Strategic Biophilic Residential Design Based on Seniors’ Health Profiles: A HRQoL-Driven Approach

Abstract

This study aims to develop a strategic framework for biophilic residential design (BRD) tailored to the diverse health profiles of seniors. To achieve this, a nationwide survey of 424 seniors in South Korea was conducted to assess their health-related quality of life (HRQoL) and preferences for BRD elements. Through principal component and cluster analyses, three HRQoL dimensions—social-economic, mental-sensory, and physical QoL—were extracted, and four distinct senior clusters were identified: Optimal Health, Physically Declining, Overall Low Health, and Socially Vulnerable. Statistically significant differences in BRD preferences were found across clusters for 11 out of 28 BRD elements (p < 0.05), particularly in categories related to sensory-based physiological stability, cognitive stimulation, and external-social connectivity. Notably, the Physically Declining Group expressed a strong preference for restorative and stable features (e.g., natural colors and ventilation systems), while the Socially Vulnerable Group prioritized elements promoting external interaction and social engagement (e.g., balconies, indoor gardens, and walkways). Based on these results, BRD elements were reclassified by function and mapped to the spatial needs of each cluster, leading to a strategic design matrix that supports adaptive and user-centered residential planning. This HRQoL-driven framework contributes a novel link between multidimensional health diagnostics and biophilic design application, moving beyond generalized aging-in-place models. The findings offer practical insights by linking BRD strategies to distinct health profiles. For practitioners, the matrix can inform spatial layouts and design priorities. For policymakers, it provides a basis for developing differentiated housing standards aligned with seniors’ health conditions.

1. Introduction

1.1. Background

The “senior shift” concept reflects a demographic transformation in which older adults are becoming a central focus across various sectors—including the economy, industry, and public policy—due to the rapid acceleration of population aging. This shift has catalyzed the segmentation of the silver market, driving the development of personalized strategies that address the diverse needs of aging populations. As seniors’ economic and cultural capital increases, their expectations extend beyond mere care in later life; instead, they seek environments that enable psychological stability and the maintenance of meaningful social relationships. Consequently, the focus of senior housing planning has shifted from passive care to enhancing quality of life (QoL).

The senescent period is characterized by complex functional declines that may not necessarily be classified as diseases but lead to various biological discomforts [1,2]. Often, seniors endure prolonged periods of psychological and social distress that remain unrecognized and unaddressed, particularly when not medically diagnosed [3]. These vulnerabilities are exacerbated by both psychosocial and physical environmental factors. Seniors are often less capable of adapting to or coping with negative environments, increasing their risk of experiencing physical injuries and emotional insecurity within their homes [4]. Thus, residential environments must be designed to mitigate these negative influences and support seniors’ health-related quality of life (HRQoL).

Biophilic design—which incorporates natural elements into the built environment—is widely recognized for its positive effects on well-being. Prior research suggests that exposure to natural features can reduce stress [5,6,7], enhance cognitive functioning [8,9,10], and lead to improved overall health outcomes [11]. However, the benefits of biophilic environments are not universally experienced, as individual responses vary considerably. These differences are often shaped by personal preferences, which are themselves influenced by one’s sociocultural background and health status [12,13,14,15]. Exposure to preferred natural elements can amplify both physical and psychological restorative effects [15,16,17,18]. Environments that reflect these preferences reinforce individual motivation to interact with nature [19], thereby fostering more meaningful and positive experiences.

Despite growing interest in biophilic design for older adults, limited attention has been paid to how seniors’ HRQoL profiles shape their preferences for such environments. Most existing research focuses on short-term therapeutic effects, particularly among individuals with dementia or clinical conditions [20]. Moreover, macro-level approaches to nature and health have made it difficult to identify or categorize optimal biophilic design elements based on individual health profiles [21]. To address this limitation, it is essential to analyze the relationship between seniors’ HRQoL profiles and their preferences for biophilic residential design (BRD), as this is crucial for creating long-term health-responsive environments for independent older adults.

However, although the general benefits of biophilic design for older adults have been broadly acknowledged in the literature, many studies have treated seniors as a relatively uniform group. This tendency overlooks the diversity of aging experiences, particularly the varying physical, cognitive, and social health conditions that shape design needs. This study responds to that gap by introducing a differentiated approach based on HRQoL.

1.2. Research Aim and Research Questions

This study aims to identify the diverse spatial needs of older adults based on their HRQoL profiles and to propose functional health-responsive design strategies by linking these needs to BRD elements. The study explores the following research questions:

• RQ1. How do senior individuals’ HRQoL profiles influence their preferences for biophilic residential design elements?
• RQ2. How can biophilic design elements be functionally categorized and matched to residential spatial needs according to each senior HRQoL profile?
• RQ3. What are effective strategic design interventions that reflect seniors’ HRQoL and BRD needs?

2. Literature Review

2.1. Seniors’ HRQoL and Residential Environment

The concept of HRQoL has been extensively examined across a wide range of disciplines, including public health, psychology, and environmental sciences. HRQoL focuses on how an individual’s health status influences their daily life and overall life satisfaction [22,23]. Aging is accompanied by physiological, psychological, and social changes that collectively impact personal well-being. Accordingly, HRQoL assessments for seniors typically encompass physical health, mental well-being, and social functioning [24]. To identify the assessment domains for evaluating HRQoL among older adults, this study reviewed major standardized HRQoL scales [25,26,27,28] as well as related empirical studies [29,30,31,32,33]. A summary of the identified domains is presented in

Table 1. Identified key domains of HRQoL.

HRQoL Assessment Items	Details
Functional mobility	Limitations in physical movements such as standing up, sitting down, or climbing stairs.
Ability to perform daily activities	Restrictions in daily activities such as work, studying, or housework.
Pain and discomfort	Limitations caused by physical pain, discomfort, or heartburn.
Sensory function	Limitations due to impaired sensory functions such as vision and hearing.
Anxiety and depression	Restrictions due to feelings of depression and anxiety.
Quality of sleep	Limitations due to insufficient sleep duration and poor sleep quality.
Cognitive function and memory	Limitations in recognizing objects and people or recalling familiar information.
Hobbies and leisure activities	Restrictions on engaging in hobbies, leisure activities, or travel.
Social relationships	Level of physical and emotional closeness with family and peers.
Productive activities	Limitations related to productive activities or economic circumstances.

