Furnace Blowing Cold Air: What Should I Check?

Is your furnace blowing cold air instead of warm air? Check these basic issues before calling in a professional technician!

Wait
This is an important step, especially if you have a new furnace or a new home. Sometimes furnaces (especially older models) take a few minutes to heat up and start creating heat where you can really feel the difference. But because the fan kicks on early, current-temperature air blows, which feels cold on the skin. Wait a few minutes to see if it begins to heat.

Check Your Thermostat
The most common cause of surprise cold air from your vents is a thermostat issue. Take a look at your thermostat and make sure of two things:

  1. It's set at the right temperature. Anything from an accidental bump to mischievous kids can change your temperature settings. Make sure the thermostat numbers are correct.
  2. It is set to "auto." Setting the fan to "on" will force it to blow cold air even when the furnace isn't on. Set it to "auto" instead.


Look for Open Panels
All right, time for a look at the furnace itself! Check for any open or loose panels, and make sure any panels or doors are shut. A furnace blowing cold air could be caused by a partly-open panel, which sets internal furnace sensors into "danger" mode and prevents the furnace from lighting until everything is closed up.

Take a Look at Your Pilot Light (if applicable)
Some older gas furnaces use pilot lights to ignite the incoming stream of gas. If that pilot light shuts off, the furnace typically won't operate – to avoid flooding the fire chamber with unlit gas. The pilot light probably needs to be ignited again. If you aren't sure what to look for or how to do this, call up a professional and ask for an inspection.

Look at your Furnace Filter
You may know that most standard 1 inch furnace filters should be replaced several times a year. What you may not know is that leaving a dirty filter can have unfortunate consequences. If furnace airflow becomes too clogged up, the furnace will shut itself down out on safety protection, which leaves the fan blowing nothing but cold air. Replace those filters!

If you do need help with a more detailed problem, trust the technicians at Ragsdale, and call us with any of your heating questions!

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