How to Keep Your Home Cool During a Chicago Heatwave

When a Chicago heatwave hits and the outside temperature spikes into the 90s, your air conditioner is pushed to its limits. You might notice your AC running constantly but not cooling your house to the set temperature—but don’t panic. That doesn’t mean something’s wrong. In fact, in most cases, it means your system is working exactly the way it was designed to.

Why Your Air Conditioner Can’t Reach the Thermostat Setting

If it’s 96°F outside and your thermostat is set to 70°F, but your home is holding around 74–78°F, your AC isn’t broken it’s doing its job.

Most air conditioning systems in Chicagoland aren’t designed to handle a 20-degree drop from the outdoor temperature. That means when it’s in the upper 90s, expecting 70°F indoors just isn’t realistic. HVAC systems are sized for Chicago’s average summer temperatures, not the rare extreme heat we get for a few days each year.

In fact, oversizing your air conditioner to handle those few hot days would cause more problems than it solves. The system would cool your house too fast, which means it would turn off before it removes humidity, resulting in:

• Higher energy bills
• Sticky, uncomfortable air
• Uneven cooling
• Shortened system lifespan due to frequent cycling

A properly sized air conditioner is designed to run longer cycles, which helps remove both heat and moisture making your home feel cooler and more comfortable.