.

HRQoL among seniors is evaluated across 10 core domains. These domains are closely linked to the residential environment, which plays both a direct and indirect role in maintaining independence, supporting life satisfaction, and facilitating social interaction [22]. Physical aspects of the residential environment are particularly relevant to age-related declines in functional capacity. Key design considerations include the provision of safe and familiar spatial layouts, accessible furnishings, and well-planned lighting schemes that promote physical comfort and reduce injury risk [34,35]. Psychological factors are shaped by the extent to which the environment offers multi-sensory stimulation that aligns with seniors’ specific needs. Such stimuli contribute to emotional stability and help preserve cognitive functioning [36,37]. Social dimensions of HRQoL are supported through communal activities and opportunities for interpersonal engagement within the living environment. These features reduce feelings of isolation and enhance subjective well-being among older adults [15,38].

2.2. Biophilia and Biophilic Design

2.2.1. Biophilia: Preference for Nature

The human preference for nature is rooted in our evolutionary adaptation to natural environments, which were historically perceived as favorable for survival [39,40,41]. This evolutionary perspective provides a foundation for understanding humans’ positive physiological and psychological responses when exposed to natural stimuli. Biophilia refers to the innate human tendency to seek connections with living organisms and natural systems [42]. According to the biophilia hypothesis, activating one’s internal biophilic tendencies can promote well-being, enhance emotional stability, and improve cognitive and behavioral performance [43]. Observing living organisms and feeling connected to their biological rhythms is associated with essential psychological responses contributing to human flourishing [44].

Its primary goal is to enhance occupants’ well-being through deliberate integration of natural elements [14]. However, biophilic tendencies manifest in more conscious and diverse forms in contemporary contexts marked by urbanization and rapid technological advancement [45]. Empirical studies have demonstrated that exposure to natural elements, particularly those that align with individual preferences, can significantly improve mental restoration, reduce stress, and support health outcomes [46,47]. However, the implementation of biophilic elements without regard for user-specific needs may result in limited or negligible effects [15,48]. This disconnect often leads to unequal biophilic experiences, highlighting a growing concern that many current biophilic environments fail to adequately address user diversity in preference and perception [49].

2.2.2. Theoretical Frameworks of Biophilic Design

Studies [44,48,50,51,52,53,54] that presented the theoretical framework of biophilic design emphasize the need for three categories to integrate nature and architecture. The first category highlights the essential characteristics of natural environments, focusing on the direct use or incorporation of elements such as water, plants, and sunlight into architectural spaces. The second refers to mimicking or symbolically representing natural forms and patterns. The third highlights the contextual and spatial characteristics of nature, including the sense of place and environmental coherence.

Two leading theoretical contributions have shaped the conceptual foundation of biophilic design, as illustrated in Figure 1. This study adopts an integrated theoretical approach, referencing both Kellert’s experiential model [55] and Browning, Ryan, and Clancy’s functional patterns model [51]. These two perspectives are complementary: Kellert’s model facilitates the categorization of biophilic elements based on users’ lived experiences, whereas Browning et al.’s model provides a pragmatic lens for interpreting their functional roles within spatial contexts.

Kellert [55] proposed a model consisting of 25 attributes across three experiential dimensions: direct experience, indirect experience, and experience of space and place. This model was prioritized as the primary theoretical framework because these dimensions reflect how individuals physically, mentally, and socially engage with their environments. These experiential categories closely correspond to the key components of HRQoL, such as physical comfort, cognitive stimulation, and social connectedness, which form the basis of this study’s user profiling approach.

In contrast, Browning, Ryan and Clancy [51] identified 14 patterns across three categories for designing the functional properties of nature in a spatial context. This model provides a clearer operational basis for translating empirical biophilic attributes into detailed residential planning strategies.

2.3. Biophilic Design Experience for Seniors

To examine current practices in biophilic design for seniors, this study conducted a literature review organized around the three experiential categories outlined in Figure 2. Between 2019 and 2023, research on biophilic design for seniors has grown noticeably, a trend that coincides with increased attention to indoor environmental quality in the wake of the COVID-19 pandemic [56,57]. Despite this growing interest, the majority of studies remain concentrated in healthcare and medical facility contexts. This indicates a notable gap in research addressing biophilic interventions within senior residential environments. While the direct experience of nature remains a consistent area of scholarly attention, the experience of space and place, particularly in residential contexts, remains underexplored. Nonetheless, there has been a recent shift toward more integrated approaches that encompass all three biophilic dimensions. Recent studies emphasize that these three categories are not mutually exclusive but function as complementary components of a unified design approach [58]. In particular, designs that combine direct interaction with natural elements, sensory-oriented indirect cues, and spatial or contextual features tend to yield greater benefits for health and psychological well-being [51,55].

Direct experience with nature is particularly important for supporting the physical and psychological health of older adults. Small-scale green areas and water features should be designed to allow continuous and accessible engagement [59]. Green spaces that incorporate a variety of native plant species, rather than homogeneous vegetation, are known to enhance ecological sustainability and psychological benefits [51]. Similarly, water elements—such as streams or fountains—should offer dynamic multisensory stimulation, which can contribute to emotional calmness and mental restoration [60].

For indirect experiences of nature, design strategies must consider the age-related decline in sensory perception. Appropriate color and lighting design are critical for ensuring visibility and comfort. Brightness contrast improves legibility, while indirect lighting helps to prevent glare and visual fatigue [44]. Care should be taken with overly complex fractal patterns, which may overstimulate or exhaust aging visual systems [61].

