**1. Introduction**

Generally, people spend more than 60% of their time in domestic indoor environments [1]. In the domestic setting, occupants' living experiences and household activities are diverse in every step of their daily lives and there are numerous preferences related to occupants' spatial needs and demands [2–4]. These preferences are connected to multiple aspects of domestic settings and are perceived through occupants' living experiences. Every component of the domestic environment has a negative or positive impact on occupants' psychological responses. Several studies also identified that these factors stimulate humans' mediative capacities in their living environments [5]. Therefore, it is necessary to explore occupants' perceptions and living experiences in domestic settings to enhance their mental wellbeing [6]. Domestic environmental experience generally indicates users' experiences of cognitive perceptions and physical responses in domestic settings [6]. The environmental design concept may be enriched by integrating rigorous perceptions and systematic data associated with occupants' experiences in different spaces of the built environment [7].

**Citation:** Chowdhury, S.; Noguchi, M.; Doloi, H. Conceptual Parametric Relationship for Occupants' Domestic Environmental Experience. *Sustainability* **2021**, *13*, 2982. https:// doi.org/10.3390/su13052982

Academic Editor: András Reith

Received: 14 February 2021 Accepted: 4 March 2021 Published: 9 March 2021

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The literature has identified that the domestic environment serves various purposes and has meaningfulness related to occupants' spatial and environmental aspects. A domestic setting generally has different spatial zone distributions. Each area has specific characteristics related to its spatial and environmental factors that affect occupants' physical and psychological wellbeing in living environments [6]. Thus, every domestic component has a significant spatial and environmental relationship that may enhance occupants' emotions [6,8,9]. These spatial and environmental factors may vary from one space to another, associated with occupants' multidimensional preferences (e.g., needs and demands) [6]. Consequently, the valuation of these factors is critical in designing domestic environments according to different living spaces. However, without a clear perception of occupants' spatial and environmental experiences of different areas in a domestic setting, it is difficult to identify overall environmental design solutions to enhance their mental wellbeing.

This study has been conducted using a comprehensive literature review based on occupants' domestic environments and their household experiences. Various aspects of occupants' spatial and environmental experiences in domestic settings have been elaborated in this study. This study's primary research question is "*What is the theoretical parametric relationship for occupants' domestic environmental experiences that enhance their wellbeing?*" This study's main objective is to explore the theoretical parametric relationship between occupants' spatial and environmental design factors through the household experience of different areas in domestic settings that may stimulate occupants' quality of life. To develop a conceptual framework or associations to identify a correlation among various spatial and environmental design factors in a domestic setting, emphasising space-wise household experiences is the primary focus of this study.

#### **2. Literature Selection Criteria and Research Methods**

A literature review is a pedagogical study linked to a particular theme or research question [10,11]. Several studies found significant impacts of domestic environments on human perceptions [1,6,8,12]. This study explores theoretical relationships of different domestic spaces between spatial and environmental design factors through occupants' household experiences based on the literature, which may stimulate living quality. The study was conducted using a comprehensive background of 30 keywords based on occupants' domestic environments and their household experiences. The keywords encompassed domestic environment and occupants' experiences as well as a diversity of psychological and behavioral aspects related to residential settings (Figure 1). "Human Perception and Phenomenology, Environmental Design and Psychology, Residential Environment and Design, Health and Wellbeing and User Experience" are the main thematic study areas that were considered to explore occupants' spatial and environmental experiences in domestic settings in this study.

The following 30 keywords associated with the thematic study domains have been used: domestic environment, housing, dwelling, home, occupant experiences, occupant spatial experiences, occupant environmental experiences, household activities, high rise residential apartment, dwelling environment, apartment building, residential function, household functions and activities, space use behavior, occupant psychology, occupant behavior, residential comfort, residential satisfaction, indoor environment, environmental quality, mental wellbeing, physical environment, post-occupancy evaluation, human perception and phenomenology, ecological design, human emotions, feelings and moods, consumer behavior, user experience, and product user experience.

