Troubleshooting & how-to · August 2026 · HVAC Iowa City
AC not cooling? Check these five things before you call
Every summer in Iowa City we take no-cooling calls that end happily on the phone, without a truck ever leaving. That's because a surprising share of dead air conditioners aren't dead at all. Before you pay anyone anything, run this five-minute checklist. It's the same one we walk callers through.
First, the thermostat. Confirm it's set to cool, the temperature is set below the current room reading, and the fan is on auto. If the screen is blank or dim, change the batteries. It feels too simple to be the answer, which is exactly why it so often is.
Second, the breaker. Find your electrical panel and look for a tripped breaker labeled for the air conditioner or condenser. A tripped breaker sits between on and off. Flip it fully off, then back on, once. If it trips again, stop there and call, because a breaker that keeps tripping is telling you something is genuinely wrong.
Third, the filter. A clogged filter chokes airflow until the indoor coil freezes into a block of ice, and a frozen coil can't cool anything. If the filter looks gray and furry, swap it. If you see ice or heavy frost on the copper lines, turn the system off and let it thaw for a few hours before trying again.
Fourth, the outdoor unit. Walk outside and look at the condenser. In an Iowa City June it can be wearing a coat of cottonwood fluff, grass clippings, or leaves. Gently rinse the fins with a garden hose, from the top down, with the system off. A condenser that can't breathe can't shed heat.
Fifth, your vents. Make sure supply vents are open and nothing is parked in front of the returns. A room-by-room comfort problem is often an airflow problem, not an equipment problem.
If you've run all five and the house is still warm, now it's a real service call, and you've already saved time: telling us what you checked helps us diagnose faster. One safety note: never open the sealed refrigerant system or the electrical cabinet. That's where DIY stops and we start. Call, and you'll get an honest read and a price in writing before any work.