For spatial and place-based experiences, design elements such as elevation changes or transparent structures should be carefully controlled, as they can evoke anxiety or impede movement among older residents [51]. While the combined presence of prospect and refuge is known to support environmental comfort [62], how this balance can be effectively achieved in residential settings for seniors remains underexplored. In practice, features such as rooftop gardens and shared community gardens in public senior housing have proven to strengthen social connectedness and foster residential attachment [44,63].

Taken together, these empirical insights emphasize the role of sensory and cognitive dimensions in shaping design outcomes for older adults. Building on these prior studies, this research incorporates sensory- and cognition-oriented design principles as core components of its biophilic strategy. In particular, the derivation of BRD factors and the development of the survey instrument were guided by evidence demonstrating the physiological and psychological relevance of sensory engagement and cognitive clarity in aging populations. These findings provide a valuable foundation for advancing future discussions on integrated biophilic design strategies tailored to senior residential environments.

3. Methodology

3.1. Survey Procedure and Participants

The survey was conducted from December 2024 to February 2025, targeting seniors residing in South Korea, including members of the baby boomer generation (born between 1955 and 1974). As the largest generational cohort in the country, Korean baby boomers are anticipated to exert substantial socio-environmental impacts as they transition into older adulthood. Participants were recruited through public announcements posted on local community bulletin boards, and selection was voluntary and randomized. The survey was administered remotely using an online platform to ensure accessibility. Of the 425 responses collected, 424 were deemed valid after excluding one case due to low response integrity. Detailed demographic information of the respondents is presented in

Table 2. Descriptive statistics of demographic information.

Demographic Information		Frequency (n)	%
Gender	Male	212	50.0
	Female	212	50.0
Age (years)	50–55	91	21.5
	56–60	86	20.3
	61–65	63	14.9
	66–70	123	29.0
	71 and above	61	14.4
Housing type	Apartment	299	70.5
	Townhouse	69	16.3
	Detached house	51	12.0
	One-room unit	5	1.1
Residential floor area (m2)	Less than 33	8	1.9
	33–66	44	10.4
	69–99	127	30.1
	102–132	172	40.6
	More than 133	73	17.2

.

The sample demonstrated a balanced gender distribution, with males and females each accounting for 50.0% of respondents. The largest age group was those aged 66 to 70, accounting for 29.0% of the sample, followed by the 50–55 (21.5%) and 56–60 (20.3%) age groups, which were also well represented. In terms of housing characteristics, the majority of participants (70.5%) reported living in apartment buildings, while the most common residential floor area was between 102 and 132 square meters (40.6%). These characteristics suggest that the sample largely reflects urban-dwelling seniors who maintain a relatively high degree of independence and economic stability.

3.2. Measurements

This study developed a structured survey instrument to assess HRQoL and preferences for BRD. The development process is summarized in Figure 3. The HRQoL section was constructed based on previous studies targeting Korean seniors and included 10 specific evaluation items. The BRD section was informed by the existing literature on senior-friendly housing and biophilic design, and items were categorized into three domains: direct experience of nature, indirect experience of nature, and experience of space and place. To ensure the validity of the instrument, the initial questionnaire was reviewed by five experts with over five years of experience in architectural design or environmental psychology.

A pilot test was then conducted with 30 seniors under the same conditions as the main survey, with one additional open-ended item included to gather feedback on the clarity and usability of the questionnaire. Based on this feedback, several revisions were made, such as rewording difficult terms (e.g., “biomimicry”) and adjusting font size and line spacing to improve readability. Reliability analysis of the pilot data confirmed that the instrument achieved acceptable levels of item communality and internal consistency.

The finalized survey instrument consisted of 10 items measuring HRQoL and 28 items assessing preferences for BRD. All items were rated on a 5-point Likert scale, with higher scores indicating better perceived quality of life and stronger preference for specific design elements. Reliability analysis demonstrated high internal consistency, with Cronbach’s alpha (α) values of 0.876 for the HRQoL items and 0.894 for the BRD preference items, suggesting strong measurement reliability (

Table 3. Overview of the survey instrument and internal reliability.

Survey Construct		Number of Items	Likert Scale	Cronbach’s α
HRQoL self-assessment		10	1 = Strongly agree, 5 = Strongly disagree	0.876
BRD preferences	Direct experience of nature	10	1 = Not at all preferred, 5 = Strongly preferred	0.894
	Indirect experience of nature	9
	Experience of space and place	9

). Detailed descriptions of the individual survey items are provided in

Table 4. Descriptive statistics for all study variables.