This study is limited to scholarly research articles published between 1970 and 2020. An extensive data search was conducted using a combination of different keywords related to domestic environmental experiences through Scopus, Science-Direct and PubMed databases to categorise relevant studies based on the research theme, titles, abstracts, keywords and findings that fell into the thematic study areas. Supplemental cross-searches were also conducted through Google Scholar, Mendeley, Research Gate and other academic search engines. All the literature referring to the domestic environment and occupants' psychological or behavioral experiences in residential buildings in their title, abstract or keywords were categorised for screening. The collected studies were separated according to the following five criteria: (a) focus on the domestic environment and occupant perception, (b) occupant experiences in different spaces of a domestic environment, (c) environmental design and occupant's psychology in a domestic setting, (d) human factors in built environments, and (e) peer-review. After the final screening, duplicate and nonrelevant studies were omitted from the selection and the significant relevant references list was formed according to this study's scope and limitation.

**Figure 1.** Literature selection strategies and research methods.

The following sections first analyse the background to spatial and environmental design factors regarding occupants' experiences. It then analyses these according to the different spaces of a domestic environment based on the literature. The review provides a systematic and comprehensive assessment of the domestic environment and occupants' experiences regarding spatial and environmental design aspects to enrich the state-of-theart of existing knowledge and explore the potential for future investigations into "*Domestic Environmental Experience Design*".

#### **3. Theoretical Background**

This literature review mainly explores the theoretical relationships between spatial and environmental design factors in the domestic living environment, addressing occupants' wellbeing. In this study, the component considering perceived spatial factors focuses on users' spatial experiences linked to user preferences (needs and demands) in their living environments. The other component, which concerns the environmental design factors, deals with architectural design elements primarily related to indoor environmental physical design aspects. It also encompasses not only indoor environmental qualities but also the psychological aspect of occupants' feelings. In the following sections, space-related user preferences (spatial factors) and environmental design components (environmental factors) were elaborated through the literature to explore the theoretical parametric relationship in occupants' experiences in their domestic living environments.

#### *3.1. Spatial Factors for Occupants' Experiences*

McClure et al. mentioned seven domains: "products, interiors, structures, landscapes, cities, regions and earth" in the built environment. Every field has its own identity and these identities closely correlate to each other. The domestic environment design reflects interior and structure domains as part of the total built environment [13]. Additionally, indoor architecture's history suggests that human social, psychological and physical perceptions attach numerous qualities of living to environments, where the core concern is human scale and performance [14]. According to Blossom, human nature has two characteristics, functional and behavior; thus, designers need to realise how the built environmental design element affects individual perception, considering psychological aspects, for the different zones, as Hall mentioned [14].

Philosophically, space reflects human perceptions of physical existence. According to the earliest theoretical perspective of space, perception reflects the human-centric dimension. German philosopher August Schmarsow addressed the spatial interaction of beings with the world and quoted space as a place for physical and mental projection [2]. Further, Edward T. Hall, founder of the study of anthropological space named "Proxemics," in the book "The Hidden Dimension", mentioned the relationship between spatial setting and human beings [2]. According to environmental psychology, human beings always interact and perceive their immediate environments by sensory dimensions such as smell, vision, touch, hearing, haptic and kinesthesia [14]. When experiencing a space or place, sensory organs play a fundamental role for a human being. In that sense, spatial design attributes impact human perceptions in numerous ways within the total built environments [2,5].

Again, the literature review shows that place-attachment theory is a vital perception and the core concept of environmental psychology which affects people and places [15]. Human beings create a robust understanding of place attachment within their immediate environment, which supports physical and psychological wellbeing [16]. Place attachment is the personal interaction with the environment and the central concept of human emotional responses [16]. According to Stedman, an individual's satisfaction is another element of place attachment, which defines the value of meeting basic human needs in a living environment [15]. Stokols describes "Home" as a dwelling place where individuals can fulfill their psychological, physical and social needs to keep themselves connected [17]. Seemingly, Hayward emphasised psychological concepts, with significance given to privacy, identity, socialisation, continuity and personalisation, as a home attachment [18]. Dovey highlighted the phenomenon of "Home" considering three themes: order, identification and dialectic processes, in the article entitled "Home and Homelessness" [19].

