top of page

Why Is My A/C Blowing Warm Air?

Did you turn on your air conditioner for the first time this year only to find out that it’s blowing warm air? Some of the most common causes of your system blowing warm air when it’s not supposed to is a dirty filter, frozen evaporator coil, thermostat setting error or lack of electricity to the outside unit. Today, we are going to be talking about why these problems happen and some ways that they can be fixed.

#1 Dirty Air Filter

If your cooling system has a dirty air filter, it can not properly move air throughout the system. The build up strains the air conditioner and can cause your AC to blow warm air. If you are trying to figure out why your AC is blowing warm air, it’s always best to check your air filter first. If you find that your air filter is dirty, replace it when a new one and see if the warm air issue resolves.

#2 Frozen Evaporator Coils

Your cooling systems evaporator coils extract heat from the air in your home in order to create a cooling effect. Your air conditioner has a pan to catch the condensation that is created from turning warm air into cool air. When moisture collects on the evaporator coils instead, they can freeze. Frozen coils will prevent heat transfer which can cause your air conditioner to blow warm air. You can check this issue by shutting off the power and opening the access door so you can assess the evaporator coils. If you see ice on the coils, you should give them some time to thaw. (this can take up to 24 hours depending on how badly frozen.) Leave your air conditioner off and do not turn it on again until the coils have completely thawed. This problem is usually caused by poor air flow, refrigerant leaks, system damage or other issues. The root of the issue must be solved in order to prevent reoccurring issues.

#3 Thermostat Setting Error

Sometimes it might just be a simple mistake. Make sure to check what your thermostat is set at and the settings to see if this is why your air conditioner is not providing enough cold air. If your thermostat is set ON instead of AUTO on the blower fan settings, it’s running all of the time. In between cooling cycles, the ait you feel from the vents can be warm. If you are having this problem, just simply switch your thermostat settings to say auto.

#4 Lack of Electricity

In a split AC system, both of the indoor and outdoor cycles need to run complete cooling cycles to deliver cooling throughout your home. If the power supply to your home’s outdoor unit is interrupted, it causes the indoor units to be the only one’s working resulting in warm air blowing through the vents. Make sure that your outdoor unit has power and check the electrical panel to verify that the breaker has not been tripped. 515-965-7272 or visit to learn more.

152 views0 comments


bottom of page