How Can I Prepare My Home for Extreme Summer Heat?
Preparing before an extended period of high heat can reduce strain on the cooling system, limit unnecessary heat entering the home and make it easier to respond if the air conditioner or electrical service fails. A useful plan should address cooling equipment, sunlight, air leakage, hydration, emergency supplies and the needs of people and pets who may be more vulnerable to heat.
What should you check before extreme heat arrives?
Test the air conditioner before the heat wave, inspect the accessible air filter and make sure supply registers and return grilles are not blocked. Confirm that the thermostat is operating normally and arrange service early if the system is not cooling, is leaking water or is making unusual sounds.
Close shades or curtains where strong sunlight enters, repair accessible weatherstripping gaps and reduce unnecessary indoor heat from ovens, lighting and electronics. Prepare drinking water, medications, phone chargers and a plan for reaching an air-conditioned location if the home loses cooling.
Do not rely only on a fan when indoor temperatures become dangerously high. Pay particular attention to children, older adults, people with health conditions and pets, and seek medical help promptly when signs of heat-related illness appear.
Start by identifying how extreme heat affects your home
Two homes in the same neighborhood can perform differently during a heat wave. Roof exposure, window direction, insulation, air leakage, cooling-system condition and shade all influence indoor temperatures.
Think about previous hot periods. Identify which rooms became uncomfortable first, whether the air conditioner ran continuously and whether indoor humidity increased even while the home remained reasonably cool.
Also identify household members who may need additional support, available air-conditioned locations and how transportation, medications and pets would be handled if the cooling system failed.
Upper-floor or west-facing rooms become much hotter in the afternoon.
The air conditioner runs for long periods without reaching the thermostat setting.
The home becomes uncomfortable quickly during a short power outage.
A household member or pet may be especially vulnerable to heat.
Use previous hot days as a property-specific guide. A short temperature log can show when the home begins falling behind and which rooms need attention first.
Prepare the cooling system before the hottest weather
Cooling equipment is more likely to reveal an existing problem when outdoor temperatures rise and the system operates for longer periods. Testing it early provides more time to arrange service.
Test cooling before the heat wave
Confirm that the thermostat calls for cooling, air moves from the vents and the indoor temperature begins to respond.
Inspect the accessible air filter
Replace or clean it according to the equipment instructions when it is visibly loaded or overdue.
Clear supply and return openings
Move furniture, rugs, curtains and stored items away from registers and return grilles.
Observe the outdoor unit safely
Keep loose vegetation and debris from crowding the exterior of the equipment without opening panels or touching wiring.
Look for visible ice or water
Check accessible equipment surfaces and nearby floors for frost, dripping or condensate overflow.
Review thermostat schedules
Confirm that away, vacation, utility or energy-saving settings will not unexpectedly raise the indoor temperature.
Arrange maintenance before peak demand
Professional service may be easier to schedule before the hottest days and can identify developing performance issues.
Keep equipment records accessible
Gather model information, service history, warranty details and the contact information for the usual HVAC provider.
Lowering the thermostat excessively does not cool most homes faster. A much lower setting may cause the system to run longer without changing its cooling rate.
Reduce heat entering through windows and direct sunlight
Sunlight passing through windows can add substantial heat, especially in rooms with large east-, south- or west-facing glass. The effect may be strongest during different parts of the day.
Close shades before direct sun reaches the room
Interior shades, curtains and blinds can reduce some solar heat entering the living space.
Use exterior shading where appropriate
Awnings, shutters and other exterior shading may intercept sunlight before it reaches the glass when properly designed and secured.
Check temporary coverings for safety
Do not block required emergency exits, ventilation openings or equipment clearances.
Identify the hottest window exposures
Afternoon overheating often corresponds with strong west-facing sunlight.
Check skylights and glass doors
Overhead and large glass areas may contribute more heat than smaller wall windows.
Consider longer-term window improvements carefully
Films, screens, shading and replacement windows should be selected for the glass type, climate and building conditions.
Close coverings before the room becomes hot. Preventing solar heat from building up is generally more effective than trying to remove it afterward.
Limit uncontrolled hot and humid air entering the home
Gaps in the building enclosure can allow hot outdoor air, humid crawlspace air or attic air into conditioned rooms. Air leakage can increase both temperature and moisture loads.
Check exterior-door weatherstripping
Damaged or missing seals may allow warm air into the home around the door edges.
Look for visible gaps around accessible windows
Loose frames, failed seals and deteriorated materials may contribute to drafts and moisture entry.
Check accessible attic hatches
An unsealed or poorly insulated hatch may allow attic heat into nearby rooms.
Keep garage-to-house doors closed
A hot garage can transfer heat and contaminants into adjoining areas when doors remain open or seals are damaged.
Check for open fireplace dampers where applicable
An open or poorly sealed fireplace path may affect indoor air movement when the fireplace is not in use.
Consider professional air-leakage testing
Building-performance testing can identify leakage paths that are not obvious through visual inspection.
