How long do furnaces last? Do you need to replace the furnace now?

Furnaces are HVAC heating units that usually last a very long time. How long do furnaces last?

Here’s the short answer:

furnaces can run 5 to 30 years, This is a fairly wide furnace lifetime range. majority of furnaces will run from anywhere 10 to 20 years, Most homeowners want their furnace to last 30 years and would hate it if they only had to replace the furnace after 5 years.

how long do furnaces last
Furnaces last an average of 10 to 20 years. If you have a 30 year old furnace, you might consider replacing it with a new unit.

Here’s one thing even more important than knowing how long a furnace should last:

Do you need to replace your furnace now?

If your furnace is 20 or even 30 years old, then you Consider replacing your furnace, Signs that your furnace needs replacing:

  • making furnace loud noises While running
  • temperature is not as stable As it once was. You may experience temperature fluctuations throughout your home.
  • Can you understand soot accumulation Near the furnace register.
  • high heat cost, or higher repair expenses, or both.
  • The flames of the furnace that were once blue are now changing yellow flames,
    How to Know If You Need to Replace a Furnace?
    A healthy furnace has clear blue flames. if you see yellow flamesOf course, this may be one of the most obvious reasons to replace the furnace.

Most homeowners will want to know how to make a furnace last as long as possible (up to 30 years). Even more important is to know the mistakes that many of us can make that can reduce the lifetime of the furnace by 5-10 years.

We’ve gathered valuable insight into how long a furnace lasts. That is, we will look at:

  • 4 Ways How To Growth Lifespan of the furnace. You will follow these maintenance, size and BLA recommendations to keep your furnace operating at 100% level for as long as possible.
  • 4 things that Shortage Lifespan of the furnace. If you don’t want your furnace to stop working 100% effectively after just 5 or 10 years, you should avoid making mistakes that, frankly speaking, many furnace owners are not fully aware of Is.

Let’s see how to extend the time of what is good for the furnace:

4 Ways How To Extend The Life Of A Furnace By 20-30 Years

What is the average life expectancy of a gas furnace? A gas furnace lasts about 15 years. If you can figure out how long a gas furnace will last, you can Save up to about $1,000 per year Reasons not to buy a new gas furnace.

The same is true for electric, diesel and oil furnaces. The longer you can keep the furnace running, the more value you can get from the initial furnace investment. Here are 4 ways to make sure a furnace will last longer than its average lifespan:

1. A furnace large enough for your home (minimize wear and tear)

The primary reason why furnaces do not last long is insufficient furnace size. This is true in both of these cases:

  • big furnace Produces more wear and tear.
  • very small furnace Produces more wear and tear.

How is it possible for furnaces to cause more wear and tear if they are too large or too small?

Too Large Furnaces Cause Not Lasting Longer small circle, A furnace that is too large will normally turn on and off very quickly. This is because a large furnace will heat a space faster, achieve its thermostat set temperature, and shut down quickly.

With a quick succession of these short cycles, a furnace undergoes 70% more wear and tear than necessary (the exact percentage depends on how large the furnace is). It also generates 70% more wear and tear. If a gas furnace normally lasts 15 years, an additional 70% wear and tear can reduce its lifespan to less than 9 years.

If you have a very small furnace the same lifetime is decreased. a small furnace is a big house stay long, These furnaces will do everything in their power to heat a home they are unable to heat, running at nearly 100% heating output at all times.

This can reduce the average life expectancy of a small furnace from 15 years to less than 10 years (depending on how small the furnace is).

There’s an obvious solution to the problem: Get the right size furnace for your home. You should consult with an HVAC specialist about how big of a furnace you need. To get an idea of ​​how big a furnace you need in the first place, you can use our furnace sizing calculator here (just input square footage, and you’ll get a BTU estimate).

An appropriately sized furnace can last at least 20 years.

2. Choose a Good Furnace Installer

How well the furnace is installed will affect how long the furnace will last. In many cases, we see a furnace installation just like any other installation; Install it and be done with it.

However, we often see inadequate furnace installation. This is one of the most common reasons why furnaces do not reach their average lifespan of 15 years.

What is the difference between a good and bad furnace installation?

