Hot Weather; Adverse EffectNCT06982339
Beat the Heat Boston
A study testing Air Conditioner and Electricity subsidy in people with Hot Weather; Adverse Effect and Heat Effect, run by Harvard School of Public Health (HSPH) at 1 site in United States.
Trial 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… Read more about this study
- Who is it for?
- Ages 55 to 95 years
- Conditions the study is for
- Hot Weather; Adverse Effect, Heat Effect, Heat Stress
- What is being tested?
- Air Conditioner and Electricity subsidy
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 100 participants
- Where
- 1 siteUnited States
- Study dates
- 19 May 2025to 15 Oct 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 55 to 95 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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
- living with at least one of the following conditions: chronic CVD (hypertension, hyperlipidemia, diabetes, history of stroke or myocardial infarction, atrial fibrillation, or heart failure), chronic pulmonary disease (asthma, COPD/emphysema, interstitial lung disease), chronic neurologic disease (stroke, Parkinson's disease, or other chronic neurologic conditions), chronic mental health conditions (including anxiety disorder, major depression, bipolar disorder), and/or history of hospitalization (defined as spending at least one night in the hospital) for any reason within the past three years.
Who cannot join
- Lack a location in their home suitable for installation of the AC unit provided during the research study.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Caleb Dresser Assistant Professor in Environmental Health, MD MPH contact
United States1 site, 1 recruiting
- Recruiting
Harvard TH Chan School of Public Health
Boston, Massachusetts, 02215
Caleb J Dresser, MD MPH, 6174950000, cdresser@hsph.harvard.edu
About this study
Official title: Beat the Heat: Impacts of Heat on Health in Boston and Strategies to Address Them
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?
Read more
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.
Read the 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
- Being tested
- Air Conditioner, Electricity subsidy
- Keywords
- Cooling, Air conditioner, Heat related illness, stepped wedge
- Medical subject headings
- Heat Stress Disorders, Heat Stroke, Heat Exhaustion
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Air ConditionerOther
Air conditioners will be window-mounted units powered by 110v AC.
Electricity subsidyOther
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.
| Study group | Role | What they receive |
|---|---|---|
| Early Air Conditioning | Experimental | Year 1: Participants receive a window AC unit and a financial subsidy for electricity.
Year 2: Participants continue to have their AC unit, but do not receive a financial subsidy for electricity. Receives: Other: Air Conditioner; Other: Electricity subsidy |
| Delayed Air Conditioning | No intervention | Year 1: No intervention. Year 2: Participants receive an AC unit along with a financial subsidy for electricity. |
What is being measured
The primary outcome is the main question the study is designed to answer.
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
Measured: Difference in self-reported symptoms on HSSQ administered in the late summer season, 2-12 weeks after enrollment.
Secondary outcomes (1)
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.
Measured: From enrollment to study completion, approximately 2 years.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 May 2025
- Study start19 May 2025
- Primary completion15 Oct 2026 (estimated)
- Study completion15 Oct 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Hot Weather; Adverse EffectStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- This study follows a stepped wedge randomized controlled trial (SW-RCT) design to evaluate the health and environmental impacts of air conditioning among older adults with chronic health conditions. A total of 100 participants are randomized into two groups: Arm A (Early AC Group): Receives a window AC unit in Year 1, along with a financial subsidy for electricity.. Arm B (Delayed AC Group): Receives an identical AC unit in Year 2, along with a financial subsidy for electricity. In Year 1, participants in Arm A (AC) are compared to those in Arm B (no AC) to assess the direct effect of AC access. In Year 2, both arms have AC units, but only Arm B receives the electricity subsidy, allowing evaluation of cost as a barrier to use.
