Can You Replace A Heat Exchanger In A Furnace? Vital Guide


The cost depends on your current furnace’s age and condition. It might be cheaper to replace the whole furnace than one part. Check if there are any warranty options available before repairs or replacement.

Can You Replace A Heat Exchanger In A Furnace

Can a heat exchanger be replaced?

Replacing a heat exchanger in your furnace is possible and sometimes necessary. It transfers heat from the combustion gasses to the air inside your home.

Wear and tear can cause cracks in it, which could release carbon monoxide and put you and your loved ones at risk.

Signs of a cracked heat exchanger

As a heating professional, I have come across various furnace issues, and one of the most serious problems is a cracked heat exchanger. 

Here are some indications that may signify the presence of a damaged heat exchanger in your furnace.

Carbon monoxide release

Carbon monoxide is a dangerous, odorless, and colorless gas. It can cause headaches, dizziness, nausea, or even death at high levels. 

CO detectors will alert you if there’s carbon monoxide in your home, which could result from a cracked heat exchanger.

This gas can be released from a cracked heat exchanger, making it a serious issue that needs to be addressed immediately.

Another possibility is flue gas leaking through cracks in the walls of the heat exchanger, mixing with air in the house.

The smell of gas or soot

A cracked heat exchanger may release combustion gasses which can create a smell. The odor is almost similar to a gas leak.

You may smell gas or soot in your house if you have a cracked heat exchanger. Unburned gas is released, which can pollute your home. If you smell gas, turn off your furnace right away and call an HVAC technician.

For example, 

Visible cracks, rust, or discoloration on the outside of the unit. You may also have poor air quality and high energy bills. Fixing these issues quickly is important to prevent further damage, and to protect your health.

Cold spots in the home

A cracked heat exchanger may not distribute heat evenly and can create cold spots in your home.

There was a story on 20/20 about how some people experienced carbon monoxide poisoning because of cracked heat exchangers in their furnaces. 

The hazardous CO gas had seeped into their homes through vents. So, be aware of signs of cracked heat exchangers if your cold spots don’t go away after using these techniques.

Burner flame color

A damaged heat exchanger may cause a problem with the burner flame, which may appear yellow or flicker frequently.

  • The color of burner flames can tell you a lot about your heat exchanger. 
  • Blue with a slight yellow tip is ideal. 
  • But, if the flame is all yellow or orange, it may mean incomplete combustion. This could be caused by too little air intake, clogged burners, or dirty filters. 
  • A flickering red-yellow flame might suggest a gas flow problem

Check out the table below for more flame color info.

Flame ColorPossible Cause
BlueWorking well
YellowIncomplete combustion
OrangeIncomplete combustion/dirty burners
RedGas flow problems

Age of the furnace

Time passes and our home furnaces age – the HVAC industry recommends replacing them every 15-20 years. If yours is around this age, you should think of replacing it soon.

A cracked heat exchanger is a sign that your furnace is getting old. This component is essential, and a breach can lead to dangerous things like carbon monoxide leaks or fires.

An aging furnace not only brings safety risks but also affects indoor air quality. 

Dust and combustion remain accumulate inside the vents, making the air unhealthy. This can cause respiratory issues and allergies.

Manufacturers have been making products with such accuracy for a long time, since ancient times when people used fireplaces to stay warm. 

Factors to consider before exchanging heater

When deciding whether to replace a heat exchanger in a furnace, there are several factors to consider. 

Age of current furnace

Evaluating the age of your furnace is critical. If it’s nearing the end of its expected lifespan, it’s wiser to replace than repair.

Look into the efficiency of your current furnace. Newer models use energy efficiently, resulting in lower heating bills. Upgrading can pay for itself.

Ongoing maintenance is an important factor too. Older furnaces need more frequent repairs, while newer ones come with warranties.

Consider the energy source. Switching to a gas or electric system could reduce costs and protect the environment.

Corrosion and damage to other components

Evaluating options requires considering potential corrosion and its effect on other parts. 

Corrosion might be caused by environmental factors or exposure to harsh substances, which can weaken materials and affect performance. This could damage related components and create a domino effect of issues.

To avoid this, we must assess the materials used in production and the working environment. For instance, welding chromium alloys may raise resistance to corrosion. 

Cost comparison of heat exchangers for a furnace

Making wise choices is vital. Cost comparison can help you stay financially secure. 

Here are a few tips to consider when comparing costs:

  • Think about the lifetime of a product or service; some may be cheaper right away, but others may save money in the long run.
  • Look at tangible and intangible factors together, such as vehicle cost, insurance rates, maintenance fees and fuel costs when analyzing a car.
  • A comparative table may help make the evaluation process easier. Prices may differ depending on location and are only approximate.
Product/ServiceInitial CostAdditional Costs over Time 

The energy efficiency of a new system

It’s important to consider energy efficiency when you’re looking to buy a new system. 

Here’s what to keep in mind:

Energy Star RatingA rating given by the US government to electronics that use less energy.
Power Usage Effectiveness (PUE)A metric to measure how energy is used in data centers.
Cooling Efficiency Ratio (CER)The ratio of cooling capacity to electrical power input for air conditioning.

Warranty coverage

When buying something, warranty coverage is important. It can save you from unexpected costs if something goes wrong.

What to do if you suspect a cracked heat exchanger?

