**Meltem Ulu <sup>1</sup> and Zeynep Durmu¸s Arsan 2,\***


Received: 31 May 2020; Accepted: 7 July 2020; Published: 13 July 2020

**Abstract:** Energy-efficient retrofitting of historic housing stock requires methodical approach, in-depth analysis and case-specific regulatory system, yet only limited efforts have been realized. In large scale rehabilitation projects, it is essential to develop a retrofit strategy on how to decide energy-efficient solutions for buildings providing the most energy saving in a short time. This paper presents a pilot study conducted at a neighborhood scale, consisting of 22 pre-, early-republican and contemporary residential buildings in a historic urban fabric in the Mediterranean climate. This study aims to develop an integrated approach to describe case-specific solutions for larger scale historic urban fabric. It covers the building performance simulation (BPS) model and numerical analysis to determine the most related design parameters affecting annual energy consumption. All the case buildings were classified into three main groups to propose appropriate retrofit solutions in different impact categories. Retrofit solutions were gathered into two retrofit packages, Package 1 and 2, and separately, three individual operational solutions were determined, considering a five-levelled assessment criteria of EN 16883:2017 Standard. Energy classes of case buildings were calculated based on National Building Energy Regulations. Changes in building classes were evaluated considering pre- and post-retrofit status of the buildings. For the integrated approach, the most related design parameters on annual energy consumption were specified through Pearson correlation analysis. The approach indicated that three buildings, representing each building group, can initially be retrofitted. For all buildings, while maximum energy saving was provided by Package 2 with 48.57%, minimum energy saving was obtained from Package 1 with 19.8%.

**Keywords:** energy-efficient retrofit; historic residential buildings; energy consumption prediction

#### **1. Introduction**

Many countries have introduced numerous policy measures and strategies on energy efficiency depending on national circumstances and political goals, together with increasing risks of climate change and global warming, rapidly depleting natural sources and rising energy demand/consumption [1]. There is an urgent need to implement energy-oriented solutions for buildings, since the building sector comprises the largest portion of energy saving potential. It is explicit that the building and construction sectors are the highest final energy-consumers, being responsible for 36% and 39% of energy- and process-related emissions at global level in 2018, respectively [2]. Particularly, residential buildings account for 22% [2] and 27.2% [3] of final energy consumption in 2018 in world and the EU-28 countries, respectively. In Turkey, the residential sector has the highest share of total energy consumption, with 24.5% in 2016 [4].

While the current attention is towards the upgrading of energy-efficiency policies and retrofit efforts on existing building stock, historic buildings are also a non-negligible contributor, since historic buildings constitute over 25% of total buildings [5] and more than 40% of residential buildings in Europe were built before the 1960s [6]. In Turkey, the percentage of historic buildings built before 1945 is 6.1% [7]. Moreover, the largest share within officially registered immovable cultural properties belongs to residential buildings with 63% in 2019 [8].

Differently from other existing buildings, historic buildings form distinctive architectural and aesthetical characteristics in many urban areas, as well as keeping intangible elements, such as associations of historic people, events and aspects of social history, within cultural heritage values. They also comprise inherently sustainable characteristics in terms of material use, construction type, spatial decisions and topographic unity [9]. Energy-efficient retrofit of historic buildings is undoubtedly vital for ensuring their proper re-use to meet modern-day requirements, keeping away from desolation and demolition, enhancing comfort conditions, i.e., thermal and visual, and maintaining distinctive characteristics and heritage values.

Building conservation and energy efficiency are both key aspects for sustainable development which covers social, economic and environmental requirements and balances them in harmony. It is possible to improve the energy efficiency of historic buildings without compromising their historic fabric and distinctive characteristics [10]. The fact remains that the energy efficiency of historic buildings requires a special concern in comparison to existing one. This issue should be addressed in an interdisciplinary approach to find a convenient balance between conservation principles and energy-efficient retrofits.