- Masking
- None (open label)
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Harvard School of Public Health (HSPH)
- Sponsor type
- University, hospital or other
- Collaborators
- Fogarty International Center of the National Institute of Health
- Responsible party
- Principal investigator, Gary Adamkiewicz, Harvard School of Public Health (HSPH)
- Investigators
- Gary Adamkiewicz Associate Professor of Environmental Health and Exposure Disp., PhD, MPH, MS, Principal investigator, Harvard School of Public Health (HSPH)
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06982339
- Sponsor's protocol ID
- IRB25-0366
- Other IDs
- 1P20TW013028-01
- Status last verified
- Aug 2025
- First submitted
- 13 May 2025
- Last updated
- 22 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Non-identifiable study dataset, specifically data on treatment arm assignment and survey results including primary endpoint
Study at a glance
From the registry record, last updated by the sponsor on 22 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Beat the Heat: Impacts of Heat on Health in Boston and Strategies to Address Them
- ClinicalTrials.gov ID
- NCT06982339
- Acronym / sponsor ID
- IRB25-0366
- Conditions
- Hot Weather; Adverse Effect, Heat Effect, Heat Stress, Heat Stroke, Heat Exhaustion, Heat Exposure, Heat Strain
- Keywords
- Cooling, Air conditioner, Heat related illness, stepped wedge
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- Harvard School of Public Health (HSPH)University, hospital or other
- Collaborators
- Fogarty International Center of the National Institute of Health
- Study start
- 19 May 2025 (actual)
- Primary completion
- 15 Oct 2026 (estimated)
- Study completion
- 15 Oct 2026 (estimated)
- First posted
- 21 May 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- This study follows a stepped wedge randomized controlled trial (SW-RCT) design to evaluate the health and environmental impacts of air conditioning among older adults with chronic health conditions. A total of 100 participants are randomized into two groups: Arm A (Early AC Group): Receives a window AC unit in Year 1, along with a financial subsidy for electricity.. Arm B (Delayed AC Group): Receives an identical AC unit in Year 2, along with a financial subsidy for electricity. In Year 1, participants in Arm A (AC) are compared to those in Arm B (no AC) to assess the direct effect of AC access. In Year 2, both arms have AC units, but only Arm B receives the electricity subsidy, allowing evaluation of cost as a barrier to use.
| Arm | Type | Receives |
|---|---|---|
| Early Air Conditioning | Experimental | Other: Air Conditioner, Other: Electricity subsidyYear 1: Participants receive a window AC unit and a financial subsidy for electricity. Year 2: Participants continue to have their AC unit, but do not receive a financial subsidy for electricity. |
| Delayed Air Conditioning | No intervention | –Year 1: No intervention. Year 2: Participants receive an AC unit along with a financial subsidy for electricity. |
Who may qualify
- Ages
- 55 to 95 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- 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
- living with at least one of the following conditions: chronic CVD (hypertension, hyperlipidemia, diabetes, history of stroke or myocardial infarction, atrial fibrillation, or heart failure), chronic pulmonary disease (asthma, COPD/emphysema, interstitial lung disease), chronic neurologic disease (stroke, Parkinson's disease, or other chronic neurologic conditions), chronic mental health conditions (including anxiety disorder, major depression, bipolar disorder), and/or history of hospitalization (defined as spending at least one night in the hospital) for any reason within the past three years.
Key exclusion criteria (1 listed)
- Lack a location in their home suitable for installation of the AC unit provided during the research study.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Air ConditionerAir conditioners will be window-mounted units powered by 110v AC. | Other | Early Air Conditioning |
| Electricity subsidyElectricity 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. | Other | Early Air Conditioning |
Primary outcome
Environmental Symptoms Questionnaire (ESQ-IV)
Time frame: Difference in self-reported symptoms on HSSQ administered in the late summer season, 2-12 weeks after enrollment.
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
1 secondary outcome
Air Conditioner Utilization
Time frame: From enrollment to study completion, approximately 2 years.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 Jan 2026.
- Individual participant dataSharing planned: Yes. Non-identifiable study dataset, specifically data on treatment arm assignment and survey results including primary endpoint
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Caleb Dresser Assistant Professor in Environmental Health, MD MPH contact
Gary Adamkiewicz Associate Professor of Environmental Health and Exposure Disp., PhD, MPH, MS principal investigator
Harvard School of Public Health (HSPH)
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Air Conditioner and Electricity subsidy in people with Hot Weather; Adverse Effect and Heat Effect, run by Harvard School of Public Health (HSPH) at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 22 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Caleb Dresser Assistant Professor in Environmental Health, MD MPH ((617) 446-3248, beattheheatboston@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Environmental Symptoms Questionnaire (ESQ-IV) (time frame: Difference in self-reported symptoms on HSSQ administered in the late summer season, 2-12 weeks after enrollment.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 Jan 2026.