 41 days are considered representative for evaluating the indoor thermal environment in this hot and humid region.

 

(4) Other factors that may influence indoor thermal comfort, such as variations in household income, access to cooling technologies, and differences in building materials and designs were not considered, please give the reason.

 

Thank you for your valuable suggestion.

Unfortunately, we cannot statistically discuss the impact of income due to the limited sample number. However, to address your suggestion, we added the information of household income in section 2 as below.

 

Table 1. Outline of surveyed HBE dwellings

District	Dwelling	HBE type	Number of occupants (HBE workers)	Land area (m2)	Floor area (m2)	Number of floors	Number of rooms*	Household income
S	S1	Gallery of artisan puppet and traditional musical instruments	7 (2)	457.7	517.6	2	12	Middle to high
	S2	Clothing & Grocery	4 (2)	54.6	60.0	1 + L**	5	Low
	S3	Food shop (cooking and selling chicken noodle)	5 (2)	72.5	109.6	2	8	Low
	S4	Tailor	4 (1)	44.7	93.5	2	7	Low
	S5	Laundry	6 (2)	124.2	97.2	1	7	Low
	S6	Grocery store	3 (2)	306.7	116.1	1	6	Low
M	M1	Tailor	5 (2)	34.7	34.7	1	3	Low
	M2	Ironing Service	3 (1)	32.6	32.6	1	3	Low
H	H1	Tailor	4 (1)	48.0	52.2	1 + L**	5	Low
	H2	Food stall	1 (1)	36.0	36.0	1	3	Low
T	T1	Shuttlecock manufacture	4 (1)	14.1	35.3	2	3	Low
	T2	Food stall	6 (2)	14.1	34.2	2 + L**	4	Low

*: Water-related spaces are excluded.  **: Loft space attached by residents.

 

 

Regarding the detailed influences of building materials and designs on the indoor thermal conditions, we intentionally avoid to discuss this point in this paper due to the limited sample number. To clarify our strategy, we added the following description.

 

Section 1, line 159: target of this research

Specifically, we investigated HBE housing in four residential areas within the city of Surakarta. One area is an urban slum known as kampung, while the other three are newly constructed low-rise residential districts planned to eliminate urban slums. We conducted in-depth interviews with residents and on-site observations in twelve dwellings across these districts to grasp the characteristics of housing design and occupants’ behaviors related to the indoor thermal comfort of home workers. For six of these dwellings, we estimated the time-series thermal comfort index during working hours using existing indoor thermal environment data and evaluated the fraction of thermal discomfort hours [42][43]. In fact, these simulations have been used to explore passive cooling designs effective in improving the indoor thermal environment of tropical residences [44].

Overall, this study aims to contribute to the development of environmental improvement measures for HBE housing within Indonesia’s urban informal residential areas.

 

 

To acknowledge this limitation of this study, we added the description of the future research direction in Section 4.

 

Section 4, line 617: Expected studies considering design impact to establish design guidelines

• Design Guidelines Development: For urban-slum upgrading projects, it is crucial to develop design guidelines for low-rise housing. Recent studies have optimized building passive design for indoor thermal comfort and energy savings using surrogate-assisted models under various contexts [50]. Research using these methods will be advantageous in exploring appropriate designs that consider ventilation, lighting, and functionality within economic and land constraints.

 

(5) The figures and tables included in the paper are helpful but could be more detailed. Enhancing the visual quality and adding more comprehensive legends would aid in better understanding the data presented.

 

Thank you very much for your valuable input. To respond this comment, we fully improved the layout and display figure. Some improvement are as below.

We modified Figure 1 Location of Surakarta City and surveyed districts with new clear legenda on the map. Thick line describe the street and boundaries area’s research

Figure 1 Location of Surakarta City and surveyed districts

We modified Figure 3 Site plan of target districts with new legenda of dwellings of HBE as case study, clear color for Blok plan area’s out of case study.

We appreciate your correction. We newly added the complete Figure 4 as the following above

Figure 4 Appearance of survey district

 

We newly added the detail figures 5 as shown below, which visualize clearly description as highlighted by red color.

 

 

Figure 5. (a) Averaged daily fluctuation of operative temperature and (b) PMV at six dwellings of district S during HBE working hours

Figure 6.  (a) Cumulative probability density distributions of operative temperatures and (b) PPD at six dwellings of District S during HBE working hours

We newly added the detail figures 7 as shown below, which visualize clearly description as highlighted by each houses

 

 

 

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

All my comments have been taken into account. The article can be published.

Reviewer 3 Report

Comments and Suggestions for Authors

The paper has been well revised and is recommended for acceptance.

 

Reviewer 4 Report

Comments and Suggestions for Authors

The authors have replied the comments properly.