Have you noticed your furnace is running, but the air that’s blowing out of your vents seems cool? There are several possible causes for a furnace blowing cold air, but the following are 5 common causes you can oftentimes fix yourself.
Thermostat Fan Set to “On”
Take a look at your thermostat and make sure the fan setting is on “Auto” rather than “ON.” When your thermostat fan setting is set to “ON”, the fan on your furnace will blow continuously, even when the furnace isn’t actually heating your air.
Dirty Air Filter
A dirty air filter restricts airflow, causing the furnace to stay on longer in order to heat your home. This occurs until eventually, your furnace will just overheat. Make sure you are checking your filters regularly, most disposable filters need to be changed every 2-3 months.
Warm air is distributed through your home via your ducts. If your ducts are leaking or damaged cold air from your attic or crawlspace will infiltrate your duct system, causing the treated air to escape and be replaced with untreated, filthy, air.