Mitigating indoor thermal stress and improving health: A case study of green and healthy housing for older adults in Phoenix, Arizona

Background.  Climate change is predicted to degrade indoor environmental quality associated with the thermal environment of buildings (Institute of Medicine 2011).  Mitigation of thermal stress inside homes is important to older low-income populations whose age, health, and economic circumstances make them vulnerable to extreme temperatures/fluctuations.  Design interventions in places already experiencing extreme temperature conditions provide opportunities to impact on occupants’ health and comfort, which informs how to best target interventions for the future. 

Case Study and Intervention.  This presentation describes a 2-year study in Phoenix examining how indoor temperatures, residents’ thermal assessments, and health conditions of low-income older adults were altered following a “green retrofit” that targeted energy efficiency. 

Methods.  This study was a one-group pre-test, post-test research design, collecting data of the same residents and apartment units once before the renovation and twice after its completion.  The study’s first panel included 77 residents from 74 units; 57 residents and 53 units remained by the third panel.  Data collection included:  temperature, recorded every 15 minutes for five days; and  (b) resident reported health conditions, perceptions and assessments of the environmental quality of their homes.  Fixed effects regression models were used in analyzing data.  

Results. Key findings include:

• Instances of temperatures exceeding ASHRAE recommended threshold of 81°F are significantly fewer one year after the retrofit, suggesting that renovations reduced and stabilized temperature extremes.
• Reductions in indoor temperatures over 81°F resulted in reports of improved quality of health/life, reduced emotional distress, and increased number of hours sleeping.