We’ve written before about the importance of having your furnace’s heat exchanger regularly checked by a professional. This is a part of our routine preventive maintenance program, the Ultimate Service Agreement, and it’s a vital inspection to make sure that a furnace operates as safely as possible. What our technicians look for when they examine a heat exchanger is signs of cracks along it or corrosion that can lead to those cracks. A cracked heat exchanger can allow toxic combustion gases to escape into the airflow moving into the rooms around a house—a dangerous situation!
Furnace owners often feel nervous when they learn their furnace may pose a safety risk. This leads to the question whether they should have the furnace repaired—which means replacing the heat exchanger—or instead have a new gas furnace installed.
Does a Cracked Heat Exchanger Mean You Need a New Furnace?
The damage to a furnace’s heat exchanger that can lead to cracks usually occurs because the heating system is near the end of its service life, probably older than 15 years and maybe 20. Corrosion is the most common of the aging effects that can trigger cracks in a heat exchanger. The reaction of combustion gases with the metal in the heat exchanger leads to corrosion over time (faster if there is poor ventilation).
We don’t recommend keeping a gas furnace that’s more than 20 years old, since it can mean numerous problems along with the safety risk. If a technician discovers a cracked heat exchanger in a furnace that’s older than 15 years, it’s much more cost-effective to have the furnace replaced rather than just the heat exchanger. A furnace this old doesn’t have many more years of quality service left to it, and you’ll need to replace it soon anyway. If you install a higher efficiency furnace, it will start paying back the replacement cost with better energy performance.
Should You Replace a Cracked Heat Exchanger or the Entire Furnace?
The cost of putting in a new heat exchanger varies depending on the furnace. If you have a younger furnace that might have another decade of service in it, you’ll have to weigh the cost of the heat exchanger replacement against getting a new gas furnace. In general, if the heat exchanger replacement is more than half the cost of a replacement furnace, the new furnace is a better option. Let your HVAC technicians help you make the best choice. If the cracked heat exchanger is a sign of larger problems with a newer furnace (unfortunately a common situation if amateurs installed it), then a replacement is both the more effective solution and the safer one.
No matter if it’s time for a heater replacement or a targeted heater repair in Fresno, CA, we’re the experienced HVAC contractor to call in the Central Valley. Remember, only licensed professionals should work on a natural gas furnace. We’ll not only ensure you have the best furnace for your winter heat, but that you and your family will be safe. When it comes to gas furnaces, safety is always our top priority!
Frequently Asked Questions
Question: Is it safe to run a furnace with a cracked heat exchanger?
Answer: No. A cracked heat exchanger can allow combustion gases, including carbon monoxide, to enter the air circulating through your home. Because this creates a potential safety hazard, the furnace should be inspected by a licensed HVAC professional. The technician can confirm the damage and determine the appropriate repair or replacement option.
Question: Does a cracked heat exchanger mean I need a new furnace?
Answer: Not necessarily, but furnace replacement often makes sense when the system is older. Furnaces over 15 years old may have limited useful life remaining, making an expensive heat exchanger replacement less practical. For a younger furnace, compare the cost of replacing the heat exchanger with the cost of installing a new furnace.
Question: Can a cracked furnace heat exchanger be repaired?
Answer: A damaged heat exchanger is generally addressed by replacing the heat exchanger rather than repairing the crack itself. The cost varies depending on the furnace. If heat exchanger replacement costs more than about half the price of a new furnace, replacing the entire furnace may be the more practical option.
Question: What causes a furnace heat exchanger to crack?
Answer: Heat exchangers can develop cracks as the furnace ages, particularly because of corrosion. Combustion gases react with the metal over time, gradually contributing to deterioration. Poor ventilation can accelerate corrosion. A cracked heat exchanger in a newer furnace may also indicate larger installation or system problems that should be professionally evaluated.
Question: How do I decide between replacing the heat exchanger and replacing the furnace?
Answer: Consider the furnace’s age, remaining service life, condition, and the cost of replacing the heat exchanger. If the furnace is more than 15 years old or the heat exchanger replacement approaches half the cost of a new furnace, complete furnace replacement may make greater financial sense.
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