Understanding Your Furnace and How to Use it Safely

Posted by: Joe Schwartz

Published: November 15, 2017

After a warm autumn, the temperatures are officially starting to drop and, for many, that means firing up the furnace for the first time months.  While the furnace’s main job in your home or business may be obvious, understanding the intricacies of how it works can help you warm your space safely and cost-efficiently.



It all starts with your thermostat, which serves as the temperature sensor in your space. If the temperature dips below the number you designated, the thermostat sends a low-voltage signal to your furnace. This signal tells the gas valve to open, filling the burners with natural gas. Simultaneously, the furnace’s pilot light sparks inside the combustion chamber. These combined actions cause air to warm-up in the furnace’s heat exchanger, where the air will stay until it reaches the desired temperature. It is then pushed through your ducts into your home or business. The combustion gases that are a by-product of the burned fuel are then vented safely outside via a flue.


  • Have your furnace inspected annually by a certified technician to check for cracks in the combustion chamber which lead to carbon monoxide leaks. Find a technician here.
  • Install carbon monoxide detectors to alert of any leak. Remember, Carbon Monoxide is odorless and colorless, virtually undetectable by humans.
  • Keep any combustible materials a safe distance from your furnace (Propane tanks, paint thinners, etc.)
  • Keep at least 80% of your air vents open and all of them clean and free of debris. If too many vents are closed or blocked, it can cause an unnecessary heat build-up in the furnace.


  • Natural gas is a much cheaper utility than electric.
  • Wiring problems on an electric furnace can cause fires.




Think of an electric furnace like a combination of a gas furnace and a hair dryer. Much like its gas counterpart, electric furnaces start with the thermostat sending a signal to get things going. When triggered, the furnace will suck air in through a cold-air return and filter it of debris and allergens. The air then passes through electric heating elements that condition it to the desired temperature. The air is then pushed through ducts to the home or business.


  • Clean and change your furnace filter every 3 to 4 months to maximize the efficiency of the furnace and to keep dirt and allergens from your living space.
  • Disconnect the power supply before performing any maintenance on the furnace.
  • Have a certified technician inspect your unit to make sure all wiring is done correctly and there is no risk of a fire.


  • No threat of carbon monoxide leaks.
  • No gas valves that can falter and allow gas leaks and buildup, which could spark an explosion.


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Joe Schwartz

Joe is a Marketing Specialist for Doyle Security responsible for online content management.

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