More than 64 million homes in the U.S. use natural gas to supply them with heat during cold weather, and most of these homes use a furnace for the job. It’s not surprise that gas furnaces remain the #1 option for winter comfort: they can deliver high levels of heat and deliver them fast—all without putting a huge drain on a household’s budget. But when serious furnace problems arise, knowing how to handle urgent furnace heating breakdowns can help keep your home safer until professionals arrive.
Using natural gas, however, brings with it a few cautions. Although gas furnaces are constructed to be as safe as possible, there are potential hazards they can run into. The most concerning one is the cracked heat exchanger. When this happens, can the problem be repaired? Or is it time for a new furnace installation altogether?
When Should Heating Repair Include Furnace Replacement?
Heating repair may not be enough when a furnace has a cracked heat exchanger. Homeowners should consider replacement when:
- The crack could allow carbon monoxide to enter the home’s air
- The furnace is older or near the end of its expected lifespan
- The repair costs more than half the price of a new furnace
- The replacement part is expensive or difficult to source
- A technician confirms the system is unsafe to operate
In most cases, replacing the furnace is the safer long-term option. A licensed HVAC technician can inspect the heat exchanger, explain the safety risk, and recommend the right heating repair or replacement option.
Why a Cracked Heat Exchanger Is a Serious Problem
The reason a crack in a heat exchanger is such a cause for concern—and reason to think about replacing a furnace—is because it creates a major health hazard. The heat exchanger is a metal container inside the furnace that collects hot combustion gas from the burners. The heat from the gas transfers to the metal walls, causing the exchanger to burn hot. Air from the blower moves around the exchanger and picks up the heat before it passes into the ventilation system. The leftover combustion exhaust in the exchanger is then sent out a flue to harmlessly escape to the outside.
But, if the exchanger has cracks in it, the toxic combustion gases (mostly carbon monoxide) can enter into the air that’s being blown into the rooms. This is a huge health concern.
Can a Cracked Heat Exchanger Be Repaired or Replaced?
The best way to repair a cracked heat exchanger is to remove it and put in a new one. This doesn’t require replacing other parts of the furnace. However, it’s an expensive repair. Often a repair that’s too expensive compared to having a new furnace put in. A good rule of thumb is that any costly furnace repair decision that would cost more than half the price of a new furnace installation is a poor investment. You’ll save more money in the long run with a new furnace.
Why Older Furnaces Develop Cracked Heat Exchangers
Something else to consider: a cracked heat exchanger is something that happens most often in a furnace that is 15 years old or more. The long reaction of combustion gas and metal leads to corrosion that weakens the exchanger and allows cracks to form. An expensive repair for a furnace that’s this old isn’t worth it. You should already be thinking about replacement options, since the furnace will soon rack up silent furnace repair warning signs while losing energy efficiency with each year. With a replacement, you’ll have a more efficient furnace that will remain repair-free (as well as worry-free) for years to come.
No matter if it turns out you need a furnace replacement or a smaller furnace repair in Plymouth, IN, we’re the trusted contractor to call. We’ll help you make the best decision for your family and your budget when it comes to heating.
Frequently Asked Questions
Question: Can a cracked furnace heat exchanger be repaired?
Answer: A cracked heat exchanger is usually addressed by replacing the heat exchanger itself, not patching the crack. However, this can be an expensive furnace repair. If the repair costs more than about half the price of a new furnace, replacement is often the smarter long-term choice.
Question: Why is a cracked heat exchanger dangerous?
Answer: A cracked heat exchanger can allow combustion gases, including carbon monoxide, to mix with the warm air moving through your home. Since carbon monoxide is a serious health hazard, this problem should never be ignored. A professional should inspect the furnace and explain whether repair or replacement is safest.
Question: What causes a furnace heat exchanger to crack?
Answer: Heat exchangers often crack because of age, corrosion, and years of repeated heating and cooling. The metal expands and contracts every time the furnace runs. Over time, especially in furnaces around 15 years old or older, that wear can weaken the exchanger and lead to cracks.
Question: Should I replace my furnace if the heat exchanger is cracked?
Answer: Furnace replacement is often worth considering when the heat exchanger is cracked, especially if the system is older or the repair is costly. A new furnace can offer better efficiency, fewer repair concerns, and safer operation. A technician can help compare repair costs against replacement value.
Question: How do I know if my furnace has a cracked heat exchanger?
Answer: A cracked heat exchanger is not always easy to confirm without professional testing. Warning signs may include unusual odors, soot, poor heating performance, or carbon monoxide detector alerts. Since the risk involves combustion gases, homeowners should shut the system down if unsafe symptoms appear and call a qualified furnace technician.
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