Why is your heater blowing cold air? There are a few possible reasons this could be happening.
The cause of many heating and cooling issues; an old or dirty air filter. Make sure to check your filters and change them regularly. If your air filters are old or dirty, it can cause the heater to overheat. The heater overheats because it is not getting proper ventilation.
Check your thermostat. If you share a home with someone, people mess with thermostats daily. If someone changed the setting of the fan from “auto” to “on” the fan will run even when the heater is not running. This results in cooler air being blown from your vents. Another thermostat issue could be low batteries.
Pilot Light is Out
If your pilot light has gone out, you can follow manufacturer instructions and relight it. If you are uncomfortable doing it yourself call an HVAC specialist to take care of it for you.
Faulty Gas Valve
If you have tried relighting the pilot light and it will not stay lit, you may have a faulty valve. This happens if your system has not been cleaned for a while, resulting in dirt and debris buildup. If this is your issue have an HVAC specialist out to clean your system and give it a good checkup.
Your air ducts are what carries air around your home or building. If the ducts have a leak the hot air will escape through them. This would result in cool or cold air coming from your vents. If you believe this is your issue, have a specialist out to inspect your ducts and furnace.