Heat exchanger replacement cost

The heat exchanger is the metal chamber that keeps burner exhaust separate from the air going to your rooms. Replacing it is one of the most expensive furnace repairs. Published ranges differ a lot by source.

These figures are a few years old in two cases and measure slightly different things. Use them to judge whether a quote is in a normal range, and expect your own number to depend on the furnace model.

• The part. Heat exchangers are made for a specific furnace model. High-efficiency furnaces have a primary and a secondary heat exchanger, and either one can fail.
• Labor. The technician has to remove the burners, the blower and a good part of the cabinet to reach the exchanger, then rebuild and test everything. This is why labor weighs so heavily on this job.
• Testing. A proper job ends with a combustion test and a carbon monoxide check.

Warranty status changes the bill more than anything else. Heat exchangers often carry a longer parts warranty than the rest of the furnace. If yours is still covered, you pay for labor only. Have the model and serial number ready and ask the contractor to confirm coverage with the manufacturer.

With this repair, the question of replacement comes up almost every time. Carrier's guidance is to consider replacement when a system is more than 10 years old or when repair costs approach 50% of the value of a new unit. An out-of-warranty heat exchanger on an older furnace often meets both tests.

Repair makes more sense when the furnace is fairly new, the part is under warranty and the rest of the furnace is in good shape. Replacement makes more sense when the furnace is old, the part is not covered, or the crack was caused by a problem that will come back, such as years of overheating from poor airflow.

The repair or replace calculator walks through the same decision with your furnace's age and your quote.

You cannot confirm a cracked heat exchanger yourself. It sits behind sealed panels, and many cracks only open when the metal is hot. Because the diagnosis leads to a large bill, ask for evidence.

• Photos or camera footage of the crack, or combustion test readings that show the problem.
• The part number and written confirmation of warranty status.
• Labor, part and testing listed as separate lines.
• A side-by-side price for a new furnace, so you can compare.

A second opinion is reasonable before you commit to either path. Keep the furnace off while you wait. The page on a cracked heat exchanger covers the warning signs and the danger in more detail, and the HVAC cost guides list prices for other furnace repairs.