The goal of this stepped wedge trial is to assess the practical effects of air conditioners on hot weather impacts among older adults. The main questions it aims to answer are:
How does the presence of an air conditioning unit affect heat stress, heat strain, mental health, and healthcare utilization among older adults who did not previously have access to air conditioning?
How, and in what conditioners, do older adults use air conditioning once it is installed in their home?
Researchers will compare participants in arms with (A) and without (B) air conditioning units in the first summer season; this will allow them to assess the effect of air conditioners. In the second summer season, both arms will have air conditioning units, but those in the year two distribution arm (B) will receive an electricity subsidy, while those in the year one AC distribution arm (A) will not, allowing researchers to assess the effect of an electricity subsidy.
Participants will be randomized to receive an air conditioner and financial support for electricity costs in either the first summer season or the second summer season of the study.
* Heat stress, heat strain, mental health, and healthcare utilization will be assessed via participant survey. * Air conditioner utilization will be assessed via continuous load monitoring devices. * Indoor air temperature will be assessed via continuous data loggers.
reside in Roxbury, Dorchester, East Boston or Mattapan MA
age 55-95 years old
speak English or Spanish
do not have air conditioning in the home
None
Parallel
Air Conditioner
Other interventionAir conditioners will be window-mounted units powered by 110v AC.
Electricity subsidy
Other interventionElectricity subsidies will consist of a single block subsidy of USD 100, intended to provide support for the electricity costs associated with operating an air conditioning unit.
Environmental Symptoms Questionnaire (ESQ-IV)
The primary outcome will be a two-sample t-test for differences in means in the treatment and control groups in responses to the Environmental Symptoms Questionnaire (ESQ-IV). We will assess self-reported health impacts across all sites using a modified (truncated) version of the Environmental Symptoms Questionnaire (ESQ-IV), referred to as the Heat Stress Symptoms Questionnaire. Originally developed for assessing the health impacts of environmental exposures (Sampson et al, 1993), the ESQ-IV has been validated for assessing health impacts associated with heat illness in soldiers (Johnson \& Merullo, 1993). More recently, smaller subsets of the ESQ-IV's questions have served as a health endpoint for assessing the impacts of heat stress and acclimatization in the general population and older adults (McGarr et al, 2023; Manning et al, 2023). In an urban population, a question using similar language in a simplified format was used to assess prior experiences of heat-related illness (Card
Air Conditioner Utilization
Air conditioner utilization will be prospectively assessed throughout the study. In year 1, air conditioner utilization will be analyzed in relation to indoor air temperature to identify threshold temperatures that trigger AC utilization. In Year 2, utilization rates and thresholds will be compared between the the two arms to assess the impact of electricity subsidies on AC utilization.
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Harvard School of Public Health (HSPH)
Lead sponsor
Fogarty International Center of the National Institute of Health
Collaborator
