The air flowing out of your air vents should feel refreshing and cool. When it feels warm or lukewarm, you know there’s a problem. While you may need to contact an HVAC technician for AC repair downriver MI , the good news is that you can sometimes troubleshoot this issue and fix it yourself.

1. Check the Thermostat

Even if you think your thermostat is set correctly, check it anyway, especially if you live in a house with others who may have “adjusted” the thermostat. It is possible that only the fan of your air conditioning system is running and circulating warm air in your home. If your thermostat says “on”, that means the system fan is on. This means that the fan will push air through the ducts and out of the vents, even if the indoor unit is not cooling it. The thermostat must be set to “cool” or “auto” for your air conditioner to cool and dehumidify your indoor air while the fan circulates.


2. Make Sure The Outdoor Unit Is Powered

Your air conditioner is a high-powered device, which means it uses a lot of energy to run. If a short-term overvoltage occurs, it may cause the outdoor unit to trip the circuit breaker. If your air conditioner is blowing warm air, check the circuit breaker panel to see if the switch is off. Also, if your AC unit has had work done recently, the technician most likely turned off the outdoor unit at some point while doing the work. It’s possible that the technician forgot to turn the outdoor unit back on, so check the box on the wall next to your unit to make sure the device is powered.

3. Make Sure Nothing Is Pressing The Outdoor Unit

The outdoor unit of your air conditioner (condenser) releases heat. Therefore, it needs space for ventilation on the sides and top. (This is one of the reasons we cringe whenever we see a unit installed under a deck or in a crawl space.) Make sure the condenser has at least 1 foot of space around it and at least 5 feet of vertical space. Remove all weeds and trim any bushes or hedges growing against the facility.

4. Check the Air Filter

Most manufacturers state that disposable air filters are good for up to 90 days – the key phrase being “until”. If you use the air conditioner during the day for weeks, the filter will get dirty before the 90 days are up. If you have pets, the filter will get dirty even faster. So how does a dirty air filter cause warm air to come out of the air conditioner? When the air filter is covered in dust, it blocks the flow of air through your air conditioning system. This creates some problems:


  • The air conditioning unit has to work extremely hard to send out cold air.
  • Not enough hot air is blowing through the internal heat exchanger (or evaporator coil) that contains the refrigerant.

As a result, parts of your air conditioner can overheat, while condensation on the evaporator coil can freeze. Once the coil freezes, it cannot effectively cool the air in the room. Additionally, a frozen evaporator coil puts the system’s compressor at risk of overheating and death.