While most home environmental studies begin with people who already live in a home and deal with satisfaction, Rapoport identified a previous question about how they reach this point. Rapoport observed that the consequence of the environment was addressed improperly. In reality, the near environment's real effect on a human being is habitat selection according to their needs and preferences [20]. In the meantime, Pennartz described the home atmosphere as focusing on communication, accessibility, relaxation and individual experiences [21]. Mallett addressed the notion of "Home" in an article entitled "Understanding Home: A Critical Review of the Literature" considering people's relationship with spaces and objects. Home is a dwelling interaction space between people, places and things associated with a comfortable feeling, intimacy, security, relaxation and persecution [22]. The importance of human needs and spatial hierarchy, such as territoriality, physical and psychological comfort, privacy and function, provide the designer with an understanding of human nature and satisfaction [13].

In a nutshell, "Home" as a domestic setting indicates varied meaningfulness, functions, purposes and aims. Human needs include identity, control, security, privacy, order, variety, sociability, aesthetics and choice, integrated into environmental psychology and interpreted by human experiences (Figure 2) [5,23]. However, it is critical to understand the assessing and prioritising of these human physical and psychological needs [2]. In short, the domestic

experience is a medium that may connect occupants' needs and demands with their living environments.

**Figure 2.** Relationship between spatial factors and occupants' response. Here, the sign (*±*) indicates adding/decreasing the number of factors according to user needs and demands. (Illustration: Author, based on literature)

#### *3.2. Environmental Factors for Occupants' Experiences*

The domestic setting has indoor and outdoor environmental characteristics that reflect occupants' spatial needs and demands in their living environments. Several studies indicate that each design element directly or indirectly impacts the occupants' overall physical and psychological wellbeing [16]. Several studies focusing on indoor environmental conditions such as noise, lighting, material, air, odors and color; conclude that environmental psychology bridges design and human response at the indoor environment scale.

Kaplan's "Attention Restoration Theory (ART)" proposed a framework that differentiates between stress and attentional components of human experiences in their environments. Emphasising the critical role of natural environments, this integration contributes towards human-environment interaction. According to Kaplan, experiencing a natural environment reduces human stress [24]. In addition, Ulrich's "Stress Reduction Theory (SRT)", focusing on the role of nature in wellbeing, indicates an evolutionary perspective that suggests that natural experiences have an immediate benefit on human mental wellbeing. Ulrich emphasises affective and aesthetic human responses to the natural environment [25]. Both Kaplan and Ulrich identify natural settings or environments as stimulating components for human wellbeing in numerous ways.

In the book entitled "A Home for the soul: a guide for dwelling with spirit and imagination", Lawlor describes the interaction of human emotions and feelings with architectural design components based on human spiritual perceptions in their dwelling environments [26]. Lawlor also discussed interconnectedness and perception of human cognition and architectural design elements such as earth, fire, air, space and water, as five spiritual elements, through human experiences in their dwelling environments. Consequently, Lawlor reveals how the eight fundamental building elements of architecture can be related to different aspects of human thinking and feeling. The author mainly explores everyday household traditions and symbolism, rather than exploring dwellers' situational or practical experiences with restrictions or limitations.

Furthermore, Evans argues that every element of the built environment directly or indirectly affects occupants' mental health [8]. According to Evans, most research on housing focused mainly on physical health. Nonetheless, different house types (e.g., highrise)

and housing quality impact occupants' mental wellness. Evans identified that the natural environment affects occupants' psychological perceptions in highrise residential environments [8]. Poor quality of housing and indoor environments increases the negative impact of psychological stress and illness. Still, this is not enough to draw a clear methodological perception and conclusion.

Ergan et al. examined that occupants' emotional reactions to color, light, noise, air quality and crowding are distinctive and momentary in the living environment [27]. Levels of illumination, pollution and daylight exposure affect occupants' psychological wellbeing in numerous ways [8,28]. Several studies and randomised experiments are prioritised to evaluate the physical environment's potential role in occupants' mental wellbeing. As Evan stated, some methodological problems may create conflicting prejudice, triggering the undervaluation of housing–wellbeing associations. The author noted that ambient environmental interactions with architectural components positively impact human physical, biological and psychological aspects [28]. For instance, noise affects users' privacy, while smell impacts human memory [28]. Meanwhile, indoor lighting variation also affects and triggers human moods, feelings and psychological growth [28].