Survey Construct		Items	Item Description	M	SD
HRQoL self-assessment	Functional mobility	HQ1	I sometimes struggle to stand up, sit down, or climb stairs.	3.25	1.04
	Ability to perform daily activities	HQ2	I experience difficulties in personal tasks such as work, housework, or academic activities.	3.78	0.92
	Pain and discomfort	HQ3	I feel physical pain, discomfort, or heartburn.	3.60	1.05
	Sensory function	HQ4	I feel discomfort due to dull senses, impaired vision, or reduced hearing.	3.32	1.02
	Anxiety and depression	HQ5	I have been feeling depressed or anxious lately, and sometimes feel a tightness in my chest.	3.46	1.04
	Quality of sleep	HQ6	I often become sensitive, feel fatigued, or have difficulty sleeping.	3.43	0.96
	Cognitive function and memory	HQ7	I struggle to recall familiar words, recognize objects, or identify people.	3.25	1.00
	Hobbies and leisure activities	HQ8	I feel fearful or hesitant about engaging in hobbies, leisure activities, or travel, and often avoid such activities.	3.68	0.96
	Social relationships	HQ9	I feel physically or emotionally distant from my peers, family, or friends.	3.70	0.92
	Productive activities	HQ10	I feel dissatisfied with my level of productive activities or economic situation.	3.11	1.07
BRD preferences	Direct experience of nature	BRD1	Lightwell or courtyard	3.89	0.85
		BRD2	Varied angles and patterns of openings for daylight diffusion	3.68	0.91
		BRD3	Architectural openings and spatial structures facilitating natural ventilation	3.85	0.84
		BRD4	Water features and ornaments (waterways, fountains, wall fountains, cascading water decorations, etc.)	4.13	0.73
		BRD5	Skylights or atriums to see the sky	3.65	0.92
		BRD6	Large windows providing views of natural environments (trees, sea, mountains, etc.)	4.10	0.79
		BRD7	Indoor and outdoor gardens or plant decorations	3.91	0.82
		BRD8	Green walls or vertical gardens	3.75	0.96
		BRD9	Habitat environments for native species (aquariums, ponds, rooftop gardens, etc.)	3.28	0.95
		BRD10	Air-purifying vegetation and shading greenery	3.54	0.95
	Indirect experience of nature	BRD11	Realistic or metaphorical depictions of nature (paintings, photographs, videos, etc.)	3.43	0.87
		BRD12	Murals or decorations depicting nature	3.42	0.83
		BRD13	Finishes using natural or recycled materials (stone walls, architectural and interior finishes, handles, etc.)	3.60	0.94
		BRD14	Color schemes and palette planning based on natural landscapes	3.91	0.72
		BRD15	Architectural elements utilizing organic forms (columns, supports, walls, facades, etc.)	3.43	0.95
		BRD16	Ventilation openings and air circulation devices	3.96	0.76
		BRD17	Indirect and diffused lighting	3.97	0.74
		BRD18	Artificial natural lighting and warm-tone lighting	3.93	1.06
		BRD19	Architectural structures or designs mimicking the evolved morphological characteristics of natural organisms	3.24	0.91
	Experience of space and place	BRD20	Visually open small-scale resting spaces	4.19	0.72
		BRD21	Pavilions, shelters, or seating designs that provide a sense of protection	3.75	0.91
		BRD22	Balconies, decks, or curtain walls	3.77	0.88
		BRD23	Harmonized application of natural materials, textures, and patterns	3.36	0.97
		BRD24	Wayfinding information utilizing natural elements and features	3.65	0.87
		BRD25	Eco-friendly circulation paths (permeable pavements, parklets, etc.)	3.81	0.83
		BRD26	Community gardens and edible landscaping	3.70	0.91
		BRD27	Architectural elements reflecting local or regional characteristics (landscape colors, building heights, etc.)	3.60	0.90
		BRD28	Informational signage on biophilic applications and effects	3.47	0.91

Notes: M = Mean, SD = Standard deviation.

.

3.3. Data Analysis

In total, 424 valid survey responses were analyzed using IBM SPSS Statistics version 29.0.2.0. The data analysis procedure involved the following steps:

(1)

Descriptive statistics were first computed for all variables to assess the overall distribution of HRQoL levels and BRD preferences among senior participants;

(2)

A principal component analysis (PCA) with Varimax rotation was conducted on the HRQoL items to identify the underlying factor structure. Factors were extracted based on eigenvalues greater than 1.0, with a minimum factor loading threshold of 0.5;

(3)

Using the factor scores derived from the PCA, a two-step cluster analysis was performed. An initial hierarchical clustering approach was applied to determine the optimal number of clusters, followed by K-means clustering to clearly segment HRQoL profiles. Each cluster was then labeled based on the dominant characteristics of its factor composition;

(4)

Finally, a one-way ANOVA was conducted to examine differences in BRD preferences across the HRQoL-based clusters. All statistical tests were performed with a 95% confidence level, and the significance threshold was set at α = 0.05.

4. Results

4.1. Descriptive Statistics

Based on the descriptive statistics presented in Table 4, most HRQoL items had mean scores ranging between 3.2 and 3.7. In particular, HQ2 (ability to perform daily activities) and HQ9 (social relationships) recorded mean values exceeded 3.7, indicating that many seniors perceive their quality of life positively regarding maintaining everyday functionality and social connectedness. In contrast, lower scores were observed for HQ10 (productive activities), HQ7 (cognitive function and memory), HQ1 (functional mobility), and HQ4 (sensory function). These findings suggest a potential decline in cognitive and physical abilities, which may result in reduced engagement in productive roles and a diminished sense of economic satisfaction among seniors. These findings highlight the need for a comprehensive approach to enhancing seniors’ quality of life—one that goes beyond medical care or environmental adjustments. Effective strategies should integrate opportunities for meaningful engagement, cognitive stimulation, sensory support, and promotion of physical vitality.

Overall, seniors demonstrated moderate to high levels of preference across all BRD items. Many items scored above 3.8 points, indicating a clear expectation for and strong interest in nature-integrated residential environments. The five most highly rated elements—BRD20, BRD4, BRD6, BRD17, and BRD16—reflect seniors’ prioritization of sensory comfort, emotional stability, and visual access to nature [64,65]. These preferences highlight the importance of considering both the functional effectiveness and emotional connection of biophilic elements in senior housing environments. Conversely, lower preference scores—below a mean of 3.4—were observed for BRD19, BRD9, BRD23, and BRD12. These elements, which tend to be more abstract, symbolic, or require greater maintenance, may be perceived as less relevant or usable by individuals with diminished cognitive or sensory capacity. Such findings indicate that seniors tend to prefer biophilic design features that are more intuitive, tangible, and experientially grounded. This underscores the need for biophilic strategies to be carefully calibrated to align with the functional and perceptual capacities of seniors.

4.2. Factor Structure of HRQoL

According to the results of the factor analysis (

Table 5. Results of factor analysis.

