In the heat of the summer, nothing’s worse than thinking your AC is running, only to find out it’s blowing warm or room-temperature air. There are a few things that can cause this, some of which you can correct yourself. Others will require an HVAC technician.
Check Your Filters: One simple thing that can cause issues with the proper functioning of your AC unit is improper airflow, which is typically caused by dirty filters. You should have a filter inside the grille of each return vent in your home. In addition, most central units also have a filter in them on the return side right before the air enters the evaporator coil. They are easily removed and changed. Most filters require changing at least every 90 days and are available at any home improvement store.
Check Your Thermostat: This may seem an obvious first choice, but it can be overlooked. With so many programmable thermostats in use now, they often change temperature settings throughout the day. If a program is amiss, that could be the issue. If something has gone wrong with the calibration of your thermostat, it may not be reading correctly. Try setting it a few degrees cooler to see if that makes a difference. Lastly, check to see if there’s anything located very close to your thermostat that may be throwing off it’s temperature reading.
Check the Condenser: Make sure the condenser unit isn’t covered with high grass or weeds or otherwise blocked. This will create an airflow issue and can damage the unit. Also look through the top for a visual inspection of the fan and the coil inside. If the fan isn’t moving or if you see any ice or freezing on the coil, shut your AC off and call an HVAC technician. If there is freezing on the coil, you are likely low on Freon coolant. Recharging the unit with Freon requires a licensed HVAC contractor. Be sure to keep an eye on it even after recharging. If the coil freezes again, you have a leak somewhere and may need either a new evaporator coil or a whole new AC unit.