We can divide it into 3 parts:

  1. Good/Bad Ductwork. Ductwork is an extremely important part of furnace installation. Properly designed ductwork will allow for uninterrupted air flow. Improper ductwork, on the other hand, will create pressure pockets. Airflow through these pressure pockets would require a furnace to work extra hard, adding unnecessary wear and tear, and reducing the running time of furnaces. You can read a little more about duct sizing here and see a duct airflow velocity calculator here.
    Ductwork Affects How Long Furnaces Last
    Sufficiently sized ductwork is critical to prolonging the lifespan of a furnace.
  2. Good/Bad drainage system installation. This is relevant only for high-efficiency gas furnaces. They have a second heat exchanger that squeezes out the extra 10-15% of the heat. A side effect of this is condensation, and that water has to be adequately removed from the furnace. As a result of poor furnace installation, you may notice water leaking into your furnace. This is not optimal and can damage your furnace, reducing the life expectancy of the furnace.
  3. Installation of good/bad fuel lines. If you have a diesel or gas furnace, you will need fuel lines that supply diesel, oil, or gas to the furnace. We often see mistakes made in the installation of fuel lines, which, of course, will cause the furnace to break down sooner than expected.

A good installation can add up to 5 years to your furnace. More importantly, a poor installation (especially the drainage system and fuel lines) is one of the most common reasons why a furnace may stop working after 5 or 10 years.

Solution: It makes sense to find a reputable HVAC company here with experienced furnace installers and a good track record.

3. Routine Maintenance (Many Overlooked)

Routine maintenance goes without saying, doesn’t it?

Well, while everyone knows that regular furnace maintenance is good for prolonging the lifespan of a furnace, not everyone is actually invested in regularly scheduling HVAC-certified maintenance.

The main culprits that reduce furnace times as a result of low maintenance are:

  • Dirt accumulation on the heat exchanger. If you don’t clean the dirt regularly, it will start to accumulate on your heat exchanger. If the heat exchanger, in turn, cannot transfer heat efficiently, the furnace will have to work harder to produce the required heating output. More wear and tear equals less age.
    Heat exchanger dirt buildup shortens furnace lifespan
    The accumulation of dirt on the copper furnace heat exchanger looks like this. You can imagine that the heat exchange here is not 100% efficient.
  • Dirty filter. Furnace filters need to be changed from time to time. You can see here how often you should change the air filter. Using dirty filters will restrict air flow, again pushing the furnace to work harder to achieve the set temperature, adding to wear and tear, and taking your furnace to a quick grave.
  • Unbalanced fan. Simple wear and tear, or accumulation of dirt can cause the fan to become unbalanced. This can damage the fan motor which will again reduce the life of the furnace.

You already know the solution here. It is very important to schedule regular annual furnace maintenance before each heating season (and sometimes even after the heating season).

4. Lower Thermostat Setting (68°K is Ideal)

Running any furnace at high operating output for a long period of time can dramatically shorten the life of the furnace.

A good way to reduce the load a furnace produces is to lower the temperature setting on our thermostat.

Now, the ideal low temperature would be 68°K in winter, However, everyone needs to make a compromise between comfort and heating output.

If you can lower the temperature on your thermostat by a degree or two, you’re actively working toward prolonging the years your furnace will operate adequately.

4 Things That Decrease How Long a Furnace Will Last

No one really likes to replace a furnace every 10 years. Still, if you’re not a little careful, you might have to prematurely throw out the old furnace and install a new one.

Here are 4 things that can lead to premature furnace failure:

  1. insufficient size. As we’ve talked about earlier, a furnace too large or too small will unnecessarily add extra wear and tear, which can significantly reduce how long a furnace can last.
  2. bad installation. The trio of bad ductwork, poor drainage, and bad fuel lines installation will seriously affect the life expectancy of your furnace.
  3. No maintenance. The furnace has to be maintained regularly to reach the expected lifespan of 15-20 years. Dirty filters, dirt buildup on the heat exchanger and fans can negatively affect the health of your furnace.
  4. High thermostat setting. The higher the thermostat setting, the more likely the furnace has to malfunction. For example, having a thermostat temperature of 75°K in winter will have a negative effect on the longevity of the furnace in most cases.


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