HRQoL Factor M ± SD		Items		Factor Loadings	Eigenvalues	Dispersion Ratio (%)	Cronbach’s α
1	Social-economic QoL: 3.49 ± 0.78	HQ9	Social relationships	0.808	4.747	47.48	0.710
		HQ8	Hobbies and leisure activities	0.690
		HQ10	Productive activities	0.561
2	Mental-sensory QoL: 3.39 ± 0.79	HQ4	Sensory function	0.780	1.191	59.41	0.752
		HQ5	Anxiety and depression	0.689
		HQ7	Cognitive function and memory	0.594
3	Physical QoL: 3.5 ± 0.77	HQ3	Pain and discomfort	0.788	1.098	70.34	0.777
		HQ2	Ability to perform daily activities	0.646
		HQ6	Quality of sleep	0.625
		HQ1	Functional mobility	0.613

M = Mean, SD = Standard deviation.

), the Kaiser–Meyer–Olkin (KMO) measure was 0.902, indicating a high degree of sampling adequacy and strong correlations among variables. Bartlett’s test of sphericity was also significant (p < 0.00), confirming the suitability of the data for factor analysis. The extracted factors met established criteria, with all rotated component loadings exceeding 0.5 and eigenvalues greater than 1.0.

Three distinct HRQoL factors were identified: (1) Social-economic QoL, (2) Mental-sensory QoL, and (3) Physical QoL, in order of explained variance. These factors accounted for a cumulative variance of 70.3%, and each demonstrated acceptable internal consistency with Cronbach’s α values exceeding 0.70. The findings suggest that seniors’ quality of life is multidimensional, comprising interconnected domains of social engagement, emotional and cognitive stability, and physical functionality, which aligns with prior research [24]. The mental-sensory factor revealed a close relationship between sensory function and psychological/cognitive processes, highlighting the importance of integrating natural elements that foster both sensory stimulation and neurophysiological activation in senior living environments. Furthermore, the physical factor’s association with sleep quality underscores the need for spatial design strategies that support rest, recovery, and physical stability.

4.3. Identification of the HRQoL-Based Senior Cluster

Table 6. Senior health profiles identified by HRQoL factor-based cluster analysis.

Cluster		CL1	CL2	CL3	CL4	F
Name		Optimal Health Group	Physically Declining Group	Overall Low Health Group	Socially Vulnerable Group
N (%)		169 (39.8)	124 (29.2)	61 (14.4)	70 (16.5)
HRQoL factor M ± SD	Physical QoL	4.10 ± 0.71	2.92 ± 0.72	2.23 ± 0.74	3.26 ± 0.81	325.400 ***
	Mental-sensory QoL	4.23 ± 0.75	3.43 ± 0.74	2.41 ± 0.82	3.19 ± 0.92	242.906 ***
	Social-economic QoL	4.10 ± 0.74	3.54 ± 0.71	2.75 ± 0.89	2.60 ± 0.83	200.586 ***

M = Mean, SD = Standard deviation, *** p < 0.001.

summarizes the cluster analysis results, presenting the mean values of HRQoL factors across the identified groups. Four clusters were extracted, with statistically significant differences observed across all three HRQoL factors (p < 0.001).

The clusters represent four distinct HRQoL profiles among seniors. (1) Optimal Health Group—This group exhibited mean scores above 4.0 across all three HRQoL factors, indicating the most favorable overall health status. Members of this cluster demonstrated autonomy in daily life, emotional well-being, and strong social engagement, representing an ideal senior health profile. (2) Physically Declining Group—This group showed lower scores in physical QoL, while maintaining relatively stable levels of cognitive, emotional, and social functioning. Although physically limited, they continue to engage meaningfully in social and emotional domains. (3) Overall Low Health Group—Characterized by consistently low scores across all three factors, this group reflects the most vulnerable population, with diminished independence, limited social interaction, and psychological instability. This cluster highlights the need for comprehensive health support. (4) Socially Vulnerable Group—Despite relatively preserved physical health, individuals in this cluster scored low in the socio-economic domain. Their reduced life satisfaction appears to stem from weakened social ties and perceived role loss, rather than physical decline.

4.4. Analysis of BRD Preference Differences: ANOVA

Table 7. Group-wise preference scores for 28 BRD elements and corresponding statistical significance among HRQoL-based senior clusters.

Items	Optimal Health Group		Physically Declining Group		Overall Low Health Group		Socially Vulnerable Group		F	η2
	M	SD	M	SD	M	SD	M	SD
BRD1	3.91	0.89	3.77	0.77	4.02	0.85	3.93	0.87	1.302	-
BRD2	3.81	0.94	3.60	0.75	3.80	1.01	3.41	0.94	3.953 **	0.027
BRD3	3.85	0.94	3.91	0.75	3.89	0.9	3.73	0.71	0.437	-
BRD4	4.15	0.75	4.10	0.70	4.20	0.79	4.07	0.67	0.733	-
BRD5	3.69	0.96	3.57	0.80	3.79	1.07	3.54	0.88	1.175	-
BRD6	4.09	0.82	4.14	0.71	4.05	0.78	4.10	0.87	0.186	-
BRD7	3.89	0.85	3.90	0.82	4.13	0.72	3.80	0.83	2.347 *	0.016
BRD8	3.81	0.99	3.66	0.91	3.51	0.99	3.94	0.93	2.823 *	0.021
BRD9	3.64	0.98	3.65	0.75	3.70	0.88	3.59	0.91	0.197	-
BRD10	3.67	0.94	3.53	0.95	3.38	1.00	3.37	0.87	2.508	-
BRD11	3.47	0.91	3.51	0.77	3.41	0.99	3.23	0.82	1.741 *	0.012
BRD12	3.46	0.84	3.39	0.83	3.34	0.91	3.44	0.73	0.353	-
BRD13	3.70	0.94	3.63	0.84	3.51	0.99	3.39	1.04	2.616 *	0.018
BRD14	4.00	0.72	3.81	0.74	3.90	0.72	3.89	0.69	2.576 *	0.018
BRD15	3.51	0.96	3.48	0.88	3.20	1.14	3.37	0.80	1.887	-
BRD16	4.07	0.83	3.92	0.65	3.98	0.67	3.79	0.80	2.481 *	0.017
BRD17	4.02	0.79	3.98	0.66	3.89	0.73	3.93	0.73	0.590	-
BRD18	4.02	1.03	3.79	1.14	4.10	0.98	3.83	1.01	1.907	-
BRD19	3.34	0.95	3.23	0.84	3.18	0.87	3.07	0.92	2.623 *	0.018
BRD20	4.22	0.71	4.15	0.71	4.15	0.79	4.19	0.73	0.302	-
BRD21	3.86	0.86	3.72	0.93	3.70	0.99	3.61	0.91	1.414	-
BRD22	3.91	0.82	3.77	0.87	3.59	0.97	3.63	0.92	2.830 *	0.021
BRD23	3.46	0.99	3.34	0.86	3.15	1.09	3.34	0.98	1.628	-
BRD24	3.82	0.88	3.57	0.82	3.43	0.90	3.57	0.84	4.031 ***	0.028
BRD25	3.95	0.79	3.76	0.78	3.75	0.98	3.63	0.82	2.963 *	0.021
BRD26	3.80	0.94	3.65	0.83	3.70	0.95	3.53	0.91	1.622	-
BRD27	3.59	0.95	3.66	0.78	3.57	1.01	3.54	0.88	0.314	-
BRD28	3.59	0.95	3.44	0.76	3.26	1.11	3.39	0.84	2.327	-
Total	3.82	0.53	3.71	0.63	3.69	0.71	3.64	0.84	-	-

