AC Running but Not Cooling? Here's What to Check
Published October 14, 2026 · More articles
It's a muggy Akron afternoon, the thermostat says 72, and the house is 79 and climbing. You can hear the AC running, but the air from the vents is barely cool. Here's how to narrow it down.
Check These First (5 Minutes)
- Thermostat: set to "cool," set below room temperature, and the fan on "auto."
- Filter: pull it out. If you can't see light through it, replace it.
- Breakers: check the AC breaker in the panel and the disconnect box by the outdoor unit.
- Outdoor unit: is the fan spinning? Is the coil packed with grass clippings or cottonwood fluff?
- Vents and returns: make sure they're open and not blocked by furniture.
The 7 Most Common Causes
1. A clogged air filter
A filter packed with dust chokes airflow over the indoor coil. Less air means less cooling, and it can freeze the coil.
2. A dirty outdoor coil
The condenser coil has to shed heat outside. Dirt, grass and seeds insulate it, so the system can't get rid of heat on hot days.
3. A failed capacitor
The capacitor helps start the compressor and fan. When it fails, the outdoor unit may hum without starting, or the fan won't spin. It's one of the most common AC repairs.
4. A frozen evaporator coil
Ice on the copper lines or indoor coil blocks cooling. Turn the AC off and the fan on to thaw it, then fix the cause, usually airflow or low refrigerant.
5. Low refrigerant from a leak
An AC doesn't use up refrigerant. If it's low, there's a leak. Topping it off without fixing the leak just delays the next breakdown.
6. A clogged condensate drain
Many systems have a safety switch that shuts the AC off when the drain backs up. Look for water around the indoor unit.
7. An undersized or aging system
If the AC runs all day on hot days and the house stays clammy, the system may be too small for the house, or worn out.
When to Call
- The outdoor unit hums but doesn't start
- There's ice on the lines
- The breaker trips again after you reset it
- Air from the vents is warm after you've checked the filter and thermostat
- You hear grinding, screeching or buzzing
Repair or Replace?
Capacitors, contactors and drains are routine repairs. A failed compressor or a leak on an older R-22 system is often the point where replacement makes more sense. → AC replacement
Frequently Asked Questions
How much cooler should the air from my vents be?
Can I add refrigerant myself?
Is it an emergency?
Get Your Heat or AC Running Again
Don't sit through a cold snap or a heat wave with a system that isn't working. Tell us what it's doing. Call (234) 271-3726 or send the form.
- Diagnosis first, so you only pay for the repair you need
- Repair-or-replace options explained plainly
- Serving Akron & Summit County