Allergies and AC filters

Should You Repair or Replace Your Furnace's Heat Exchanger?

A cracked heat exchanger can not only rob your home of heat, but it can also pose a serious health hazard as it leaks carbon monoxide and other combustion gases. If you've recently found out your furnace has a cracked heat exchanger, you may be grappling with the decision to repair or replace that component. If you want to know whether you should replace or repair your heat exchanger, you should take a look at the following.

Minor Cracks May Be Repairable

Most heat exchanger failures start out with microscopic cracks, which eventually expand with time and continued use. If these cracks are caught early enough, it may be possible for your HVAC contractor to seal the cracks through welding or the use of epoxy. Such repairs are usually intended for short-term use, as there could be more cracks or severe rust as the heat exchanger ages.

Major Cracks or Severe Rust Warrants Replacement

Over time, those relatively small cracks can grow into larger, more visible cracks that actually allow carbon monoxide and other combustion gases to leak out of the heat exchanger. In many cases, it may be impossible to properly seal these types of cracks without compromising the performance of the heat exchanger itself. When faced with this issue, it's usually best to replace the entire heat exchanger rather than attempt a repair.

In addition, corrosive condensate can also cause severe rust and corrosion to form throughout the heat exchanger surface. This can leave behind microscopic pinholes and other damage that is nearly impossible to weld or epoxy. In cases like these, a replacement is usually the only course of action available.

Weighing the Cost of Repairs vs. Replacement

It's usually cheaper to have the heat exchanger repaired rather than undergo a complete replacement, especially if the repairs needed are relatively minor. On the other hand, a complete replacement may be your only option when it comes to restoring your furnace's performance. Unfortunately, the replacement process can not only be lengthy, but also expensive given the average hourly rates offered by most contractors.

There's also the cost of replacing the heat exchanger versus the cost of replacing the entire furnace. In some cases, having the heat exchanger replaced could cost as much as purchasing and installing a brand-new furnace. If your furnace is more than 10 years old, then replacing the entire furnace may make more economic sense than simply replacing the heat exchanger. To learn more about your options, resources like can help.