Energy-efficient retrofit of existing buildings has become a prominent policy argument at both the national and international levels, specifically over the last 20 years. The European Commission (EC) enacted a series of policies and regulations addressing new and existing buildings to make them more energy efficient and reduce CO<sup>2</sup> emissions in the EU countries through Energy Performance of Building Directives (EPBDs) [11–13] and Energy Efficiency Directive (EED) [14]. The EC initially stipulated three key targets: reducing GHG emissions by 20%, increasing energy efficiency by 20% and increasing the share of renewable energy sources in energy consumption by 20% by 2020 [15]. Beyond the 2020 strategy, The EU drew longer-term low carbon economy and energy roadmaps in 2011. The low carbon economy roadmap set out target levels to reach the 2050 goal in a cost-effective way, a 40% reduction in emissions by 2030 and a 60% reduction by 2040, as well as a 25% reduction by 2020 [16]. The energy roadmap emphasizes that improving energy efficiency is a key driver in all decarbonization scenarios [17]. Recently, the recast EPBD also stipulates strong long-term renovation strategies aiming at achieving an energy-efficient and decarbonized European building stock, with indicative milestones for 2030, 2040 and 2050 [13].

As a candidate country for the EU, Turkey is upgrading its legislative efforts to be compatible with the policies of the EU. It prefaced with the first national standard, namely, the TS 825 Thermal Insulation Requirements for Buildings, which established the rules for thermal insulation in the buildings of Turkey in 2000 [18]. The Energy Efficiency Law, established in 2007, was promulgated aiming to increase energy efficiency, minimizing energy costs and ensuring the use of energy sources for a clean environment. Then, Energy Performance Regulation on Buildings was published in 2008. It obligates the building energy certification scheme, which includes information about energy classification categories and the minimum energy requirements of existing buildings for their renovation [19].

Although the EU Directives addresses the major aspects of the renovation of existing building stock and retrofitting technical elements and systems, there is no specific statement about retrofitting historic buildings. In the first EPBD 2002/91/EC, the EU left the decision about implementing minimum energy performance requirements for historic buildings to its member states [11]. The following directives revised and rearticulated this statement [12,14]. In other respects, the recast EPBD [13] promotes researching and testing of new solutions to improve the energy performance of historic buildings and sites, while safeguarding and preserving heritage value.

In Turkey, the Energy Performance Regulation on Buildings refers to a similar statement as specified in the first EPBD 2002/91/EC. The Article 2 (ç) in the Regulation indicates that energy-efficient interventions on the buildings that are officially registered as a cultural asset should be conducted by receiving the consultancy of competent authorities in a way not to affect building fabric and appearance [19]. In its 2023 projections, Turkey points out the necessity of energy improvements of existing buildings; however, there is no specific expression covering historic buildings [20].

Recently launched by the European Committee in 2017, the Standard EN 16883 Conservation of Cultural Heritage-Guidelines Improving the Energy Performance of Historic Buildings directly focuses on the energy efficiency of historic buildings. EN 16883: 2017 covers historically, architecturally or culturally valuable buildings, regardless of whether they are officially registered or not. It presents a systematic procedure about the identification of objectives for refurbishment based on various assessment categories, such as energy saving, heritage significance, economic viability, compatibility, selecting and evaluating interventions and deciding on the most appropriate ones while respecting heritage significance of buildings [21].

Consequently, there is no legal certainty about how to improve the energy efficiency of historic buildings while preserving their function, quality or character in building regulations of the EU and Turkey. Another concern is the lack of any protection procedure covering historic buildings, even if not legally protected. This situation poses a risk when it comes to physical alterations for those buildings constituting large part of historic urban centers [22].

