AC Out in a Chicago Heat Wave? Emergency Steps to Take

Stay Safe First

Before troubleshooting the equipment, take care of the people in your home. Heat illness comes on faster than most people expect.

• Move to the lowest, shadiest level of your home, where it's coolest.
• Close blinds and curtains on sun-facing windows to block radiant heat.
• Run fans to move air, and stay hydrated with water — avoid alcohol and caffeine.
• Check on elderly family members and neighbors, and never leave anyone (or a pet) in a hot car or closed room.
• Watch for heat exhaustion or heat stroke — dizziness, nausea, confusion, or a lack of sweating are medical emergencies; call 911.

Quick Checks Before You Call

A few simple things resolve a share of no-cooling calls and cost nothing to try:

• Thermostat: Set it to COOL and several degrees below the current room temperature; replace dead batteries.
• Filter: A clogged filter restricts airflow and can freeze the coil — replace it if it's dirty.
• Breaker: Check whether the AC breaker has tripped; reset it once. If it trips again, stop and call.
• Outdoor unit: Make sure it's running and not buried in debris, tall grass, or cottonwood fluff.
• Vents: Confirm supply registers are open and return vents aren't blocked by furniture.

Why AC Fails During Heat Waves

Air conditioners break down during heat waves for a simple reason: that's when they run hardest and longest. A marginal capacitor, a weak contactor, low refrigerant from a slow leak, or a dirty condenser coil that limped along on mild days finally gives out under peak demand.

Extended run times also freeze evaporator coils when airflow is restricted — which is why a dirty filter or blocked vents can leave you with an iced-up system and no cooling at all. If you see ice on the refrigerant lines, turn the system off and let it thaw while you arrange service.

When to Call for Emergency AC Repair

If your quick checks don't restore cooling, call for service rather than letting the house keep heating up — particularly if you have vulnerable residents. During heat advisories, we prioritize no-cooling emergencies.

Polar Refrigeration & Air Control provides 24/7 emergency AC repair across Chicago and the suburbs, with a 60-minute call-back and same-day dispatch whenever weather and volume allow. Because the most common heat-wave failures are parts we carry — capacitors, contactors, fan motors — a large share of emergency calls are repaired on the first visit.

What Actually Fails During a Chicago Heat Wave

When we get slammed with no-cooling calls, it's rarely a mystery. The parts that fail first under peak load are the run capacitor and the contactor — cheap components that limped along on mild days and finally gave out at 95°F. A weak capacitor is often a 20-minute fix once it's diagnosed, which is why so many heat-wave calls are solved on the first visit.

The other big one is a frozen coil from restricted airflow. A dirty filter or a closed-off return starves the system, the coil ices over, and suddenly there's no cooling at all. If you see ice on the lines, shut the AC off, let it thaw, and swap the filter before you call — it saves the compressor and sometimes the service call.