As a professional HVAC technician, it is important to know what to do if you suspect a damaged or cracked heat exchanger in a furnace. 

Here’s what you can do:

Turn off the furnace

If you suspect a cracked heat exchanger, turn off your furnace immediately and do not use it until it’s been inspected by a professional technician.

Call a professional technician

A professional will schedule an appointment to perform an inspection and diagnosis of the furnace, determine if there is a cracked heat exchanger, and recommend the best course of action.

Consider repair or replacement options

If the heat exchanger is damaged, consider a repair or replacement job based on the technician’s recommendation and factor in costs, warranties, and safety. 

The technician might suggest a replacement rather than a repair if the furnace is already old, has a poor efficiency rating, or overall is not effective at heating the space.

Opt for a second opinion

If you’re unsure about the technician’s recommendation or the given repair cost, a second opinion can help you make an informed decision.

Call for a professional appointment

Be safe than sorry. Even small furnace issues can cause big problems if left untreated. Have regular maintenance and check up on any worries.

A faulty heat exchanger can be dangerous, especially if you live in a cold climate. Carbon monoxide can leak. So, call an HVAC technician straight away.

Technician inspection

Suspecting a cracked heat exchanger can be a daunting task for homeowners. Technician inspection is key to make sure your heating system is safe and functioning properly. 

The technician will visually check the heat exchanger for any cracks or separations. Specialized equipment may be used to detect carbon monoxide leaks. 

If a cracked heat exchanger is confirmed, immediate replacement is a must to avoid risks. Seek an expert opinion from a reliable HVAC company to decide what’s best for your situation.

Options for repair or replacement

As a professional in the HVAC industry, it is important to understand the options available for repairing or replacing a heat exchanger in a furnace.

 Here are some key factors to consider:

  1. First, have a professional technician assess the situation and determine if the heat exchanger can be repaired or if a replacement is necessary.
  2. If the heat exchanger can be repaired, consider the cost and the age of the furnace. 
  3. Sometimes, it may be more cost-effective to replace the entire furnace if it is nearing the end of its lifespan.
  4. If a replacement is necessary, there are two main options: replace just the heat exchanger or replace the entire furnace. 
  5. While replacing just the heat exchanger may be more cost-effective in the short term, replacing the entire furnace may be a better long-term investment for energy efficiency and safety reasons.
  6. Consider the manufacturer’s warranty and any warranties or coverage for parts and labor..
  7. It is also important to think about the safety implications of a damaged heat exchanger.
  8. A cracked heat exchanger can release dangerous carbon monoxide into the home, so addressing the issue promptly is essential.

Repair job

Repairing is a great way to fix something broken. It’s usually cheaper than buying something new.

You can contact specialty stores to find experienced professionals to do the job. They can help prevent further damage

Cost of labor and parts

Labor and parts cost is essential to think about when repairing or replacing something. Working out expenditure in advance is wise to help make the best choice. 

Here’s a look at labor and parts costs you might face:


Warranty coverage

When it comes to warranty coverage, it’s important to know what is and isn’t covered and for how long. 

Here’s a breakdown of the options:

LaptopHardware defects, software issues, accidental damage protectionUp to 5 years, depending on the manufacturer and plan chosen
AppliancesParts and labor for mechanical and electrical failuresVary by make and model, typically ranging from 3-7 years or up to a certain mileage limit.
CarMechanical and electrical issues, some warranties may include roadside assistance as wellVary by make and model, typically range from 3-7 years or up to a certain mileage limit.


Costs, environment, longevity, reliability… Consider all the details. Don’t rush it! Research and explore. No regrets later.

Cost of a new furnace

A new furnace can cost lots of money, but it doesn’t always fix heating issues. It can, however, provide energy-efficient solutions with reduced emissions

Below is a table detailing the cost and life expectancies of different types of furnaces.

Furnace TypeAvg CostAvg Life (yrs)
Gas Furnace$2,500 – $7,50015-20
Oil Furnace$3,000 – $8,00015-25
Electric Furnace/Heat Pump System$2,500 – $6,500+10+

The efficiency of a new furnace

Today’s energy costs are on the rise, so the importance of an energy-efficient furnace can’t be overstated. 

  • New furnaces save energy and money, plus they produce fewer emissions – doing their bit for the environment.
  • High-end models come with advanced tech too. Things like variable speed motors, two-stage burners, and sealed combustion systems help reduce heat exchange losses. This keeps electric bills low and pollution down.
  • Plus, you can control furnaces remotely or automatically, thanks to programmable thermostats.

A better option for the home

Here are some factors to consider:

CostsCheaper initially, but may need more repairs over timeMore expensive, but may save money in the long run
EfficiencyNo big changes, just fixing what’s brokenBetter efficiency with newer models & features, lower energy bills
Aesthetics & appealNew models have better eco features, reducing the carbon footprintNew products look better, increase curb appeal and add to home value
Longevity & DurabilityMay break repeatedly, leading to more replacementsNew products last longer and are tougher, reducing recurrent costs
Eco-FriendlinessFixing appliances reduces carbon footprint vs throwing away partsNew models have better eco features, reducing carbon footprint


When it comes to heating systems, efficiency, and safety are key. Seek an HVAC pro, Repair or replace the heat exchanger that depends on age, warranties, and costs.