The review of recent literature emphasizes that the lack of a specific protocol on the energy efficiency of historical buildings at an individual building level comes to the fore, as well as this lack being even more noticeable for urban scale approach [23]. Nevertheless, research on the energy efficiency of historic urban stock affirms that a certain number of publications have accelerated after 2010 in the European Countries. The course of studies is discussed in terms of diversity of the research topics, methodologies, focus groups and level of retrofit. Research topics are grouped under five sub-topics, consisting of energy efficiency, thermal comfort, environmental impact, economic impact and heritage value. Energy-efficient retrofit solutions addressing both individual cases and building stock are categorized in the surveyed publications. While individual building level solutions are related to building systems, equipment and building envelope, such as walls, floors, roofs, windows, doors and shutters, integration renewable energy sources and district heating are included in district scale solutions. Table 1 summarizes research topics and energy-efficient retrofit solutions for both building and district scale.

Improving energy efficiency while protecting the heritage value of historic buildings is an essential purpose for all studies. Additionally, some studies aim at improving thermal comfort [24–29], achieving carbon emissions reductions and assessing energy-efficient measures via life-cycle approach [30,31] and increasing economic performance with regard to cost-effectiveness [25,26,29–31] (Table 1).

District-level retrofit solutions have multiscale approach, comprising of the building scale and district scale. Regarding the building scale, the majority of studies deals with retrofit solutions on building envelope covering insulation of walls, floors and roofs and repairing or replacing door and window systems. Interior insulation of the external walls and improving windows are the most preferable ones. It is followed by improvements of the HVAC systems and equipment, while the integration of renewable energy systems has been in the minority due to concerns on building appearance and heritage value. Moreover, using weather stripping is the cheapest way to improve energy performance among the studies whilst still being effective (Table 1). Almost all studies combine single retrofit solutions, and then use these as multiple retrofit packages. Considering the district scale, Broström et al. (2014) [26] and Sugár et al. (2020) [32] propose the installation of a district heating system as a prominent solution. Bonomo and Benardinis (2014) also concentrate on the integration of solar PV technologies not only into the building but also the urban and landscape scale in a historical settlement in Italy [33].



**Table 1.** Categorization and main characteristics of the retrofit-related publications by a systematically reviewed literature.

An energy-efficient retrofit approach at district scale differs from the individual building level. Various studies have developed a neighborhood scale approach, instead of one-by-one approach, to assess the energy-efficient retrofit potential of historic building stock. They identify buildings as representative or archetype cases which characterize a specific building group to evaluate the outcomes on these cases by extrapolating to wider scale. The reason is to speed up the decision-making process in determining retrofit solutions and provide a higher level of energy-efficient improvements [23,24,27–30,34]. Several studies also present overall methodologies on deciding and evaluating the effects of energy-efficient retrofit solutions while avoiding the potential risks for historic building stock [23,31,32,35]. Eriksson et al. (2014) presented a methodology developed for EU Historic Districts' Sustainability (EFFESUS) research project to analyze the impacts of energy-efficient measures on heritage significance in a historic district in Visby, Sweden [35]. Egusquiza et al. (2018) suggested a method that provides early-stage suitability assessment of energy conservation measures (ECM) for historic urban areas within a multi-scale approach through ICOMOS guidance on Heritage Impact Assessment [23]. ECMs are evaluated to decide their impact on heritage value and Santiago de Compostela, Spain was selected to test this method, as supported by 3D models. In the study of Sugar et al. (2020), the heritage-respecting energetic retrofit methodology was developed for the historic building stock of Budapest, Hungary, based on the EPBD [32]. Blumberga et al. (2020) presented a decarbonization strategy of urban block in the historic center of Riga, Latvia by discussing the impact of energy efficiency measures on historic heritage values [31].

When planning large-scale retrofit process, extensive data collection and energy investigations are inevitable to define building characteristics, energy behavior and energy saving potential of building stock [23,31,32,34,36,37]. Building categorization is another significant indicator to determine urban typologies and, therefore, appropriate solutions are to be applied in accordance with district scale. Multiple studies list various categorization criteria, such as type of building, purpose of use, number of floors, building geometry, construction year, building system and remarkable architectural characteristics and degree of protection, as well as heritage value. The most notable one is the heritage value [23,26,29,32,38,39].

