Inside Temperature of the Home Is 66 But the Furnace Won't Heat

Thermostat Setting

• The thermostat’s settings may be the cause of an unresponsive heater. Make sure the thermostat is set on “heat” rather than “air.” Also, the fan should be set to “on,” as opposed to “auto.” Bear in mind that, even if the temperature inside of your home is 66 degrees, the system will not generate heat if the thermostat is set to initiate at a lower temperature. Accordingly, ensure you review your thermostat's settings when investigating potential causes of your heater not producing heat.

Thermostat Malfunction

• Your furnace may not be responsive at 66 degrees because of a thermostat malfunction. If there has been a power outage or some other type of power interruption, the thermostat may be malfunctioning and will not signal the furnace to generate heat. If the thermostat has a reset button, pressing it should clear erroneous settings potentially causing a malfunction. If the thermostat does not have a reset button, turn the thermostat off, wait a few moments, then turn it on again. Some furnace models have service lights that, when illuminated, indicate a service technician is necessary to solve the improper functioning of a piece of equipment.

Fuel

• The furnace may not be heating because of a lack of fuel. If the furnace is oil- or propane-based, there must be an adequate amount of fuel level in the unit, or it will not start. If fuel was added recently, the furnace may need to be reset. On some models, you can press a red reset button located on the burner; on other units, you would reset the unit by turning the power off, then on again. With oil-based furnaces, you may need to prime the pump before it will continue working after a reset.

Pilot Light

• The furnace may not be heating because of an extinguished pilot light. If you have a gas furnace, the pilot light should remain on at all times. However, if the light has gone out, the furnace will not produce heat. Follow the manufacturer’s instructions for lighting the pilot.

Other Considerations

• The heat may not be coming on because the gas is not flowing to the furnace. Ensure the gas meter controlling the gas feed to your home has been turned on by the gas company; if not, contact the company. In addition, examine the furnace’s main shut-off valve – and any other applicable shut-off valves - to ensure they are open. Finally, ensure the furnace is plugged in.