Guides and Tips

Why is my furnace not blowing hot air?

July 16, 2022
Why is my furnace not blowing hot air

A furnace not blowing hot air can have a major or minor defect that has to be repaired soon so you can be cozy and comfortable at home.

Read our simple guide to know some of the common causes of a furnace pumping chilly air. We will also suggest helpful DIY tips so that you won’t need to hire an HVAC technician and spend a lot of money.

1) Incorrect Thermostat Setting

Incorrect Thermostat Setting

It’s always wise to inspect the furnace yourself to the extent of your technical ability before getting a qualified pro.

The first thing you can check is the thermostat setting. Maybe the temperature has been altered by someone, or maybe the fan mode is set to “on” when it should have been “auto.” These are some possible reasons why your furnace isn’t producing adequate heat in your home.

Or the problem may have something to do with your thermostat—and not the furnace itself—since the former isn’t compatible with the latter or the wiring job for it had been installed incorrectly.

2) Clogged or Dirty Air Filter

Clogged or Dirty Air Filter

Another possible reason your furnace isn’t working well is a dirty or clogged filter, which prevents hot air from flowing into your room.

In fact, some furnace models feature an auto-shut-off system. As soon as they detect the filter is clogged, it stops on its own to prevent the furnace from needlessly overheating.

Fortunately, this is quite simple to fix. All you have to do is buy a new filter from a local appliance store and change the old one with it.

Then, wait for half an hour or longer and see if you’re getting warm air in the room. But don’t worry if that doesn’t solve the problem, as changing your filter will still do you good.

3) Energy Source Problems

Energy Source Problems

If both the thermostat and filter are fine, fret not, as your furnace may have another easy-to-fix problem. 

That is the fuel or electricity isn’t coming in for the unit to deliver heat throughout your house. So here’s what you should do based on your specific furnace type:

  • Electric furnace – Check whether or not the furnace switch on the breaker is open. Aside from that, check if the furnace itself is switched on afterward.
  • Gas furnace – Ensure that the gas valve is open so the fuel can travel and be used by the furnace to work.
  • Oil furnace – You may have forgotten to refill the oil for the tank. If this is the case, simply fill it up.

4) Dirty Burner

Similar to the filter, the burner can be blocked by accumulated dust and dirt over time. As a result, it can’t use its fuel to produce and transfer heat to incoming air.

Though the fan can still blow, only an undesirable cool breeze or slightly warm air can come out from the air ducts.

To fix it, you can consult the manual and follow the steps in cleaning the dirty burner. But, of course, to ensure safety and efficiency, we highly recommend getting a professional to do it for you.

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