Anatomy of a Gas Furnace


Have you ever wondered how your furnace works? Well, with the many different styles of furnace out there, it is impossible to make a catch-all post about all parts. Instead, we have taken a look at some of the more common furnace components and explained their functions.

Anatomy of a Gas Furnace

  • Flue Gas Vent – The flue is a plastic or metal vent that discharges all of the potentially dangerous by-products of your furnace outside your home. All of those dangerous carbon monoxide molecules are filtered out of the house by this vent, keeping you and your family safe. Most instances of carbon monoxide poisoning that happen in residential homes are a direct result of a cracked flue. Make sure it is checked regularly and that you have a carbon monoxide detector installed near your furnace as well as one on each floor.
  • Gas Valve – This is a safety mechanism inside your gas furnace that shuts off the gas flow if the pilot goes out.
  • Pilot light – The pilot light is the “spark of life” for your gas furnace. The pilot is a small gas flame that is used to light a larger burner, in this case, the gas burner that heats the air circulated through your furnace. Pilot lights are being phased out in some equipment to make way for more energy-efficient, electricity powered ignition systems.
  • Gas burner – this is your heat source.
  • Cold air return – this is where the circulated air from your home comes back into the furnace to be reheated and vented back into the house.
  • Circulating fan – the circulating fan has a big job! This is the fan that moves air from point A to point B and keeps the air circulating in your house. The air is pulled in through the air filter via the cold air return and pushed through the system by the circulating fan, where it is then sent back out into the home.
  • Air filter – The air filter helps to remove dust, dirt and other airborne particles from your house. Make sure to change the air filter regularly to ensure peak efficiency of your furnace. If the air filter isn’t changed regularly you end up circulating a lot of the nasty bits of stuff that have been removed from the air. As well, if the air filter is clogged, your furnace fans have to work harder to circulate air, putting a strain on the machinery.
  • Heat exchanger – This is where your air picks up its heat. As the air passes the heat exchanger, the energy is passed into the air, heating it up. This air is then circulated back into your home.
  • Ductwork (for heated air) – And the air is back in your homes, warming you up!

There you have it; you now know more about how your furnace works to keep you warm on those chilly winter nights.

If you have any HVAC related questions, please contact us through our website, via Twitter or on our Facebook page.

Image: indyedge / 123RF Stock Photo

Posted in: Heating, Home maintenance tips - Tagged with: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

« Previous
Natural Resources Canada – Part 6 of the EnerGuide Series
Next »
Trane Furnaces keep on Chugging