Furnaces play an important role in keeping you and your family warm in the winter season. In a matter of minutes, they provide us rapid comfort that we all need.

At some point, you will be probably wondering how long do furnaces last and when will I need to change mine? The answer to this question comes down to basically the “age” of your furnace and how well it has been maintained.

Most furnaces typically last around 20 to 25 years and it’s not uncommon to see 30-year-old furnaces as well.  If your furnace is in a safe and working condition, there is no reason to stop using it, unless you decide to get a more efficient unit.

Why not keep a furnace for 50 years? As time goes on, new technologies arise and that includes your furnace. Quality of furnaces only gets better and if you desire a newer model, no-one can blame you for that…

Before you decide to move on to the newer model, here are some questions to ask yourself:

1. What is the efficiency of my current furnace?
2. What is the age of my furnace?
3. How heavily it is used (in case you live in the northern area)?
4. Was my furnace properly sized for my home? In case you did not know, improperly sized furnaces have a shorter lifespan.
5. Is it damaged in any way? Any unrepairable damages?
6. How well it is maintained? Did you follow the suggested maintenance schedule?
7. When does my warranty expire?

If your furnace is still under warranty and maybe a little bit less efficient than newer models (assuming that you kept it in proper conditions and no damages are involved), it makes sense to keep your furnace at least until the warranty expires. If your furnace is really old and uses up more resources than you would like it to, maybe it’s time to start looking for a more efficient model.

The best thing about older furnaces is that they are “built to last” and their lifespan could go as long as 30-40 years with proper maintenance. On the flip side, they are less efficient and cost more to use.

Here are some hints to look for in an aging furnace that possibly needs a replacement:

1. Is your furnace unsafe?
2. Does your furnace have a cracked heat exchanger?
3. Would the costs of repair be greater than purchasing a brand new one?

Here are different timeframes for furnace “life-expectancy” and if it’s age gets closer to the first number, it’s a good time to consider an upgrade:

Another way to determine your furnace’s lifespan is to watch for warning signs. Number one warning sign that you will probably notice:

Honey, our electric bill has gone UP this winter!

This is how you can tell if your furnace is getting more inefficient. Also, if you notice that you keep on making more repairs on it than before, it is another warning sign that your system is falling apart, and replacement may be needed soon.

Other reasons for the premature permanent breakdown of your furnace may include:

1. Not maintained properly. If you know for a fact that you did not take good care of your furnace and did not change filters on time, you will probably need to replace it before the average timespan. The good part? It will start “letting you know” that there is a problem in advance by failing to work properly!
2. Improper installation. This could also cause a problem in the long run and may even void your warranty if your furnace was not installed by a licensed HVAC specialist. So, be careful with that one, and if your uncle was installing it, maybe it’s a good time to give it a professional checkup.

** Important note! ONLY the specialist will know how and where to place your furnace properly to have good ventilation and clearance.

And, of course, if your house is not being heated the way that it should be, this is another sign that your old furnace may need to be replaced. Now we will go into details of how long different types of furnaces last (gas, electric, and oil):

What is the average life expectancy of a gas furnace?

An average gas furnace can last about 15 to 20 years if maintained properly. Getting a maintenance visit from your local HVAC company every fall will keep the life expectancy of your furnace on the higher end.

Your maintenance company will check all the components of your gas furnace and make appropriate adjustments and lubrication. This also gives you a chance to find out in advance if anything unsafe is happening to your furnace.

Problems that are not taken care of in advance, will definitely shorten the lifespan of your furnace while putting your home and family in a possibly dangerous situation. It is also a good idea to change your filters once every one or three months to keep the furnace in top-notch condition.

How long do electric furnaces last?

The average lifespan of an electric furnace is 20-30 years. With fewer components to take care of and no carbon monoxide gases to dump outside, it is considered to be a very reliable heating system.

Electric furnaces are easier to maintain (no gas burner or combustion process taking place) and they require fewer repairs. What does this mean for you? The less human error involved the longer the lifespan.

Since electricity here is the primary source of heating its operation is more expensive if compared to the gas model. Electric furnaces are also 100% efficient.

Other types of mainly electrical heaters that you could use and that do not consume so much energy are:

1. The heat pump with an average lifespan of 15 years.
2. The solar heating systems (solar panels as electricity source) should last for about 20+ years.

How long do oil furnaces last?

When we think of an oil furnace, a picture of an old oil lamp may come up:

Well, jokes aside (maybe 😉), but oil furnaces have a good reputation and can last a whopping 25 years for you!

In reality, the oil furnace has nothing to do with old and outdated! It’s a quite technologically advanced machine that vaporizes the oil and it works in a way similar to the gas furnace.

The best part about this system is that does not produce carbon monoxide (unless it is damaged), which could be dangerous if it starts leaking inside. Oil furnaces will also require you to set up an outdoor storage tank to keep extra oil in, but electric bills will not be as high, as with electric variation.

A well-maintained oil furnace can last even longer than 25 years. Keep in mind that the older the furnace gets, the less efficient it becomes.

If your oil furnace is older than 15 years, it will have an efficiency of about 70%, and when it gets over the 20-year mark, the efficiency level drops to 60%. Do you want your old furnace to use more oil to produce less heat?

If you answered “NO” to that one, maybe it’s a good time to get professional advice on a replacement.

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Attention! This article is for informational purposes ONLY and is NOT a replacement for a professional advice! You will need to visit school's website for details and updates, as well as consult your local HVAC specialist for appropriate solution to your problem.

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