Is Your AC Blowing Warm Air? Here Are The Possible Causes

Experiencing AC blowing warm or hot air? Explore the possible causes and find solutions. Get expert assistance at Sandium to restore if your AC is blowing hot air.

Updated on Oct 23, 2023
5 min read
Is Your AC Blowing Warm Air? Here Are The Possible Causes

Most times an air conditioning unit blows warm air when the fan is operating fine, but something within the cooling mechanism is shutting down or malfunctioning. There can be several causes for this. Some of these are explained below:

1. Thermostat Problems

The first thing to do when your AC starts throwing warm air is to check the thermostat. Thermostat set high is more common than you would think. Kids accidentally hit it, babies tamper with it, or your partner may turn it off wanting a warmer home. Make sure the fan is set to AUTO and the thermostat to COOL. Also, check the temperature to ensure it is lower than room temperature.

2. Choked Filter

Reduced air flow is another common problem that could impede the cooling mechanism of your AC. Your conditioner needs warm air to flow over the coils for it to function properly. The filter is designed to remove contaminants, including dust from the air flowing in. However, a clogged filter would completely block air and when this happens the coils are unable to remove heat. This would lead to the fan system to throw the heat out of the vents.It is most likely the air filter if you have not had your system maintained in a while. Check the air filter and change it or clean it.

3. Return Vents Are Blocked Or Closed

Another reason for warm air to blow in could be closed vent grilles. Maybe you closed them over the winter and forgot to re-open them. Look for furniture and other obstructions that may be blocking the vents. Make sure that all returns and registers are open to allow for free air flow.

4. Leaky or Disconnected Ducts

It is quite possible that you have a duct issue that is leaking cool air. This would need you to call an HVAC expert. Maybe the duct is disconnected completely which means return air is not going back to the unit or cooled supply air is getting wasted within the dry wall or attic.

5. Outdoor Unit Has No Power

Most air conditioning units have an indoor air handler unit and an outdoor cooling unit. The blower system or fan would continue blowing air within the living space if the indoor unit is functioning. However, if the outdoor unit has no problem or is malfunctioning there will be no cooling. This will cause warm air to blow through the vents.

This can take place when a fuse blows or the circuit breaker trips. You need to call in the experts if you suspect an electrical issue. Never try to experiment with live voltage on your own. You could check the emergency shutoff switch though to make sure it hasn’t been switched off accidentally.

6. Condenser Coils are Dirty

An important function of the condenser unit is to release hot air outside the building. This is done by the condenser coil. However, if the condenser unit is exposed to the elements, is caked with dirt or grime, or covered with trash and leaves, then the coil cannot function properly. This will hamper your system’s cooling as well which no Bay Area resident wants to deal with.

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