If you’re wondering how to keep your house cool during a heat wave, you’re not alone. As temperatures climb across Chicago and the surrounding suburbs, your air conditioner has to work much harder to keep your home comfortable. During periods of extreme heat, it’s normal for your AC to run longer than usual as it removes both heat and humidity from your home. Understanding what to expect—and taking a few simple preventative steps—can help improve your system’s performance, reduce energy costs, and minimize the risk of an unexpected breakdown.
Quick Answer: How Do You Keep Your House Cool During a Heat Wave?
To help your air conditioner perform its best during extreme heat:
- Replace a dirty air filter
- Keep your thermostat set between 75° and 78°F
- Close blinds and curtains during the hottest part of the day
- Keep your outdoor AC unit free of debris
- Avoid using heat-producing appliances during the afternoon
- Check your circuit breaker if your AC suddenly stops working
These simple steps can improve comfort while reducing unnecessary stress on your cooling system.
Is It Normal for My AC to Run Constantly During a Heat Wave?
Yes.
During periods of extreme heat, your air conditioner may run almost continuously to maintain your home’s temperature.
Most residential air conditioning systems are designed to cool your home approximately 15 to 20 degrees below the outdoor temperature.
For example:
- If it’s 95°F outside, your home may naturally stabilize around 75°–80°F, depending on insulation, sun exposure, and your system’s condition.
Longer run times don’t necessarily mean your air conditioner is failing—they often mean it’s doing exactly what it was designed to do.
1. Replace a Dirty Air Filter
A clogged air filter is one of the most common causes of poor cooling performance.
A dirty filter restricts airflow, making your air conditioner work harder while delivering less cool air throughout your home.
During periods of heavy AC use, check your filter monthly and replace it if it appears dirty.
If you’re experiencing reduced airflow or uneven cooling, it may be time to schedule a professional air conditioning inspection.
2. Set Your Thermostat Between 75° and 78°F
One of the biggest mistakes homeowners make during a heat wave is constantly adjusting the thermostat.
Instead:
- Choose a comfortable temperature between 75° and 78°F
- Leave it there
- Avoid making frequent changes
Constant adjustments won’t cool your home faster—they simply force your system to run longer.
A steady temperature helps your AC operate more efficiently.
3. Keep Sunlight Out
Direct sunlight can significantly increase indoor temperatures.
To reduce heat gain:
- Close blinds
- Close curtains
- Focus on south- and west-facing windows during the afternoon
Blocking sunlight reduces the amount of heat your air conditioner must remove.
4. Keep the Outdoor Unit Clear
Your outdoor condenser needs unrestricted airflow.
Check that it’s free from:
- Tall grass
- Weeds
- Leaves
- Patio furniture
- Toys
- Landscaping materials
Keeping at least two feet of clearance around the unit helps improve efficiency and system performance.
5. Limit Heat-Producing Appliances
Appliances generate surprising amounts of indoor heat.
During the hottest hours of the day, try to limit use of:
- Ovens
- Stovetops
- Clothes dryers
- Dishwashers
Instead, cook outdoors, use a microwave, or run appliances later in the evening.
Reducing indoor heat makes it easier for your AC to maintain a comfortable temperature.
6. If Your AC Stops Working, Check the Breaker First
Before calling for service, take a quick look at your home’s electrical panel.
Sometimes a tripped breaker can prevent your air conditioner from starting.
If the breaker has tripped:
- Reset it once
- Wait several minutes
- Try restarting your system
If it trips again or your AC still won’t turn on, stop resetting the breaker and schedule professional AC repair.
Repeated breaker trips often indicate a larger electrical or mechanical issue.
Signs Your AC May Need Professional Service
While longer run times are normal during extreme heat, these warning signs are not:
- Warm air coming from vents
- Weak airflow
- Ice forming on refrigerant lines
- Strange noises
- Water leaking around your indoor unit
- Your home never gets close to the thermostat setting
If you notice any of these issues, it’s best to have your system inspected before the problem becomes more expensive.
Frequently Asked Questions
Why won’t my house cool below 78 degrees?
During extreme heat, most residential air conditioners are only designed to cool your home about 15–20 degrees below the outdoor temperature. If it’s 98°F outside, maintaining 78°F indoors may be normal.
Should I turn my thermostat lower during a heat wave?
No. Setting your thermostat significantly lower won’t cool your home faster. It simply causes your system to run longer.
How often should I replace my AC filter during summer?
Check your filter every month during heavy cooling season. Replace it whenever it appears dirty, especially if you have pets or allergies.
Why is my AC running all day?
Continuous operation is common during extreme heat. If your home is still cooling and the system is maintaining temperature, it’s likely operating normally.
When should I call an HVAC professional?
Call a professional if your system is blowing warm air, repeatedly trips the breaker, freezes up, makes unusual noises, or cannot maintain a comfortable indoor temperature.
Stay Ahead of the Heat
Heat waves put every air conditioner under additional stress.
A little preventative maintenance can help improve efficiency, lower energy costs, and reduce the chances of an unexpected breakdown when you need your AC the most.
If your system isn’t keeping up, the team at NextGen Mechanical is here to help with expert diagnostics, repairs, maintenance, and system replacements throughout Chicago and the surrounding suburbs.
