Why is my furnace blowing cold air?

The nights are getting cooler which means you’ll be using your heater more. Nothing is worse than receiving a blast of cold air when you are expecting warm comfort. If you are getting cold air, it is probably due to the following reasons:

  1. Thermostat setting – make sure your thermostat is set to the “heat” position and not cool. After a long summer, a lot of people forget to make the switch. Also check to make sure your fan is not set to the “on” position and you are using the “automatic” setting instead. If the fan is set to “on” your fan will run continuously regardless if your furnace is producing heat and the air being pushed into your home will be cold. You’ll also save money by not having the fan continuously on.
  2. Need to adjust the fan limit switch – if the air coming from you vents starts cool, then warms up only to get cool again before the fan cuts off between cycles, the fan limit switch needs adjustment. It is located just under the hood of your furnace and indicates when your furnace blower should come on. When the fan limit switch is set correctly, you should never feel cold air coming from your vents when the heat is on.
  3. You have leaky air ducts – this happens when your heating system struggles to reach the desired thermostat temperature, you notice a rise in your electric bill and your home is getting really dusty. This problem needs a professional to inspect for leaks and provide you with the best solution.
  4. Your furnace is over-heating when the furnace blows hot but quickly turns to cold and then shuts off altogether probably as a result of the exchanger getting too hot causing the fan limit switch to shut off. Check to see your air filter needs replacing and make sure all supply vents are open.

If you are still getting cold air from your unit, contact Family Air to troubleshoot your problem. We’ll get your furnace working promptly again and put you back in warm comfort!

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