Why Is My A/C Blowing Hot Air?

There’s nothing like getting home on a hot day to drink a nice cold beverage and enjoy the cool air conditioning blowing through your home… until it starts blowing hot air! Here are some reasons your A/C might not be working properly.


Dirty Air Filters

When the cooling system’s filter gets dirty, the External link opens in new tab or windowair conditioning can’t properly move air throughout the system. This issue will cause strain on your air conditioner and make it blow hot air.


When you’re working out what’s wrong with your AC, check the air filter first to see if it’s clean. If it’s dirty, replace it with a new, clean filter, and see if the hot air problem is solved.


Frozen Evaporator Coils

The evaporator coils extract heat from the air in the home to start the cooling process. A bi-product of this process is condensation, which is why air conditioners have a drip pan and condensation drain to catch the moisture that has been detected and get it out of the system. These coils can freeze, which prevents heat transfer, so you will get warm air blowing from the AC system.


Shut the power off to the AC system and open the access door in the interior system component to get access to the evaporator coils. If you can see ice or frost on the coils, then leave them to thaw. This could take up to 24 hours, depending on how severe the freeze is. Leave the AC off and don’t turn it back on until the coils are thawed.


You can speed up the thaw with a heat gun or a hairdryer. Carefully pass the heat over the ice to thaw the coils. Make sure the AC system’s drip pan and condensation drain aren’t clogged, so they can remove this moisture.


Frozen evaporator coils can be caused by poor airflow, refrigerant leaks, or system damage. Try to find the root of the problem, so it can’t become a recurring issue.


Thermostat Setting Errors

Sometimes, a small mistake with the thermostat can cause your AC to not give you cold air. If the blower fan is set to ‘on’ instead of ‘auto’, it will run all the time, instead of only during a cooling cycle. In between cooling cycles, the air you feel from the vents will be warm.


Before you call in AC repair, check your thermostat settings if it’s blowing hot air. Make sure the fan is set to ‘auto’ instead of ‘on’. Check it’s set to ‘cool’!


Lack Of Electricity

If you have a split air conditioning system, both the indoor and outdoor components need to run to complete cooling cycles and deliver cooling to your home. If the power supply has been interrupted to the outdoor unit, then the indoor components will be the only ones working, causing warm air to blow from the vents.


Check the outdoor unit has power. You can also check your house’s electrical panel to ensure the breaker hasn’t tripped. Reset it if you need to. Check the on/off switch for the outdoor AC unit to make sure it is turned on.