Do not seal intentional vents or drainage openings. Combustion, attic, crawlspace, wall and appliance systems may contain openings with important functions.
Reduce unnecessary heat produced inside the home
Appliances, lighting, electronics, hot water and household activities can add heat that the cooling system must remove.
Limit oven use during the hottest hours
Use safer lower-heat preparation methods when practical and appropriate for the household.
Use kitchen exhaust appropriately
Exhaust cooking heat and moisture when the system is designed to vent outdoors.
Turn off unnecessary lighting
Some lighting and electrical equipment can add noticeable heat to smaller rooms.
Reduce electronics in closed rooms
Computers, gaming systems and other equipment can raise room temperature during long operating periods.
Schedule laundry thoughtfully
Dryers and hot-water use can add heat and moisture, particularly when exhaust or ventilation is inadequate.
Keep exterior doors closed
Repeated door opening can introduce additional hot and humid outdoor air.
Outdoor cooking equipment must stay outdoors. Never use grills, charcoal appliances, camp stoves or fuel-burning outdoor equipment inside a home, garage or enclosed area.
Prepare for a cooling or power outage
High electrical demand, storms and utility problems can interrupt cooling during extreme heat. A backup plan should be made before indoor temperatures begin rising.
Cooling destination
Identify a cooling center, public building, hotel or trusted person’s air-conditioned home that can be reached safely.
Transportation
Plan how household members and pets would travel if local transportation or vehicle access becomes limited.
Drinking water
Keep an appropriate supply of drinking water available, particularly when the home relies on an electrically powered private well.
Medications
Review medications that require refrigeration and health needs that may be affected by heat.
Communication
Charge phones, portable power banks and other necessary communication equipment.
Generator planning
Review outdoor placement, fuel, connection and carbon-monoxide requirements before an outage.
Refrigerated food
Know how the household will monitor food safety if refrigeration is interrupted.
Emergency contacts
Keep utility, medical, HVAC, property-management and local emergency contacts available.
Portable generators must remain outdoors. Never operate a generator in a home, garage, basement, crawlspace, shed or enclosed porch.
Plan for people and pets who may be vulnerable to heat
Heat can affect anyone, but some people may have greater difficulty regulating body temperature, recognizing symptoms or reaching a cooler location.
Older adults may need regular check-ins
Confirm that cooling is operating and that they have access to water, transportation and assistance.
Infants and children can overheat quickly
Caregivers should monitor the indoor environment and follow appropriate medical and public-health guidance.
Health conditions may increase risk
People with cardiovascular, respiratory and other medical conditions may need an individualized heat plan developed with a healthcare professional.
Some medications require special planning
Ask a pharmacist or healthcare professional about storage and heat-related concerns rather than changing medication use independently.
Pets need cool spaces and water
Provide fresh water and a safe indoor environment, and consult a veterinarian when heat exposure or symptoms are a concern.
Social isolation can increase danger
Establish a check-in plan for household members, neighbors and relatives who may not recognize or report worsening indoor conditions.
Never leave a person or pet in a parked vehicle. Vehicle interiors can become dangerously hot very quickly, even when windows are partly open.
What to monitor while extreme heat continues
Once the heat event begins, monitor indoor conditions rather than assuming that the thermostat setting reflects the temperature in every room.
- Monitor indoor temperature in representative rooms.
- Keep shades and curtains closed against strong direct sunlight.
- Use air conditioning or move to an air-conditioned location when the home cannot remain safely cool.
- Drink water regularly according to appropriate health guidance.
- Reduce strenuous outdoor activity during the hottest hours.
- Check on household members, neighbors and relatives who may need assistance.
- Avoid unnecessary oven, dryer and high-heat appliance use.
- Keep pets indoors in a safe environment with water.
- Follow local heat, air-quality and utility alerts.
- Leave for a cooler location before indoor conditions become dangerous.
Fans move air but do not lower the room temperature. They should not be treated as a substitute for air conditioning or a cooler location when indoor conditions become dangerous.
Warning signs that require immediate or prompt attention
Extreme heat can create both health emergencies and building-system hazards. Personal safety should take priority over keeping the home occupied.
Seek immediate help or move to safety when:
- A person becomes confused, loses consciousness or has other signs of a possible heat emergency.
- The home cannot maintain a safe indoor temperature.
- The air conditioner stops and a vulnerable occupant cannot be moved to a cooler location without assistance.
- Smoke, sparks, burning odors or electrical arcing appears.
- The cooling system repeatedly trips a breaker.
- Water reaches HVAC wiring, outlets or electrical equipment.
- A utility or emergency authority advises evacuation or relocation.
- A pet shows signs of severe heat distress.
- The indoor temperature rises steadily while the air conditioner runs.
- Airflow becomes noticeably weaker.
- The system starts and stops every few minutes.
- Ice appears on accessible HVAC lines or equipment.
- Water collects around the indoor cooling equipment.
