Some unreliable techs will tell you that your furnace heat exchanger has cracked—when it hasn’t—just to sell you a replacement furnace.
You see, heat exchangers are really expensive to replace. And if yours really is cracked, it usually means you’re better off replacing the entire furnace.
But that’s a big “if.”
To help you avoid paying for a new furnace when you don’t actually need one, we’ll go over:
The heat exchanger is the part of your furnace that actually heats the air that gets pushed into your home. It consists of a set of metal tubes or coils that loop repeatedly inside your air handler.
Where the heat exchanger is located inside a furnace
Under normal operation, the heat exchanger combusts fuel (i.e. gas, propane or oil) to create heat and expels the combustion fumes via the flue pipe.
So, what can go wrong?
Well, 2 main issues can cause a heat exchanger to crack:
Though it’s relatively rare, a crack in the heat exchanger can impact the performance (and safety) of your furnace. A cracked heat exchanger also means toxic gases burned off during combustion, like carbon monoxide (CO), can possibly escape into your home.
If left undetected, CO other toxic combustion gases can cause harmful symptoms like:
Because the heat exchanger is located inside your furnace’s air handler, where it’s hard to see, detecting a crack can be difficult.
Many techs will argue the best way to detect a crack in a heat exchanger, but the AHRI (Air-Conditioning, Heating, and Refrigeration Institute) recommends disassembling the furnace “until you can visually inspect all heat exchanger exterior surfaces.”
Basically, any crack that’s large enough to impact combustion will be visible to the naked eye.
The AHRI doesn’t recommend using water or smoking agents, as those methods will detect any combustion leakage (and a small amount of leakage is normal).
So, if your tech said you have a cracked heat exchanger, ask to see the crack. You should get a second opinion if…
One of our trusted techs will properly inspect your heat exchanger and let you know whether you really need to install a new furnace.
We take pride in our work—our techs won’t ever sell you anything you don’t need.