Improving Indoor Environmental Quality in Existing Buildings through Sustainable Retrofitting

Indoor Environmental Quality (IEQ) in existing buildings has increasingly become a focal point within the broader discourse on sustainable development, given its critical implications for occupant health, comfort, and overall productivity. As existing buildings age and their performance deteriorates, it is imperative to explore sustainable retrofitting as a viable solution to enhance IEQ while promoting environmental sustainability. This study assessed the role of sustainable retrofitting in improving IEQ and identified retrofitting approaches that are environmentally sustainable and effective in enhancing indoor conditions. The study employed a quantitative methodology using simple random sampling technique. Ninety-eight (98) responses were gathered and analysed using descriptive statistics, one-sample t-test and the Principal Component Analysis (PCA). The study found that sustainable retrofitting contributes to thermal regulation, volatile organic compounds (VOC) reduction, smart ventilation provision, and enhanced cognitive wellbeing. Additionally, sustainable retrofitting was found to effectively stabilise indoor temperatures and boost occupant satisfaction, leading to improved indoor temperature regulation and increased comfort satisfaction across seasons. However, certain roles, such as radon mitigation through airtightness and enhancing circadian rhythm, were not statistically significant. The study further identified significant sustainable retrofitting strategies, such as the use of CO₂ and VOC sensors, the use of bio-based insulation, the use of low-VOC materials, and smart HVAC controls. From a policy and practical standpoint, the study supports the integration of sustainable retrofitting into national building codes, green certification frameworks, and climate resilience strategies. The study recommends the urgent need for tailored training and awareness programs for built environment professionals, especially in developing regions, to foster adoption of underutilised strategies such as renewable energy and dynamic environmental controls.