If your heater is blowing out cold air instead of the heat you need, there may be a simple explanation for why this is happening. Follow these steps to rule out the possibilities and address the problem.
Step 1: Turn the thermostat up to trigger another heating cycle.
Sometimes the air blown out at the end of a heating cycle is cool because the heating element has turned off but the fan is still running. Turn your thermostat up a few degrees to trigger the heat to come back on. Wait and feel whether the air that comes out is hot or cold. If it heats up, you can chalk this one up to the timing of your fan.
If it bothers you that the fan runs longer than the heating element, you can have your HVAC contractor adjust the fan timing so this doesn't happen anymore. If the air that comes out after you turn the thermostat up is also cold, then proceed to the next step.
Step 2: Check to see whether there's a problem with your gas supply.
If you have other gas appliances, are they working? If not, you have a problem with your gas supply and should call your local gas company to sort it out. Since most blowers are electric, your heating system would still blow out air, even if the gas supply was turned off—that air just wouldn't be warm. If all of your other gas appliances are working fine, then the problem is probably with the furnace itself.
Step 3: Make sure your pilot light is on.
If you have an older furnace with a pilot light, check to make sure the pilot light is on. Sometimes, a pilot light may be blown out by a draft or slight break in the gas supply. If the pilot light appears to have been blown out, use a long lighter to carefully re-light it. In the case that it can't be re-lit, it's time to call an HVAC specialist such as CampbellCare Plumbing Heating & Air.
If you have a newer heater with an electric ignition, make sure the unit is plugged in. Electronic heating elements do tend to break after 3–5 years, so if your pilot is plugged in but not functioning, it's probably time to call your HVAC technician for a replacement.
By following the steps above before calling your HVAC technician, you can avoid the embarrassment of calling in for a minor, easily-fixed problem. Sometimes cold air coming from your heating vents is nothing to worry about, but other times, it's a sign that your home is about to get really chilly if you don't have your furnace repaired promptly.