M = Mean, SD = Standard deviation, * p < 0.05, **p < 0.01, *** p < 0.001, - no data.

summarizes the group-wise mean scores and statistical results for all 28 BRD elements. To aid visual interpretation, Figure 4 highlights the average preference scores of the four senior clusters for the BRD elements that showed statistically significant differences. A total of 11 items showed statistically significant differences between groups (p < 0.05). These differences were most evident in elements related to sensory stability (e.g., BRD2: varied daylight angles), perceptual clarity (e.g., BRD24: nature-based wayfinding), and external connectivity (e.g., BRD22: balconies, BRD25: eco-friendly circulation paths). To aid practical interpretation beyond statistical significance, effect sizes (η²) were calculated for these elements using the ANOVA results. The η² values ranged from 0.012 to 0.028, suggesting small but meaningful differences in preference patterns. Though modest, the observed effects reflect consistent patterns that support the value of interpreting BRD preferences through the lens of differentiated health profiles.

Cluster-specific trends in BRD preferences are summarized as follows:

The Optimal Health Group demonstrated high preferences for most BRD elements, especially those promoting sensory comfort, openness, and social interaction. Their high functional capacity suggests they are well-suited for richly layered environments that support both autonomy and engagement, such as flexible open plans, multi-sensory stimuli, and diverse spatial programming.

The Physically Declining Group expressed strong preferences for restorative and low-exertion features, such as BRD14 (natural colors) and BRD16 (ventilation systems). These results imply that design for this group should prioritize low-stress environments, such as calming visual palettes, ergonomic pathways, and passive environmental controls, to reduce physical fatigue while supporting sensory regulation.

The Overall Low Health Group, despite reduced function across physical, emotional, and cognitive domains, preferred elements providing perceptual clarity and cognitive simplicity (e.g., BRD11, BRD24). This indicates a need for highly legible spaces that minimize cognitive load, incorporating consistent spatial cues, reduced visual clutter, and intuitive navigation to ensure comfort and autonomy.

The Socially Vulnerable Group had lower overall preferences but showed selective interest in elements supporting social connection via nature, such as framed outdoor views and communal gardens (e.g., BRD7, BRD22, BRD25). This highlights the importance of addressing emotional isolation by integrating shared green spaces, transparent circulation, and nature-mediated interaction zones.

5. Strategic BRD Framework

5.1. Summary of Residential Spatial Needs by Cluster

Based on the analysis of HRQoL profiles and BRD preference patterns, this section outlines the specific residential design needs of each cluster, considering their distinct physical, cognitive, and social characteristics (

Table 8. Design needs of the residential environment identified across HRQoL clusters.

Cluster	HRQoL Profile	Key Design Needs	Keywords
Optimal Health Group	High across physical, cognitive, and social dimensions	Open and flexible layouts allowing active engagement; multi-sensory stimulation; strong visual and physical connections with nature	Autonomy, diversity, openness
Physically Declining Group	Decline in physical functions, moderate in others	Short-distance movement; quiet, restorative green areas; sheltered and ventilated environments for comfort	Protection, recovery, safety
Overall Low Health Group	Overall low, particularly in cognitive and emotional functions	Clear zoning and orientation cues; sensory safety through material and color familiarity; simplified circulation	Cognitive clarity, sensory guidance
Socially Vulnerable Group	Low in social connection and emotional stability	Shared green spaces; nature-linked communal zones; visual openness toward outdoors to reduce isolation	Communication, external connection, visual openness

).

The Optimal Health Group favors open multi-sensory environments that promote active engagement with nature. The Physically Declining Group emphasizes safety, short walking distances, and spaces that support recovery. The Overall Low Health Group requires environments that minimize overstimulation and enhance cognitive clarity. Meanwhile, the Socially Vulnerable Group strongly prefers socially inclusive and visually accessible spaces that can alleviate feelings of isolation. Based on these differentiated requirements, the following sections organize BRD elements into functional categories that correspond to the design priorities of each HRQoL cluster.

5.2. Functional Typology of BRD Preference

To effectively translate preference patterns into design decisions, it is essential to understand how specific BRD elements function in relation to seniors’ HRQoL profiles. To this end, BRD elements that showed statistically significant differences in preference across clusters (p < 0.05) were reclassified into three functional categories:

(1)

Sensory-Based Physiological Stability

This category includes BRD elements that directly support physical comfort, environmental regulation, and sensory balance within the residential space. Features such as BRD2 (varied daylight patterns of daylight), BRD8 (green walls and vertical gardens), BRD16 (ventilation systems), and BRD13 (natural materials) help reduce physical fatigue, regulate circadian rhythms, and enhance sensory satisfaction. These attributes are important for seniors who are sensitive to thermal and visual comfort and spend extended periods indoors.

