Why is My AC Blowing Hot Air? A Pittsburgh Tech Answers

In the heat of a Pittsburgh summer, the last thing you want to deal with is an AC that is blowing hot air. There could be many reasons that your air conditioning unit has decided to not perform its intended task. This could range from an easy fix to something more serious that you may want to call a professional in to look at or fix.

A few reasons your AC may be blowing hot air include:

  • The wrong thermostat or fan setting
  • A refrigerant leak
  • A dirty/clogged outdoor (condenser) unit

Below, we’ll discuss each of these issues and what steps you can take to get your AC blowing cool air again.

Don’t want to take the time to troubleshoot this yourself? That’s what our team of pros is here for. We are happy to take a look at your AC and determine what the issue is. Learn more about our AC repair process or…

Reason #1: Wrong thermostat or fan setting

We know this sounds crazy, but it happens! If your thermostat or fan is on the wrong setting, it could cause your AC system to blow unconditioned or even heated air into your home.

The fix:

1. Make sure that your thermostat is set to COOL, not HEAT.

2. Ensure that your fan is set to AUTO, not ON.

The first one probably seems obvious, but why would we tell you to set your fan to AUTO instead of ON? Great question!

When your fan setting is on AUTO, it will only blow air into your home when that air has been cooled by your AC unit. When your fan setting is ON, it will cause the fan to run continuously, even when the air hasn’t been conditioned by your AC system. For maximum cooling (and to stop your AC from blowing warm air into your home), make sure your fan is set to AUTO.

Reason #2: Refrigerant leak

Your AC cools your home by drawing in warm air from your home, stripping that air of heat, and then blowing that cool air back into your home.

Your AC absorbs heat via refrigerant, which is a liquid/gas that is circulated between your indoor and outdoor units. At the indoor unit, the refrigerant absorbs heat. At the outdoor unit, the refrigerant dumps that heat into the outdoor air.

A diagram showing how refrigerant absorbs heat and removes it from your home.

If there is a leak in your refrigerant line, your AC can’t absorb as much heat. As a result, your AC could be pumping warm air into your home instead of cool air.

The fix: Hire a professional. If you do have a refrigerant leak (or your refrigerant levels are low) a professional will need to repair the leak and refill your refrigerant.

Note: If a technician wants to refill your refrigerant without repairing a leak, find a different technician. If refrigerant levels are low, it means there is a leak in your system, and you’ll be wasting money if you refill your refrigerant without repairing the leak first.

Reason #3: Dirty/blocked outdoor (condenser) unit

Like we mentioned above, your AC cools your home by removing heat and dumping it outside via your outdoor or condenser unit.

Here’s the catch: If your condenser unit is dirty or clogged, it can’t get rid of heat as well as it needs to, and that means refrigerant can’t pick up as much heat as it needs to. The bottom line is your AC can’t cool your home’s air, and it may be the reason you’re feeling warm air coming from your AC vents.

Example of a condenser that is blocked with debris

The fix: Have your outdoor unit cleaned by a professional. To ensure your outdoor unit is clean and running efficiently, you should have a professional clean the interior parts of the outdoor unit.

While cleaning your outdoor unit may seem easy, attempting to clean the coils and other parts of the indoor unit yourself could result in long-term damage to your AC system.

You can, however, remove debris from the outside of the unit and regularly clear away shrubs and trees that grow close to the unit (A good rule-of-thumb is to keep a 3 ft. perimeter around your outdoor unit).

Ready for cool air again? Hire Pittsburgh’s best… us!

If you’re tired of your AC blowing warm air into your home, call us. Our team of pros is trained to diagnose and repair any AC system quickly and correctly. If you want same-day service that’s 100% guaranteed, we’re the team to call.