Moreover, other studies also describe that features of different domestic spaces, such as the bedroom, kitchen, dining, living, toilet, game room, gues<sup>t</sup> room, gues<sup>t</sup> bath, study, media room, entrance, utility room, backyard and garage, stimulate occupants' daily household activities and interact with emotional states [9,29]. In contrast, crowded enclosed spaces with no ventilation increase personal psychological stress, while space adjustability decreases mental stress [9]. Other services and utility facilities also impact the occupants' mental satisfaction in the residential environment [2]. Seemingly, spatial ergonomics also affect usability and occupants' emotional perceptions, such as relaxation and pleasantness within domestic environments [2].

According to Amérigo and Aragones' interpretation, domestic satisfaction is essential for the quality of life and indoor environment elements can stimulate human feelings [30]. In their research, a theoretical approach was applied to explore a general view of a person's satisfaction within a residential environment and a conceptual framework of individual interaction in a residential setting was presented. They developed an empirical model of residential satisfaction; a question arises regarding the trustworthy dimensions for residential pleasure or happiness, which might direct future environmental research on domestic settings. However, the concept of residential quality integrating different human factors and occupants' comfortable domestic environments indicates a direction for future research [30]. Considering the literature reviewed, the environmental experience is a multilayered phenomenon requiring different kinds of sensory involvement and interaction. The domestic environment influences occupants' wellbeing and needs to accommodate occupants' daily household activities. As discussed above, the synthesis of previous research studies leads to major categories of human experiences in various architectural design spaces. The literature gap still exists in the understanding of how spatial and environmental design features impact occupants' experiences in different spaces of domestic settings according to their household activities.

In Figure 3, a conceptual relationship is derived from the literature describing the environmental factors that contribute to stimulating occupants' emotions in their domestic environments [6,23].

**Figure 3.** Relationship between environmental factors and occupants' response. Here, the sign (*±*) indicates adding/decreasing the number of factors according to user needs and demands. (Illustration: Author, based on the literature).

#### **4. Domestic Spaces and Occupants' Experiences**

#### *4.1. Domestic Environment and Its Functional Aspect*

Several psychological and phenomenological studies have been conducted to define the meaning of "Home" as a domestic environment [31]. According to Pallasmaa, the phenomenology of "Home" is not just an architectural effort. It has an aesthetic view, considering physical, psychological and sociocultural phenomenon. Pallasmaa believes that "Home" has multilayered characteristics, integrating memories, desires, intimacy, privacy, identity, function and even language [32]. Continuing this exploration, the domestic environment becomes an essential feature of "Self-identification" for peoples, where privacy, comfort and domesticity are the occupants' core achievements [31,33]. Moore and Caan described their views within psychological and sociological debates: domestic environments reflect numerous human behaviors and preferences because of different physical, psychological and social contextual human experiences. These experiences are essential to mediating tangible and intangible design aspects in the living environment [2,31]. Considering several studies, the term "*Domestic Environmental Experience*" was defined briefly as user experiences of cognitive perceptions and physical responses to their domestic built environment with a diversity of daily household activities [6]. In short, domestic environmental experience connects occupants' physical, psychological and social needs and demands, correlated with different factors of the built environment, such as spatial and environmental factors.

The above literature identified that the domestic environment has various purposes, meaningfulness and aims related to occupants' different spatial and environmental aspects. A domestic setting generally has mainly three types of spatial zones distribution. For example, private areas (e.g., bedroom, study, attached toilet and balcony), used independently by family members only; semi-private areas (e.g., family space, kitchen space, dining room, storage, utility and prayer room), commonly used by only family members; and public areas (e.g., foyer, living room, gues<sup>t</sup> room, balcony and powder room), used by guests beyond family members [6]. It has also been identified that these indoor spatial arrangements can be connected with external additions, such as a balcony, garden and porch, which fall into private, semi-private or public spaces [6]. A domestic setting is interconnected with its different areas, for example, the kitchen has close connectivity with the dining space. The gues<sup>t</sup> room, toilet and dining room have a positive relationship

with the living room. Each area also has spatial characteristics related to environmental design factors that accelerate occupants' physical and mental wellbeing in living circumstances [6,9]. Thus, every indoor area of the domestic environment has a significant spatial and environmental relationship that may enhance occupants' psychological responses. These factors, in the domestic setting, are associated with occupants' needs and demands and vary from space to space; they are elaborated below according to the literature.
