What is a Heat Exchanger and Why Should I Care?

Understanding a key component of your furnace

Furnace repairs are, for some people, like visiting the garage for a car engine repair.  The experts speak in a language that you don’t understand, talking about parts and components as if you’re a NATE Certified HVAC Technician. At best these talks are overwhelming and at worst, they are terribly confusing.  So if you are having furnace issues and your technician tells you your heat exchanger needs repair, here is some information to help you understand what is a heat exchanger and why you should care.

The heat exchanger is a major, and fundamental, component of a gas furnace and in some respect is similar to the engine of your car. It also houses combustion gases so it can be a threat to homeowners if something goes wrong. We recently asked HVAC expert, Keith Hill of Minnesota Air to help us out with the details and he tells us, the heat exchanger has two purposes:


The heat exchanger confines the flame and flue gases to the inside of the unit and separates them from the air stream (the air that blows into your home).


The heat exchanger also transfers the heat from the flame and combustion side of the furnace to the air stream to heat and warm your home.

When it needs repair, it is usually due to a crack or leak that has occurred in the heat exchanger.  Should you care if it has a crack or leak?  Yes, especially if you have an older furnace (15+ years) that makes carbon monoxide (CO).  Although unlikely, it’s possible that a leak or crack could release CO into your home.  With an older furnace that needs a heat exchange repair or replacement, it may be time to look into replacing the unit altogether due to the time and expense in the repair.

Heat exchangers have an average life expectancy of 20+ years. If the furnace is nearing this age, other components are also beginning to wear and consequently few heat exchangers are replaced because pulling a furnace apart and replacing the heat exchanger costs almost as much as replacing the whole furnace. In most cases, the entire furnace is replaced.

If you opt to replace your furnace with a newer, more efficient model, it will likely come with a lifetime warranty and you won’t really have to worry about that heat-exchanger any longer.

Regardless if you repair or replace your heat exchanger, you will want a trusted HVAC technician to patiently walk you through your furnace inspection and diagnosis.  And as always, only trust a certified technician with all your questions and repairs.

Minnesota furnace repair

For home maintenance and comfort tips, visit StayComfyMinnesota.com! Stay Comfy, Minnesota is your Minnesota resource for air conditioning repair, furnace repair and HVAC tips and advice.

About Ed Heil

Owner of StoryTeller Media & Communications an inbound marketing and digital PR agency in Bloomington, MN.
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