Aesthetics over health: stakeholder perceptions of residential window design, indoor ventilation, disease risk, and energy use in urban Dar es Salaam, Tanzania: a mixed-methods study.

BACKGROUND

Residential window design is a primary determinant of natural ventilation in urban housing; however, the factors driving window design choices in rapidly urbanizing sub-Saharan African cities remain poorly understood. In Dar es Salaam Tanzania, sliding aluminum windows have become increasingly dominant in the residential housing market, yet evidence on how stakeholder perceptions of these designs relate to indoor ventilation adequacy, disease risk, and household energy use remains scarce.

METHOD: This mixed-methods study was conducted in Dar es Salaam Tanzania, between July and October 2025. A structured questionnaire was administered to 611 participants (496 household respondents and 115 hardware store vendors), followed by two focus group discussions with housing stakeholders. Descriptive statistics (frequencies and proportions) summarized participant and household characteristics. Associations between window designs and self-reported diseases and use of artificial cooling systems were examined using chi-square tests and logistic regression, with statistical significance set at a p-value < 0.05. Focus group data were analyzed using thematic analysis, and a desktop review was done to assess the presence of multisectoral ventilation guidance.

RESULTS

Sliding aluminum windows dominated the market (57% of sales) and household installations (47%), driven primarily by aesthetic considerations (46%). Awareness of ventilation guidelines was low across all stakeholder groups (18%). Limited airflow was significantly associated with greater reliance on mechanical fans (χ2(1) = 5.72, p = 0.017). Large household size was the strongest predictor of both malaria (OR = 2.65, 95% CI: 1.61-4.39, p < 0.001) and respiratory infections (OR = 3.74, 95% CI: 1.17-12.0, p = 0.026). Use of gas as cooking fuel was protective against respiratory infections (OR = 0.35, 95% CI: 0.14-0.85, p = 0.021). The desktop review revealed no enforceable benchmarks linking window design to ventilation performance, disease prevention, or energy efficiency in Tanzanian building regulations.

CONCLUSION

Market dynamics and structural constraints shape window design choices in urban Dar es Salaam more than health-oriented performance standards. Bringing public health ideas into housing rules, creating better ventilation guidelines for specific areas, and raising community awareness could improve indoor air quality and reduce reliance on energy-intensive solutions in rapidly growing cities.