Why is My Home AC Blowing Warm Air?

Home repairs can be costly. If you have a problem with your air conditioner, being able to fix it yourself will help save you money.

A common problem, that is aggravating in hot weather, is having your AC unit blow warm air. While there are many reasons why this could be happening, we’ll take a look at the most common causes that you can diagnose and most likely fix on your own.

The thermostat is set incorrectly

Before you begin taking your trouble-shooting journey, check the most obvious possibility first. Is your thermostat set to cool and not to heat? It may sound silly, but it’s worth checking because someone may have accidentally bumped up against it.

Also check to see if you have your thermostat set to “auto” or “on”. If it’s set to “on”, the fan will be blowing even when the air conditioner isn’t actually cooling. Your AC will blow out warmer air when the outside unit isn’t running.

There’s a restriction in airflow

If the airflow to and from your unit is being restricted, there won’t be enough air coming out of the vents to cool your home. Having a restricted airflow can also cause the compressor, which is responsible for moving the refrigerant, in your air conditioner’s outside unit to freeze up.

There are two common reasons for restricted airflow:

  • The air filter hasn’t been replaced in a long time (replace it every 1-3 months)
  • Your condenser coil is dirty and needs maintenance.

Clean your condenser coil

Your AC system has two main parts – an indoor and an outdoor unit. The indoor unit houses the fan that blows air through your home, but it depends on the outdoor part. The condenser, in the outside unit, sucks air in through the sides and rejects it out through the top. It basically absorbs heat from inside your house, brings it outside through the refrigerant and air blows through the coils. Because the air is being sucked in, the coils will eventually get clogged up with various particles such as dust, leaves or grass. Take the top off your unit and hose the coils down with regular water pressure. Make sure you have the power turned off before doing this.

The outside unit isn’t getting electricity

Check your circuit breaker or fuse panel to make sure the circuit is supplying electricity to the outside unit. If there is air blowing out of your vents but it’s not cold, it could be that the circuit breaker has tripped or the fuse has blown on the electrical circuit that provides electricity to your outdoor unit.

Other causes

So, if your air conditioner is blowing warm or hot air, and you’ve run through the possibilities for fixing it inside, your problem most likely lies in the outside unit. Check also if your refrigerant level is low. Read the label on the unit to determine which type of coolant to use. Turn off your system, and put on your goggles, gloves and a breathing mask before going any further.

There could be numerous possibilities why your home AC unit is not cooling as it should be. If you have run through this trouble shooting guide without finding a solution, it’s probably a good idea to now call a professional for help.