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How Much Does it Cost to Replace a Furnace Heat Exchanger in Phoenix?

November 17, 2020

Updated June 2024

If you’ve recently been told that you need to replace your heat exchanger, you’re probably wondering how much it’s going to cost.

Unfortunately, replacing a heat exchanger is one of the most expensive furnace repairs, typically costing Phoenix homeowners anywhere from $1,500 to $5,500.

We’s an expensive repair. So, before we dive into any details, there are two pieces of advice we want to provide:

  1. If you’ve been told that you have a cracked heat exchanger, get a second opinion. This is a very expensive repair, and you’ll want to ensure that the original diagnosis was correct.
  2. If you do have a cracked heat exchanger, you need to replace it ASAP (or at least before you turn your furnace on again). A cracked heat exchanger can release carbon monoxide into your home, which can be fatal.

Because replacing a cracked heat exchanger is a very expensive repair, we’re sure you have questions, like:

  • How do I know if I have a cracked heat exchanger?
  • What causes a heat exchanger to crack?
  • Why does it cost so much to replace my heat exchanger?
  • Should I replace my heat exchanger or just replace my entire furnace?

Below, we’ll answer these questions so you can get a better understanding of whether or not you need to replace your heat exchanger and why it costs so much.

Need a second opinion or your heat exchanger replaced NOW? We’d be happy to help. You can schedule an appointment with us or learn more about the furnace repair services we offer.

How do I know if I have a cracked heat exchanger?

To verify that your heat exchanger is actually cracked, there must be cracks visible to the naked eye.

Sometimes, techs will tell you that the cracks are too small for the naked eye to see, but trust us, if the crack is enough to consider replacing your furnace, it should be visible.

Unfortunately, convincing homeowners that they need a new heat exchanger is a common scam among sketchy HVAC companies, and it’s one we don’t want you to fall for. If your heat exchanger is cracked enough that it needs to be replaced, there should be visible cracks that an HVAC tech can point out to you.

Outside of any visual cracks, some signs that you may a cracked heat exchanger include:

  • Carbon monoxide alarm going off- Carbon monoxide is a byproduct of your furnace’s combustion process, so if your carbon monoxide alarm goes off and they determine it’s coming from your furnace, it's probably a cracked heat exchanger. Note: If your carbon monoxide alarm goes off, leave your home and reach out to your local fire department immediately. Carbon monoxide exposure can be fatal.
  • Soot buildup- If you notice soot buildup on the outside of your furnace, it’s usually due to a crack in your heat exchanger. Soot is also a byproduct of combustion and can leak out of your heat changer through any cracks.

What causes a heat exchanger to crack?

If you do have a cracked heat exchanger, you’re probably wondering why.

The simple answer: Heat exchangers crack due to overheating. When your furnace overheats, the exchanger’s coils expand. When your furnace cools down, they retract again. This expanding and retracting can cause the coils to bend and eventually crack.

Overheating can happen for a variety of reasons, but a few of the most common include:

  • A dirty air filter that has blocked the airflow to the furnace
  • An oversized furnace that is cycling on and off too often
  • Lack of maintenance, which can cause certain parts to work harder than they should and can overheat your furnace

To prevent a cracked heat exchanger in the future, it’s important that you:

  • Install a correctly-sized furnace
  • Keep up on regularly replacing the air filter (every 1-3 months)
  • Invest in annual maintenance with a professional

Why does it cost so much to replace my heat exchanger?

There are two key reasons that your heat exchanger is so expensive to replace:

  1. The heat exchanger itself is an expensive part
  2. It takes a long time to replace a heat exchanger

The “parts” cost

A heat exchanger is an expensive part because it’s the piece of your furnace that heats your home’s air.

Your heat exchanger is a collection of heated coils that has cold air blown over it, turning the air from cold to warm. Because your heat exchanger is such an integral (and complex) part of your system, it’s extremely expensive to replace.

The “labor” cost

In addition to the cost of the actual part, heat exchangers take a long time to replace (about 8-10 hours on average). That’s quite a lot of time for an HVAC professional to spend, which makes the labor cost of installing your exchanger more expensive than other repairs.

How you can reduce the cost

Even though replacing a heat exchanger can be expensive, it could be significantly less expensive if your parts warranty is still valid. A parts warranty is provided by the manufacturer of your furnace and typically lasts up to 10 years.

If your parts warranty is valid, it may cover the cost of the heat exchanger itself, leaving you responsible for only the cost of labor.

To check the validity of your parts warranty, you can usually visit the manufacturer’s website and enter the model and serial number of your furnace.

However, keep in mind that there are certain actions that can invalidate your warranty. For example, to maintain a valid parts warranty, you can’t have repaired your furnace with any off-brand parts since it was installed. You’ll also have had to have registered your furnace with the manufacturer (usually within 60-90 days).

Should I replace my heat exchanger or just replace my entire furnace?

Faced with the cost of replacing a heat exchanger, you’re probably wondering whether you should just replace your entire furnace instead. It depends on the age of your furnace.

On average, furnaces last about 12-15 years. So, if your furnace is over the age of 10, our advice would be to just replace the entire furnace rather than paying to replace an expensive part and then turning around and replacing the furnace in just a few years.

However, if your furnace is younger than 10, it’s probably more cost-effective to just replace your heat exchanger rather than replacing your entire system.

If your furnace is older and you want a second opinion, we’d be happy to help. Our honest techs will happily take a look at your furnace and provide you with recommendations on whether or not it’s in your best interest to replace your entire furnace or just your heat exchanger.

Need to replace your heat exchanger or furnace? Call the best techs in Phoenix: Patrick Riley

Need your heat exchanger or entire furnace replaced by a team of pros you can trust? Contact Patrick Riley. All of our techs are trained to repair and replace any make or model of furnace, so regardless of whether you need your heat exchanger replaced or you need an entirely new furnace, we’ve got you covered.

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By Ty Lindsay

Ty Lindsay is the Director of Field Operations at Patrick Riley | Isley’s and a 15-year veteran of the plumbing and HVAC trades. In 2010, Ty earned his Journeyman’s plumbing license. He became a Master Plumber five years later and earned his Journeyman HVAC technician’s license that same year. Ty’s breadth of knowledge in plumbing and HVAC includes both residential and commercial work. He’s been a loyal member of the Patrick Riley | Isley’s team since 2016.