With the quick changes in temperature this season, condensation on your furnace may result in a costly, potentially health threatening risk – a cracked heat exchanger. The heart of your furnace, the heat exchanger is responsible for holding the flame and removing harmful byproducts of combustion, including carbon monoxide, water vapor and caustic condensation. Without proper functionality, the heat exchanger could pose an unnecessary threat to your home and your family.

Let’s Look At a Few Causes Of a Cracked Heat Exchanger To Protect Your Home From Potential Dangers:

Normal wear and tear

Heat exchangers are made of metal that expands and contracts each time your furnace turns on and off. Over time, this stress creates cracks. However, if your furnace is well maintained throughout its lifetime, you can significantly prolong the amount of time it takes for those cracks to develop.

Airflow restriction

The most common cause of an overheated heat exchanger is a dirty air filter. A clogged air filter restricts airflow through the furnace, overheating the heat exchanger and eventually resulting in stress cracks. Closed or blocked air registers and furniture blocking return vents can contribute to slow airflow and your system working overtime.

Improper combustion of gases

If your gas furnace is operating with an incomplete combustion process, your burners will have to run hotter and longer. This excess heat puts more stress on your heat exchanger, which leads to cracking.


A problem most commonly associated with an oversized furnace is condensation. In a correctly sized furnace, condensation builds up inside your heat exchanger when your furnace first turns on. This condensation eventually evaporates after a few minutes of use. In an oversized furnace, however, that condensation doesn’t have enough time to evaporate. This condensation can eventually rust out the walls of your heat exchanger or freeze and cause cracks.

Secondary heat exchangers

High efficiency furnaces typically have two heat exchangers. The secondary heat exchanger usually contains more condensation than the primary, and is the first spot you should inspect for a crack or fracture.

Undersized furnace

An undersized furnace is just as detrimental to your home as an oversized. If your furnace is too small, it will have airflow problems and frequently overheat. Overheating will cause your heat exchanger to crack at a much quicker rate.

When is it time to repair?

If your heat exchanger has cracked and your furnace is less than ten years old, Wyckoff Heating & Cooling suggests a furnace inspection. Our certified technicians have a variety of testing procedures at their disposal to analyze combustion, airflow and visible signs of a heat exchanger crack. Though the life expectancy of a heat exchanger is approximately twenty years, our certified professionals can help you make the right choice for your home.

Don’t miss your opportunity to safeguard your furnace before the long winter months ahead. At Wyckoff, our home professionals care about your comfort and safety. Contact us today for more information on your HVAC inspection.