It's July, the AC is running, and the house is still 80 degrees. Before you call anyone, there are a few things you can check yourself. Some of them fix the problem on the spot. The rest tell you (and us) where to look.
1. Check the thermostat
Make sure it's set to Cool, the temperature is set below the room temperature, and the fan is on Auto, not On. If the screen is blank, change the batteries. It sounds too simple, but it's one of the most common no-cool calls.
2. Look at the air filter
A clogged filter is like trying to breathe through a pillow. The system runs, but almost no air gets through. Pull it out and hold it up to a light. If you can't see light through it, replace it. In Louisiana, check it every month.
3. Check the breakers
Your AC usually has two breakers: one for the outdoor unit and one for the indoor unit. If one is tripped, reset it once. If it trips again, leave it off and call. A breaker that keeps tripping is telling you something is wrong.
4. Go look at the outdoor unit
With the system running, the big fan on top should be spinning and you should hear the compressor humming. If the fan isn't spinning, or it hums but doesn't start, turn the system off at the thermostat. That's often a failed capacitor or contactor, and running it that way can damage the compressor.
While you're out there, look at the coil (the metal fins around the sides). If it's packed with leaves, grass, or dirt, it can't get rid of heat. Here's what that can look like.
5. Look for ice
Ice on the copper lines or on the indoor unit means the coil is too cold, usually from poor airflow or low refrigerant. Turn the system to Off and the fan to On for a few hours to thaw it. Then call, because the ice will come back until the cause is fixed.
6. Check the drain
Many systems have a float switch that shuts the AC off when the drain line backs up, so your ceiling doesn't flood. If the drain pan under the indoor unit is full of water, that's probably why the system stopped cooling.
7. Walk the vents
If some rooms are cool and others aren't, the problem may be ductwork, not the AC. In our attics, a torn or disconnected duct can dump cold air into the attic instead of the bedroom. We find this all the time.
When to call
- The breaker trips again after you reset it
- The outdoor fan won't spin, or the unit hums but won't start
- You see ice, or the ice keeps coming back
- You smell burning or hear grinding or squealing
- You've checked everything above and it still won't cool
When we come out, we test pressures, temperatures, and electrical parts so we're fixing the real problem, and you get the price before we start. See our AC repair page.