It has been seen that building performance simulation (BPS) tools are widely used not only in earlier stages of a design process for sustainability but also in analyzing existing building performance and evaluating potential retrofit solutions to attain more energy-efficient historic buildings. They are useful for obtaining fast and actual results in a short time, especially in larger scale studies [24,27,29,39].

The above-mentioned studies make explicit that energy efficiency and heritage value protection are hot topics in discussed publications. Energy-efficient retrofit of historic buildings and urban areas is a delicate matter that needs to be considered in an interdisciplinary way. Therefore, the retrofit process of historic buildings requires a distinctive roadmap in comparison to the other existing buildings. All retrofit works on historic buildings are specific in their context. Before implementing a retrofit solution, in attempt to improve energy efficiency of historic buildings, a number of principles should be thoroughly considered: intervention should be kept at a minimum level and retrofits should be reversible, compatible and respectful to the original fabric, distinctive characteristics and heritage value of buildings.

Historic districts are well-defined areas by distinctive characteristics in urban areas, in terms of size, fabric, form, construction, material used and density, as well as heritage value, integrity, memory and perception in modern urban environment. It is necessary to turn historic urban areas into an energy-efficient model for sustainable development in communities by balancing between the conservation of historic buildings and sustainability requirements to ensure their continuity for future generations while protecting their heritage value. The fact remains that, in large scale rehabilitation projects, the requirement of developing a retrofit strategy is crucial regarding the question of how to decide solutions for buildings which provide the most energy saving in a short time. Since large scale retrofit studies require extensive data collection to define building characteristics, field survey takes a long time, and the economic impact of this is high.

In historic urban fabrics of Turkey, street and/or façade rehabilitation projects are generally conducted at a neighborhood scale. They are limited to various efforts such as improving the physical appearances of buildings and façade components, painting of buildings' façades and fixing street furniture and decoration elements by protecting fabric and the distinctive characteristics of the buildings and streets. The key innovation of this study is to expand this approach from the energy-efficient point of view. The main aim of the study is to develop an integrated approach to identify case-specific energy-efficient solutions toward retrofit strategies for larger scale historic urban fabric.

The present study expands upon the current literature by bringing a distinctive decision support methodology about how to decide energy-efficient retrofit solutions at a neighborhood scale, consisting of both historic and contemporary residential buildings, in a short time and with a limited budget. It conveys an integrated roadmap to speed up the decision-making process in determining more precise and context-specific retrofit solutions for larger scale historic urban fabric. Moreover, this study will be the first in Turkey which considers historic building retrofit from an energy-efficiency point of view at the urban scale.

#### **2. Case Study**

The study has been carried out in the neighborhood located in Basmane District, the quite old Ottoman residential area of Izmir, Turkey. The city is situated on the west coast of the country, next to the Aegean Sea, and thus has a Mediterranean climate; summers are hot and humid, while winters are mild and rainy. The Basmane District constitutes a considerable part of the Kemeraltı Urban Historical Site within the historic urban residential texture. 1273 Street, as the selected neighborhood, is in a residential zone which hosts qualified historic buildings within Basmane District. It lies on the east–west direction with a 38.25◦ N latitude and a 27.08◦ E longitude and is 12 m elevation above the sea level. The neighborhood has a key position due to its proximity to Basmane Historic Train Station, Agios Voukolos Church and the Altınpark Archaeological Excavation Area of the antique Smyrna City. In the last decade, it has been mostly populated by transboundary migrants, especially Syrian refugees, as the temporary residential area. The historic urban fabric of neighborhood has been damaged.

Izmir Metropolitan Municipality prepared the Façade Rehabilitation Project for 1273 Street in 2013 to regenerate the neighborhood, requiring intervention strategies for improving security and rehabilitating living conditions. In addition, the municipal boards wanted to interfere with the existing conditions, at least, to improve pedestrian routes for local and foreign tourists. However, any energy-efficient approach was not considered during the rehabilitation process. Therefore, this study has been prepared as a proposal for Izmir Metropolitan Municipality to provide local, applicable and quick retrofit solutions with the most energy saving potential within the limited project budget.

