NCT06982339

Beat the Heat Boston

Beat the Heat: Impacts of Heat on Health in Boston and Strategies to Address Them

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 100 (estimated)
• Sponsor: Harvard School of Public Health (HSPH) · Academic / Other
• Sex: All
• Age: 55 Years – 95 Years
• Healthy volunteers: Not accepted

Summary

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.

Detailed description

This community-based, randomized stepped wedge trial investigates whether the provision of educational resources and air conditioning (AC) improves thermal comfort and health outcomes among older adults with chronic disease and material hardships. The study will enroll 100 participants residing in at risk neighborhoods. Eligibility criteria include adults aged 55-95 who speak English or Spanish, lack access to home cooling systems, and have at least one qualifying chronic health condition or a history of recent hospitalization (see Eligibility section) . Participants will be randomly assigned (1:1) to receive window AC units and an electricity cost subsidy either in Year 1 or Year 2. All participants in both arms will receive a baseline intervention including heat health educational materials and cooling kits. Data collection will occur over two warm seasons (April-September) and involve pre- and post-intervention assessments using structured surveys, real-time environmental monitoring, and AC usage tracking. Surveys administered at enrollment and in late summer each year will capture a broad range of covariates including sociodemographic data, housing conditions, health service utilization, self-reported symptoms, and adaptive behaviors. Heat stress, heat strain, mental health, and healthcare utilization outcomes will be assessed via surveys that include previously validated survey instruments. Specific emphasis will be placed on measures of energy insecurity, such as utility shutoff notices, receipt of energy assistance, and trade-offs between essential expenses. Environmental sensors will log indoor temperature, humidity, and pollutant data throughout the study period. The primary outcome is self-reported health status as measured by a modified ESQ-IV, supplemented by secondary metrics including ASHRAE thermal comfort scores, POMS, emergency department presentations, and hospitalizations. Statistical analysis will employ two-sample t-tests to detect treatment effects, with a minimum detectable effect size of 5.66 assuming a standard deviation of 10 and balanced sample sizes. This study aims to empirically quantify the health benefits of cooling interventions in high-risk older adults and inform scalable public health strategies that address the intersecting challenges of urban heat, chronic disease management, and housing-related inequities.

Conditions

• Hot Weather; Adverse Effect
• Heat Effect
• Heat Stress
• Heat Stroke, Heat Exhaustion
• Heat Exposure
• Heat Strain

Interventions

Type	Name	Description
OTHER	Air Conditioner	Air conditioners will be window-mounted units powered by 110v AC.
OTHER	Electricity subsidy	Electricity 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.

Timeline

• Start date: 2025-05-19
• Primary completion: 2026-10-15
• Completion: 2026-10-15
• First posted: 2025-05-21
• Last updated: 2026-01-22

Locations

1 site across 1 country: United States