Gas Furnace Safety

If you have a gas furnace, it is important to know that it may produce some carbon monoxide that is released outside your home through the furnace’s vent. Carbon Monoxide is an odorless and colorless gas that can cause flu-like symptoms, disorientation, confusion, and even death. 

A clean, efficiently burning gas furnace produces very small amounts of carbon monoxide, while a dirty, inefficiently burning one can produce deadly amounts. Newer gas furnaces are equipped with many features that shut the furnace off when a problem is detected, but older furnaces may not have these safety devices.


To avoid this hazard, AHRI offers the following guidance:

  • Have your furnace cleaned and checked every year by a qualified heating contractor. This should be done twice a year prior to the onset of the heating and cooling seasons. Your contractor should check your furnace for small cracks in the combustion chamber. These cracks may not be visible to the naked eye. It is through these cracks that Carbon Monoxide can leak into your home. Your contractor also will lubricate the motors and bearings. 
  • Install a carbon monoxide (CO) alarm in your home. 
  • Change your furnace filter regularly. The filter is usually found inside the front cover of the furnace. It may have its own access door on the front of the furnace. A clean filter will help your furnace burn more efficiently, and will help keep dust from being circulated through your home. 
  • Keep the area around your furnace clean and unobstructed. 
  • Keep the burner area of your furnace clean. 
  • Never operate the furnace without the front-panel door properly in place. Doing so may create the risk of CO poisoning. Most forced-air furnaces have a safety switch that prevents furnace operation when the door or panel to the blower compartment is not in place. Some older forced-air furnaces do not have a safety switch and can be operated with the filter compartment door/panel off or not properly in place. 
  • Do not have anything combustible such as paint thinners and gasoline near your furnace. 
  • Do not close off more than 20 percent of the registers in your house. This can cause high resistance and unnecessary heat build-up in the furnace. In addition, vacuum dust, lint and animal hair from all registers.