A total of 22 buildings, covering historic and contemporary buildings which lie on 1273 Street, are investigated (Figure 1). There are 4 solely commercial and 18 residential buildings, 3 of which have shops on their ground floors. Both historic and contemporary buildings coexist in the street, situated in adjacently. Of the 22 buildings, 13 are historic ones, in total: 11 of them are officially registered, while the remaining 2 are determined as non-registered in character. The rest are the contemporary buildings. The number of floors varies between one and three. A large majority of extant historic buildings were built between the end of 19th and the first quarter of 20th centuries. A total of 20 buildings were constructed with stone or a brick masonry system. There are only two reinforced concrete buildings. The oriels on the second floors designed as a protrusion with wooden or iron structure, ornamentations on iron doors and stone wall order are typical periodic characteristics of historic buildings (Figure 2).

A total of 22 buildings, covering historic and contemporary buildings which lie on 1273 Street, are investigated (Figure 1). There are 4 solely commercial and 18 residential buildings, 3 of which have shops on their ground floors. Both historic and contemporary buildings coexist in the street, situated in adjacently. Of the 22 buildings, 13 are historic ones, in total: 11 of them are officially registered, while the remaining 2 are determined as non-registered in character. The rest are the contemporary buildings. The number of floors varies between one and three. A large majority of extant historic buildings were built between the end of 19th and the first quarter of 20th centuries. A total of 20 buildings were constructed with stone or a brick masonry system. There are only two reinforced concrete buildings. The oriels on the second floors designed as a protrusion with wooden

A total of 22 buildings, covering historic and contemporary buildings which lie on 1273 Street, are investigated (Figure 1). There are 4 solely commercial and 18 residential buildings, 3 of which have shops on their ground floors. Both historic and contemporary buildings coexist in the street, situated in adjacently. Of the 22 buildings, 13 are historic ones, in total: 11 of them are officially registered, while the remaining 2 are determined as non-registered in character. The rest are the contemporary buildings. The number of floors varies between one and three. A large majority of extant historic buildings were built between the end of 19th and the first quarter of 20th centuries. A total of 20 buildings were constructed with stone or a brick masonry system. There are only two reinforced concrete buildings. The oriels on the second floors designed as a protrusion with wooden

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**Figure 1.** Numbered case buildings in 1273 Street. Source: modified from the drawings of Konak Municipality. **Figure 1.** Numbered case buildings in 1273 Street. Source: modified from the drawings of Konak Municipality. **Figure 1.** Numbered case buildings in 1273 Street. Source: modified from the drawings of Konak Municipality.

**Figure 2.** View from 1273 Street. **Figure 2. Figure 2.** View from 1273 Street. View from 1273 Street.

#### **3. Materials and Methods**

This study proposes a method to develop retrofit strategies about the energy efficiency of existing buildings in historic urban district, including both historic and new buildings via appropriate solutions only for the buildings' envelopes. The retrofit strategy considers the impact assessment criteria and scale of retrofit measures for historic buildings, presented by a five-level assessment scale of EN 16883:2017 [21].

The identification process of retrofit strategies is composed of seven main stages: data collecting, data processing, creating possible retrofit solutions, categorizing buildings, assessing retrofit solutions, analyzing data and presenting results (Figure 3). This method starts with the quick field survey, i.e., data collection conducted in several levels. First, documents about the case area are obtained to

investigations.

get preliminary information. The data sheets are created to characterize of the buildings in the case area. Then, on-site measurements on the buildings' envelope are carried out through data sheets. Additionally, it is attempted to get information about the buildings in use from the users of buildings. *Atmosphere* **2020**, *11*, x FOR PEER REVIEW 5 of 33

**Figure 3.** Identification process of energy-efficient retrofit strategies. **Figure 3.** Identification process of energy-efficient retrofit strategies.