(2)

Cognitive Stimulation

These elements offer visual cues and symbolic references that aid in orientation, memory, and spatial recognition. BRD11 (natural imagery), BRD19 (biomimetic structures), and BRD24 (nature-based wayfinding) help establish perceptual coherence and cognitive clarity. Such features are especially beneficial for individuals experiencing cognitive decline or reduced emotional resilience.

(3)

External and Social Connectivity

This category encompasses design features that promote interaction, openness, and a sense of community. Elements such as BRD7 (indoor gardens and plant arrangements), BRD22 (balconies, decks, and curtain walls), and BRD25 (eco-friendly circulation paths) extend individual experiences toward shared engagement with nature. They help facilitate social participation and reduce isolation by enabling nature-mediated encounters beyond the individual scale.

A radar chart (Figure 5) was developed to visually summarize the functional categories and relative preferences across the four HRQoL clusters. This chart displays the mean scores of each group for 11 BRD elements, organized according to their functional classification. The visualization not only simplifies the interpretation of BRD preference data but also supports designers in prioritizing biophilic features based on the health-related design needs of diverse senior groups. By highlighting how each cluster aligns with specific biophilic functions, the radar chart provides a foundation for the strategic design matrix presented in the following section.

5.3. Strategic Recommendations for Cluster-Based BRD

This section proposes design strategies tailored to each HRQoL-based senior cluster. The goal is to bridge health-related limitations and the potential of biophilic design by selecting appropriate BRD elements for each cluster’s unique HRQoL characteristics and mapping them to user-specific spatial profiles. Figure 6 visualizes the multi-layered mapping structure between HRQoL profiles, spatial needs, functional demands, and corresponding BRD elements to illustrate the transition from user profiling to implementable strategies.

Each cluster’s HRQoL profile is associated with specific spatial requirements, and the application of BRD elements should be strategically adapted to reflect the dominant functional needs observed in each group.

Table 9. HRQoL cluster-based strategic BRD matrix.

HRQoL-Based Cluster	Profile Summary	* Key BRD Elements	Design Strategies	Example Application Spaces
Optimal Health Group	High quality of life across physical, mental, and social domains Strong autonomy and sensory receptivity	BRD2, BRD8, BRD13, BRD14, BRD16 BRD25, BRD22	Nature-centered spaces supporting multi-sensory engagement Integration of daylight, ventilation, and material/color variation Open structures that visually and physically connect to the outdoors	Living rooms, balconies, home offices, flexible open-plan spaces
Physically Declining Group	Marked decline in physical function Preference for protective, recovery-oriented environments	BRD7, BRD10, BRD8, BRD14, BRD16 BRD25	Restorative spaces emphasizing static nature experiences Garden-centered layouts with clear visual orientation Short and safe circulation paths with protective qualities	Indoor courtyards, indoor gardens, bench seating, corridors
Overall Low Health Group	Low physical, cognitive, and emotional function Emphasis on cognitive stability and sensory familiarity	BRD2, BRD13, BRD14, BRD16 BRD11, BRD24	Design centered on visual clarity, contrasting colors, and directional cues Minimized environmental complexity Use of wayfinding systems and immersive nature references	Bedrooms, entryways, corridors, personal rest areas, communal zones

* Key BRD elements that were both statistically significant in the ANOVA results and showed rel-atively higher mean values or distinctive preference trends within a given cluster.

summarizes the key design strategies identified for each cluster. The proposed strategies are grounded in BRD elements that showed statistically significant and distinct preference patterns within each group, and are aimed at supporting health-responsive and function-oriented spatial planning.

(1)

Optimal Health Group

Seniors in this cluster exhibit high levels of HRQoL, marked by autonomy, strong sensory receptivity, and a desire for interaction with natural elements. They prefer open flexible environments that provide multisensory stimulation and continuous indoor–outdoor connections. Key BRD elements include BRD2 (varied daylight patterns) and BRD14 (natural colors) for sensory-based physiological comfort, as well as BRD22 (balconies, decks, curtain walls) and BRD25 (eco-friendly circulation paths) for external connectivity. The recommended strategies involve open-plan living areas, open and extended balconies, and ecologically integrated circulation routes that support both physical activity and everyday encounters with nature.

(2)

Physically Declining Group

This group is defined by physical fatigue and reduced mobility, with a greater need for restorative and protective environments. Key design priorities include shortened walking distances, secure resting areas, and effective air circulation. Preferred BRD elements—such as BRD8 (green walls and vertical gardens), BRD14 (natural colors), and BRD16 (ventilation systems)—primarily support sensory comfort and recovery. Suitable strategies include enclosed courtyards, visually linked indoor planting areas, and circulation paths with a clear visual direction, promoting restorative static nature experiences.

(3)

Overall Low Health Group

Characterized by cognitive and emotional vulnerability, this cluster requires environments that offer clarity, predictability, and familiar sensory experiences. BRD elements such as BRD11 (natural imagery) and BRD24 (nature-based wayfinding) provide cognitive cues, while BRD13 (natural materials) enhances sensory stability. Design strategies should focus on high-contrast colors and textures, simplified layouts, and the inclusion of immersive natural representations, such as murals or vertical greenery, particularly along entrances and circulation zones. Special consideration should be given to entrance areas and circulation paths within housing complexes. These features can reduce confusion and support emotional regulation.

(4)

Socially Vulnerable Group

This cluster experiences pronounced social isolation and emotional disconnection and, therefore, values environments that facilitate emotional openness and nature-mediated interaction. Key BRD elements include BRD7 (indoor gardens and plant arrangements), BRD22 (balconies, decks, and curtain walls), and BRD25 (eco-friendly circulation paths), all associated with social and external connectivity. These features function as semi-public interfaces that soften the boundary between private and communal space, encouraging passive visual contact, spontaneous encounters, and a subtle sense of presence among others. Recommended strategies involve shared gardens, green-linked corridors, and semi-open balconies that support passive socialization and emotional relief. These strategies are particularly effective when integrated into everyday circulation paths and community spaces where incidental encounters naturally occur, helping rebuild social connection without requiring active participation.