- One room remains much hotter than the rest of the home.
- Lights dim or electrical circuits behave unusually when the system starts.
- The outdoor unit produces grinding, banging or repeated struggling sounds.
What to document before requesting help
Clear information can help an HVAC professional, electrician, property manager or utility understand whether the problem involves cooling performance, airflow, electricity or the building enclosure.
Indoor temperature
Record temperatures in representative rooms and the time of each reading.
Outdoor conditions
Note the approximate outdoor temperature, humidity, sunlight and duration of the heat event.
Thermostat settings
Record the operating mode, fan setting, selected temperature and displayed indoor temperature.
Cooling runtime
Note whether the system cycles normally, runs continuously or repeatedly starts and stops.
Airflow pattern
Compare vents in comfortable and overheated rooms.
Visible equipment conditions
Photograph accessible ice, water or warning messages without opening the equipment.
Electrical symptoms
Record breaker trips, dimming lights, buzzing or burning odors.
Room conditions
Note window direction, direct sunlight, door position and heat from electronics or appliances.
Service history
Gather maintenance records, previous repairs, equipment age and warranty information.
Record the trend, not only the highest reading. The rate at which indoor temperature rises can help explain how the home performs without normal cooling.
When professional evaluation may be appropriate
The appropriate professional depends on whether the concern involves cooling equipment, electrical service, ductwork, insulation or immediate health and safety.
Qualified HVAC professional
HVAC evaluation may be appropriate for inadequate cooling, short cycling, weak airflow, ice, condensate leakage and unusual equipment sounds.
Licensed electrician
Electrical evaluation is appropriate for repeated breaker trips, damaged wiring, arcing, overheating or unusual voltage symptoms.
Building-performance professional
Testing may help identify duct leakage, air leakage, insulation limitations and pressure imbalances.
Insulation or weatherization professional
Evaluation may be appropriate when upper floors, attic-adjacent rooms or additions overheat despite reasonable airflow.
Property manager or landlord
Renters should report cooling failure, leaks and unsafe indoor conditions through the property’s maintenance process.
Healthcare or emergency professional
Seek medical or emergency assistance promptly when heat-related illness is suspected or a vulnerable person cannot reach a safe environment.
Weak airflow, repeated shutdowns, ice and steadily increasing indoor temperatures may indicate that the system is already struggling.
A practical extreme-heat preparation checklist
- Monitor local heat, air-quality and utility alerts.
- Test the cooling system before the hottest weather arrives.
- Inspect the accessible HVAC filter.
- Clear supply registers and return-air grilles.
- Keep loose vegetation and debris away from the outdoor unit.
- Confirm thermostat schedules and cooling settings.
- Close shades or curtains before strong direct sunlight enters.
- Repair accessible door and window weatherstripping gaps.
- Reduce unnecessary oven, dryer, lighting and electronics use.
- Prepare drinking water, medications and charged communication devices.
- Identify an air-conditioned location and transportation plan.
- Plan for children, older adults, health conditions and pets.
- Review generator placement and carbon-monoxide safety.
- Leave for a cooler location before indoor conditions become dangerous.
Create a written household heat plan that includes cooling locations, transportation, medical contacts, utility numbers, pet arrangements and the point at which the household will relocate.
Extreme heat can become a medical emergency
Do not remain in a dangerously hot home because the cooling system may begin working again later. Move to an air-conditioned location when the home cannot remain safely cool. Never operate generators or fuel-burning outdoor appliances inside a home, garage, basement, crawlspace or enclosed area. Seek emergency medical help when severe heat-related symptoms appear.
Written and reviewed by Nick Fivera Petrovic
Nick is the founder and editor of Home Maintenance Today. He has more than 13 years of experience in SEO, digital publishing, website strategy and working with home-service businesses.
His focus is turning complex home-maintenance topics and reliable source material into practical, easy-to-understand guidance that helps homeowners observe problems, ask better questions and recognize when professional evaluation may be appropriate.
Nick is not a licensed contractor, inspector, engineer, technician or tradesperson.
Sources and further reading
This guide was developed using authoritative guidance about extreme-heat safety, cooling-system maintenance, home cooling, insulation and emergency readiness.
- Ready.gov — Extreme Heat
- Centers for Disease Control and Prevention — Heat and Your Health
- Centers for Disease Control and Prevention — People at Increased Risk for Heat-Related Illness
- Centers for Disease Control and Prevention — Heat and People Without Air Conditioning
- U.S. Department of Energy — Home Cooling
- ENERGY STAR — Heating and Cooling Maintenance Checklist
- ENERGY STAR — Heat and Cool Efficiently
- U.S. Department of Energy — Air Sealing Your Home
- U.S. Department of Energy — Home Insulation
Tell us what happens during the hottest part of the day
Describe the indoor temperature, thermostat settings, airflow, hottest rooms, window exposure and whether the cooling system runs continuously. An online response cannot replace on-site HVAC, electrical, weatherization or medical evaluation.