*3.1. Data Collection*  Data collection, aiming to gather the required adequate and reliable information about buildings' envelope through a quick survey, is composed of two steps: pre-study and field survey. The former includes the collection of any research and official documentation about case area and buildings. The latter is mainly grouped under site investigations: creating data sheets, conducting on-site measurements for components of buildings' envelopes and interviews with the buildings' users. Data collection was held in two separate time periods of 20–25, June, 2014 and 10–15, February, 2016. Documentation about the case area and its surrounding were obtained from the Street The second stage continues with the characterization of the tool selected to put in the process of the method and explanation of how they work. The case area is modelled in dynamic simulation software to calculate the energy consumption of the case buildings in existing conditions. This building performance simulation (BPS) model represents the base model of case buildings. The next three stages lay emphasis on the energy-efficient retrofit strategy for the case buildings. Accordingly, the third stage discusses and presents possible energy-efficient solutions for the retrofitting of existing buildings, covering new and historic ones. It primarily concerns the retrofit solutions of the components of buildings' envelopes, including external walls, floors, roofs, oriels, windows and doors. The fourth stage goes forward with the categorization of case buildings considering the heritage value.

Rehabilitation Project Proposal of Izmir-Konak Municipality held in 2013. Particularly for historic buildings, inventory forms of 11 officially registered buildings were provided by the Izmir Metropolitan Municipality Directorate of Historic Environment and Cultural Properties. These forms provide information about the degree of protection status of historic buildings; they do not include any construction drawings and details. Except for three registered buildings, the architectural drawings, such as floor plans and sections of the buildings, were not reached during the site The fifth stage aims at deciding possible packages of retrofit solutions to provide energy savings. It presents the most appropriate solutions and eliminates the inappropriate ones for the categorized case buildings. Therefore, a five-level impact assessment scale for retrofit solutions is investigated for historic buildings. In the sixth stage, new building performance models for retrofit solutions are created and simulated for each retrofit package. After a comparative study between the base case simulation results and retrofitted ones, the relationships between annual energy consumptions and

e.g., physical (envelope) qualities, construction details and surrounding features. The type of data

design parameters are presented. In the seventh stage, possible retrofit strategies for the case buildings are introduced.

#### *3.1. Data Collection*

Data collection, aiming to gather the required adequate and reliable information about buildings' envelope through a quick survey, is composed of two steps: pre-study and field survey. The former includes the collection of any research and official documentation about case area and buildings. The latter is mainly grouped under site investigations: creating data sheets, conducting on-site measurements for components of buildings' envelopes and interviews with the buildings' users. Data collection was held in two separate time periods of 20–25 June 2014 and 10–15 February 2016.

Documentation about the case area and its surrounding were obtained from the Street Rehabilitation Project Proposal of Izmir-Konak Municipality held in 2013. Particularly for historic buildings, inventory forms of 11 officially registered buildings were provided by the Izmir Metropolitan Municipality Directorate of Historic Environment and Cultural Properties. These forms provide information about the degree of protection status of historic buildings; they do not include any construction drawings and details. Except for three registered buildings, the architectural drawings, such as floor plans and sections of the buildings, were not reached during the site investigations.

Data sheets, composed of a double-sided page in A4 format, were prepared for each building in the case area. The aim was to characterize the current status (historic/old/new) of the case buildings, e.g., physical (envelope) qualities, construction details and surrounding features. The type of data about building envelope and surrounding required by BPS model were determined. Observation, measurements and photography techniques were used in collecting required data for the data sheets.