This framework clearly demonstrates how the same biophilic elements can serve distinct strategic roles depending on residents’ HRQoL profiles. It underscores the value of a tailored health-responsive approach to residential design—one that supports seniors’ functional needs and emotional well-being, rather than relying on a universal model.

6. Conclusions

6.1. Summary of the Study

This study identified user clusters based on seniors’ HRQoL profiles and systematically linked their residential spatial needs to BRD elements, resulting in function-oriented design strategies. The conclusions aligned with the RQs are as follows:

(1)

Regarding RQ1, statistically significant differences were identified in 11 BRD elements across clusters, indicating that seniors’ spatial expectations and receptivity to design features vary meaningfully depending on their health status;

(2)

For RQ2, BRD elements were reclassified into three functional categories—sensory stability, cognitive stimulation, and social connection—and mapped onto the specific spatial needs of each cluster. This mapping demonstrated the feasibility of translating health characteristics into design logic;

(3)

In addressing RQ3, a strategic design matrix was developed, integrating HRQoL profiles, spatial demands, and BRD functionality. This matrix offers a structured health-responsive model that supports user-centered residential planning based on differentiated needs.

Overall, this framework provides both conceptual clarity and practical guidance for answering the critical question: “For which seniors, under what health conditions, should design be prioritized around which functions?” By articulating the link between health profiles and spatial strategies, the study contributes a scalable and evidence-informed approach to adaptive residential design that supports both academic exploration and real-world implementation.

6.2. Contributions and Implications

Compared to conventional senior housing design approaches, such as universal design frameworks or aging-in-place models, this study offers a more differentiated and health-responsive strategy. While traditional models often treat older adults as a homogeneous group with generalized needs, our framework incorporates HRQoL-based user profiling to reflect functional diversity and health-specific requirements. By aligning biophilic design elements with distinct senior clusters, the framework moves beyond static typologies and provides a scalable matrix for adaptive evidence-based planning. This not only addresses limitations in current health-insensitive design models but also enhances the practical relevance of biophilic strategies in real-world residential environments.

The primary contributions and implications of this study are as follows:

• It presents the feasibility of HRQoL-based user profiling for senior-centered residential planning;
• It enhances the applicability of BRD elements by reorganizing them into functional categories tailored to the needs of HRQoL clusters;
• It establishes a strategic foundation for policy-driven design guidelines through differentiated spatial strategies for each user cluster.

Rather than treating seniors as a uniform population, this study approaches them as diverse users with multidimensional health profiles and varying degrees of sensory and emotional receptivity. By integrating biophilic features that correspond to each cluster’s spatial and functional needs, the framework offers a planning tool relevant to both practitioners and policymakers. In particular, the mapping of BRD functions to HRQoL clusters can support responsive design strategies across a variety of settings, including senior housing, community centers, aging-in-place renovations, and public housing developments. The strategic matrix developed in this study can serve not only as a communication bridge between designers and policy stakeholders but also be translated into design checklists prioritized by user profiles.

In addition to its practical contributions, the framework also prompts ethical reflection on how design interventions for vulnerable seniors should be approached. Designing for health-compromised or socially isolated populations requires careful consideration to avoid reinforcing dependency, diminishing autonomy, or unintentionally stigmatizing users. Future applications of this framework should aim to balance safety and empowerment through inclusive, participatory planning processes that respect the lived experiences and preferences of older adults.

6.3. Limitations and Future Research Directions

While this study offers a novel HRQoL-based approach to biophilic residential design for older adults, several limitations should be acknowledged.

First, the study relied on survey-based responses, which reflect stated preferences rather than lived experiences. While useful for identifying general trends, self-reported data may be limited by cognitive bias or social desirability. Future studies could enhance validity by adopting mixed-methods approaches, such as combining self-reports with observational data and physiological measurements.

Second, conducting the survey online may have excluded seniors with low digital literacy or limited access to technology, potentially skewing the respondent pool. To improve inclusivity and representation, future research should consider offering multiple modes of participation, such as in-person interviews or paper-based surveys.

Third, although this study provides valuable typologies of senior clusters and associated design responses, it has limitations in capturing the dynamic and embodied nature of user experience. Follow-up research could employ immersive virtual environments or in situ prototyping to examine the real-time impact of specific BRD elements.

Finally, while the proposed framework demonstrates feasibility in aligning BRD elements with differentiated health profiles, its broader implementation may face challenges related to scalability, cultural adaptability, and institutional support. Translating cluster-specific strategies into real-world practice requires consideration of policy structures, economic feasibility, and regional planning variability. Moreover, biophilic preferences may not be universally applicable, as individual environmental sensitivities and cultural values can shape user responses in divergent ways. Future research should therefore examine not only the effectiveness of BRD interventions but also their acceptability, inclusivity, and equity across diverse populations and settings.

Despite these limitations, this study lays a foundational basis for advancing the empirical understanding and practical application of biophilic design tailored to aging populations.

Beyond addressing the limitations of the present study, the findings open several expanded avenues for future research. Experimental and observational studies could test how different configurations of BRD elements influence social interaction, cognitive performance, or physiological recovery in aging populations. Incorporating physiological measurements (e.g., heart rate variability, skin conductance level, or electroencephalography) may further clarify the links between specific biophilic stimuli and neurocognitive responses such as attention restoration or emotional regulation. Additionally, cross-cultural studies can explore how cultural values and environmental familiarity shape BRD preferences, supporting the development of more inclusive and context-sensitive design strategies. Simulation-based platforms may also be employed to develop participatory tools that allow older adults to visualize, modify, and evaluate BRD-integrated environments in real time. Collectively, these directions not only extend the current framework but also broaden its relevance across clinical, technological, and user-centered domains.