CommHEAT is a prototype mobile app developed by Iowa State University researchers to predict indoor temperatures and warn residents—particularly those without air conditioning—when conditions become dangerous. Built on nearly a decade of neighborhood data, sensor measurements and 3D thermal modeling, the app provides 12-hour forecasts, alerts, and a directory of nearby cooling centers. Pilot testing in Des Moines showed increased awareness and behavior change; researchers plan further analysis and new funding to expand features and public availability.
CommHEAT: Iowa State’s App That Predicts Dangerous Indoor Heat for Homes Without AC
CommHEAT is a prototype mobile app developed by Iowa State University researchers to predict indoor temperatures and warn residents—particularly those without air conditioning—when conditions become dangerous. Built on nearly a decade of neighborhood data, sensor measurements and 3D thermal modeling, the app provides 12-hour forecasts, alerts, and a directory of nearby cooling centers. Pilot testing in Des Moines showed increased awareness and behavior change; researchers plan further analysis and new funding to expand features and public availability.
08:10, 04.11.2025Health
ISU researchers build CommHEAT to forecast and warn of hazardous indoor heat
A multidisciplinary team at Iowa State University has developed CommHEAT, a prototype mobile app that estimates indoor temperatures, warns residents when conditions become dangerous, and points users to nearby cooling resources or support networks. The tool was built on nearly a decade of neighborhood and building data and was piloted with Des Moines residents during a recent summer heat season.
From neighborhood data to a public-health tool
Ulrike Passe, ISU architecture professor and director of the Center for Building Energy Research, led the three-year project, which received $1.2 million in funding from the National Science Foundation. The app grew out of earlier ISU work — including a seed initiative called "Big Data for Sustainable City Decision-Making" that received more than $400,000 — in partnership with the City of Des Moines to catalog tree canopy, building materials, lot layouts and how people interact with the built environment.
Why this matters
In 2017 the Polk County Health Department raised concerns about dangerously hot indoor conditions in some inner-city homes, many of which lack central air conditioning. Passe noted that in certain Des Moines neighborhoods, more than half of homes do not have central AC. Without a fixed indoor thermostat, building materials and contents warm at different rates influenced by factors such as nearby trees, parking lots and surface materials.
Data, sensors and modeling
Polk County distributed sensors to participating homes and shared those measurements with the ISU team. Researchers uploaded sensor data to a server hosted by ISU’s Virtual Reality Applications Center. Using that information, students and faculty created 3D models of houses, simulated outdoor conditions and ran thermal simulations to determine how sunlight, materials and neighborhood characteristics affect interior temperatures. Some modeled homes reached interior temperatures above 90°F under summertime conditions.
Predicting indoor heat and turning it into action
Combining sensor measurements, building models, neighborhood data and weather inputs allowed the team to predict indoor temperature "with some degree of accuracy," according to ISU professor Michael Dorneich. That capability motivated the creation of CommHEAT as a vehicle to deliver actionable information to residents.
The CommHEAT prototype displays outdoor conditions, an estimated indoor temperature, and a 12-hour forecast. It provides alerts when indoor heat reaches dangerous levels, a directory of nearby cooling centers, and a community page where users can invite trusted contacts to view home temperatures during emergencies.
Pilot testing and early feedback
Des Moines residents tested several iterations of CommHEAT over the summer. The research team sent short surveys to participants during heat events — defined for the study as at least three consecutive days with heat indexes exceeding 100°F — to capture habits, perceptions and comfort. Doctoral student Tian Yao is conducting follow-up interviews and said early feedback has been encouraging: participants reported increased awareness of heat risk and behavior changes such as taking breaks from work, wearing lighter clothing and using cooling packs.
"People feel that somehow it changed their behavior, or at least increased their awareness of the danger of the heat," said Tian Yao.
Limitations and next steps
During the pilot the app’s community network feature was limited because only homes without air conditioning were eligible to install the prototype; many users’ supporters have AC and thus could not join. Passe said she hopes to add notification features, broaden access, and continue refining predictions and user experience.
Passe cautioned that while installing air conditioning for everyone may seem like a simple fix, it carries significant financial and environmental costs. Instead, CommHEAT aims to provide a lower-cost, scalable tool for raising awareness, informing individual behavior, and guiding targeted interventions by cities and health agencies.
Looking ahead, the team plans to complete the NSF-required analyses and seek additional funding to move CommHEAT from prototype to a public app. "I want everybody who doesn’t have an air conditioner to have that app on their phone," Passe said.