Coming home to a cool home on a hot day can be such a relief. That refreshed feeling can quickly turn to despair, however, if your air conditioner is blowing warm or hot air. This can happen when the AC fan is operating but the cooling mechanism has shut down. The problem may be something easy to fix, however. Here is a list of common causes.
The problem can be as simple as your thermostat setting getting inadvertently changed. Check to make sure it is set to “cool,” rather than “heat,” “auto,” or “on.” Any setting but “cool” will cause warm air to blow through the vents. If you have a programmable thermostat, make sure those settings have not changed mistakenly as well.
A dirty air filter will block the flow of air necessary to cool your home. The result may be warm, rather than cool, air coming through the vents. Replace the air filter every one to three months.
Another cause of poor air flow is blocked or closed return vents. Make sure these vents are not covered by furniture or belongings. Vacuum them occasionally to keep them free of dust, dirt and debris.
Air ducts that have gaps or leaks will release cooled air before it makes its way into the living spaces of your home. The result will be warmer temperatures or more energy used to cool the house to the appropriate temperature.
Make sure a tripped circuit breaker or blown fuse hasn’t cut off power to the outdoor unit. If only the indoor unit is working, the system will blow warm air.
If the condenser coils are dirty, they will not function correctly. Schedule a maintenance appointment to have the system, including the coils, professionally cleaned.
If your AC has a refrigerant leak, it will struggle to produce cool air. Check for ice forming on the indoor or outdoor units. To correct this, you need a refrigerant charge. Depending on the age or your system or the seriousness of the leak, it may be time for a replacement.
Scheduling annual maintenance before the start of the cooling season and regularly replacing your air filter are the best ways to keep your AC in good shape all summer long, year after year.