Evaluating the effectiveness of building retrofit strategies for reducing indoor overheating risks in elderly apartments

Excess indoor heat significantly impacts the health and well-being of occupants, particularly vulnerable populations such as the elderly. In Canada, efforts to mitigate greenhouse gas (GHG) emissions have spurred the development of more energy-efficient residential buildings. This includes constructing highly insulated and airtight homes, as well as retrofitting existing dwellings to reduce winter heating demands and associated GHG emissions. However, if retrofits are not properly executed, they can lead to increased risks of indoor air pollution, dampness, and summertime overheating. With Canada on track to become a super-aged country, older adults (those over 65) are increasingly encouraged to ‘age in place,’ thereby heightening their risk of indoor heat exposure. Coupled with the anticipated rise in the frequency and intensity of climatic heatwaves due to climate change, these factors underscore the urgency of addressing overheating in Canadian homes, particularly for the elderly.

The aim of this study is to evaluate the effectiveness of various retrofit strategies in reducing indoor overheating risks in elderly apartments without air conditioning. To achieve this, a simulation-based approach was employed. A calibrated building energy model was developed to assess the impact of different retrofit strategies on indoor temperature regulation.

Preliminary findings from the simulations indicate that the most effective measures for mitigating indoor overheating are the use of phase change materials (PCM) in building envelopes, increased natural ventilation, and the strategic use of ceiling fans. PCMs proved particularly beneficial in regulating indoor temperatures by absorbing and releasing thermal energy, thereby reducing peak temperatures during heatwaves. Enhanced natural ventilation facilitated the expulsion of warm indoor air and the introduction of cooler outdoor air, while ceiling fans improved air circulation and enhanced thermal comfort.

These findings are significant as they provide evidence-based recommendations for retrofitting elderly apartments to combat indoor overheating. Implementing these strategies can help protect the health and well-being of elderly residents, particularly during periods of extreme heat. Furthermore, these measures can contribute to broader GHG mitigation efforts by reducing the reliance on air conditioning, thereby lowering energy consumption and emissions. The study underscores the importance of carefully planned retrofits to ensure that energy efficiency measures do not inadvertently compromise indoor air quality and thermal comfort, particularly for vulnerable populations.