If your furnace is putting out no heat, here are some things to check before calling in a professional. Some of these might seem a little ridiculous, but youd be surprised how easy it is to overlook the most basic of problems. The first thing you should do is to make sure your air filter is not clogged. If it is not, or that does not solve the problem, then go through the following potential solutions.


  • Make sure the selector is set to heat.
  • Make sure the temperature is set at least three degrees above the current room temperature.
  • If you have an electric thermostat, make sure the batteries are charged and the display is showing.
  • If you have a forced air furnace and no heat, make sure the thermostat has a switch to control the furnace fan. Switch the fan to on and listen to make sure the fan comes on. If you cannot hear the fan, check a supply register to see if air is coming up. If the fan does not run, the furnace might not have power.

Electric Furnace with No Heat

If you have an electric furnace, it may have an emergency shut-off switch. If it does, make sure it is turned on. Usually, the emergency shut-off switch will look like a regular light switch and be located on the side of the furnace or close to it. This switch may have been accidentally turned off.

There are other heating systems that have emergency cut-off switches that automatically activate when a service panel or door is removed. The furnace door may have not been properly replaced after its filter was cleaned, and that could be why the furnace is not engaging and you have no heat. Make sure all access doors are correctly fitted and secured.

Make sure the breakers have not tripped and the fuses have not blown. If the fuse has blown, then make sure you replace it with the same size fuse. If the breaker keeps tripping or the fuses keep blowing out, call a qualified electrician to determine why the problem persists.

Oil/Gas Furnaces with No Heat

If the furnace is operating but there is no heat being produced, then try the following:

  • Make sure you have fuel. This sounds ridiculous, but we have made many service calls only to find out that the furnace had run out. If you check the fuel level and it is sufficient, you may need to reset the system by pushing the red button on the burner. Other systems reset by being turned off then back on.
  • If you have an oil-fueled system, you may need to prime the pump. You should call Approved Comfort to have a technician perform this procedure.
  • If you have a gas furnace, check to make sure the pilot light is lit. If not, follow your owners manual instructions in order to light it. If it will still not remain lit, call an Approved Comfort technician.

There could be other problems, such as a loose fan belt, tight blower motor, broken gas igniter or a bound gas inducer motor, that will require a technician. If you still have questions, please call Approved Comfort at (815) 219-7102!