On-site measurements were carried out for external walls, floors, roofs, oriels, windows, external doors and shutters to characterize construction materials with simple sections, elevations and plan drawings. Dimensions of the structural components were identified via a laser distance meter and then noted on the relevant section in the data sheets. Moreover, the height and width of surrounding buildings were measured by laser distance meter to identify the adiabatic surfaces of the adjacent neighboring buildings and their shading effect. Through the measurements, the following specifications about the envelope are clarified and corrected:


Moreover, traditional building material samples collected from immediate environment were tested to determine their thermal properties. The thermal conductivity (W/mK) of various stone and solid brick samples was measured by the Quick Thermal Conductivity Meter (KEM Q500 with a measuring range of 0.023 to 12 W/mK and a precision of ±5% reading value per reference plate) [40] in the Geothermal Energy Research and Application Centre of Izmir Institute of Technology (IZTECH JEOMER).

Short interviews with the occupants of several buildings were conducted in order to obtain adequate information about the case buildings, i.e., the purpose of use, number of occupants/users, user profile, construction date, how the buildings are heated and cooled and type of fuel used.

JEOMER).

#### *3.2. Data Processing 3.2. Data Processing*

## 3.2.1. BPS Model

A reliable and verified building performance simulation (BPS) software, DesignBuilder v.5.2, was used for model creation, energy simulation and analysis, as well as decision-making processes [41]. Model creation of the case buildings was prepared according to the most recent field survey which was completed in 2016 (Figure 4). Through data processing, the base case models, which indicate the real status of each case building, and then the retrofitted case models to assess the energy-efficient retrofit solutions were prepared. Seasonal energy consumption for heating and cooling and annual energy consumption were analyzed. The model geometry of case buildings was simplified in line with the purpose of the study: identification of strategies for energy-efficient retrofit via quick field survey. The model abstraction was conducted for both the façades and layout plans of buildings. 3.2.1. BPS Model A reliable and verified building performance simulation (BPS) software, DesignBuilder v.5.2, was used for model creation, energy simulation and analysis, as well as decision-making processes [41]. Model creation of the case buildings was prepared according to the most recent field survey which was completed in 2016 (Figure 4). Through data processing, the base case models, which indicate the real status of each case building, and then the retrofitted case models to assess the energy-efficient retrofit solutions were prepared. Seasonal energy consumption for heating and cooling and annual energy consumption were analyzed. The model geometry of case buildings was simplified in line with the purpose of the study: identification of strategies for energy-efficient retrofit via quick field survey. The model abstraction was conducted for both the façades and layout plans of buildings.

user profile, construction date, how the buildings are heated and cooled and type of fuel used.

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about building envelope and surrounding required by BPS model were determined. Observation, measurements and photography techniques were used in collecting required data for the data sheets. On-site measurements were carried out for external walls, floors, roofs, oriels, windows, external doors and shutters to characterize construction materials with simple sections, elevations and plan drawings. Dimensions of the structural components were identified via a laser distance meter and then noted on the relevant section in the data sheets. Moreover, the height and width of surrounding buildings were measured by laser distance meter to identify the adiabatic surfaces of the adjacent neighboring buildings and their shading effect. Through the measurements, the following

• width**–**length of the external floors (external floor below the oriels and external floor over the

Moreover, traditional building material samples collected from immediate environment were tested to determine their thermal properties. The thermal conductivity (W/mK) of various stone and solid brick samples was measured by the Quick Thermal Conductivity Meter (KEM Q500 with a measuring range of 0.023 to 12 W/mK and a precision of ±5% reading value per reference plate) [40] in the Geothermal Energy Research and Application Centre of Izmir Institute of Technology (IZTECH

• width**–**length**–**height of the windows and their position on the external wall surfaces; • width**–**length**–**height of external doors and their position on the external wall surfaces;

specifications about the envelope are clarified and corrected:

• width**–**length**–**height of the external walls;

entrances designed as a door niche);

• width**–**length**–**height of the oriels; • width**–**length**–**height of the shutters; • width and length of the eaves of the roofs.

**Figure 4.** Model of case buildings and their surrounding from the (**a**) south and (**b**) north direction in DesignBuilder Software. **Figure 4.** Model of case buildings and their surrounding from the (**a**) south and (**b**) north direction in DesignBuilder Software.
