A host of factors determine the lifespan of a furnace, which is why it’s hard to be precise about its lifespan. However, we need to address the question: how long do furnaces last? Typically, if a furnace is well-maintained, it lasts about 15 to 20 years

The goal of this post is to give you some insights into the life expectancy of your furnace. We will also discuss factors that affect the durability of a furnace. And finally, we’ll explain the telltale signs that it’s time to replace your heating system.

Lifespans of Different Types of Heating Systems

It is important to remember that there are different types of heating systems, and their lifespans vary considerably. Here are the common types of heating systems and their typical lifespans: 

  • Boilers: 20-30 years
  • Gas Furnaces: Typically 12-20 years
  • Ductless MiniSplits: 18-25 years
  • Heat Pumps: Up to 15 years
  • Electric Furnaces: 15 to 25 years
  • Active Solar Heating: 18 to 25 years

Factors That Affect the Lifespan of a Furnace

High-quality furnaces last longer than cheaper units, and that is why we should choose trusted brands. However, maintenance plays a vital role here. Taking care of a furnace is easier if you know what factors can shorten the lifespan of a furnace. Here are some of those factors:


If you constantly change the temperature in your house, your furnace will work harder to keep up. Frequent temperature changes can affect the lifespan of your furnace.

A better idea is to program your smart thermostat to monitor and control the temperature. With smart thermostats, you can change the settings of your furnace in an energy-efficient way.


The size of a furnace is an important thing to consider because lifespan and efficiency depend on the size. If a heating system is too small for your home or office, the unit will have to work harder, and as a result, it will wear down pretty quickly.

And if the furnace is too large, it will perform more cycles, resulting in quick wear and tear. Get the help of a heating technician when choosing a furnace for your home or office.


How long do furnaces last? To some extent, it depends on how you take care of your unit. For smooth operation, a furnace requires not only DIY care but also professional maintenance. A furnace user must know the basics of general upkeep. It is vital to replace the air filters every couple of months.

General upkeep is not enough. Annual furnace inspections and cleaning are vital to extending the longevity of your furnace and its components. There are many advantages of yearly inspections. For instance, you can fix minor issues before they turn into significant problems.

Signs That You Need a New Furnace

There are some clear indicators that a furnace is nearing its end. Now we are going to discuss them. If you notice most of these signs, consider replacing your furnace with a new one.

The unit is more than 15 years old

If your furnace is less than ten years old, the parts are still under warranty. So, how long do furnaces last? The short answer is at least ten years.

But a unit is unlikely to need a replacement if it is less than 15 years old. When it is more than 15 years old, signs of malfunction and deterioration will be noticeable.

Heating bills soaring

If you are paying abnormally high heating bills for months and years, it is probably because your furnace is nearing its end. Electric or gas bills can dramatically go up when the internal parts of your furnace wear out. If the unit is old with worn-out parts, replacing the furnace may be better than repairing it.

Frequent repairs

In the last couple of years of its lifespan, a furnace incurs frequent repairs. If you have repaired the furnace too many times in recent years, you should probably replace the unit with a new one. Here is another clue: you should get a new furnace if the cost of repairs is around 50% of the price of a new unit.

Many people keep getting their old furnaces repaired and ask: how long do furnaces last? One way to answer this question is: there is no such thing as the death of a furnace. It should last as long as you can afford frequent, expensive repairs. At a point, replacing the furnace is a better option than repairing it.

The furnace is making noises

If your furnace makes popping, rattling, or banging noises, it is probably time to get a new unit. Also, when the blower automatically turns on and off, the system may make strange sounds. In such a case, get in touch with a professional HVAC company.

The thermostat setting has to be constantly adjusted

When your room is too cold or too hot, you need to adjust the thermostat. However, changing the thermostat may not be accessible when there is an issue with it. You may have to adjust it constantly to keep the temperature comfortable. If this problem continues, your furnace will soon need a replacement.

Weird odours

When you turn the heat on, you may get a slight smell of natural gas, and that is normal. However, if the smell is constant, probably something is wrong with the unit.

The smell may be the result of a crack in the heat exchanger. In extreme cases, gas leaking can lead to carbon monoxide poisoning. If you are experiencing dizziness, headaches, and nausea, stop using the furnace and call a technician. The technician may recommend replacing the furnace.

How Long Do Furnaces Last – Final Thoughts

As we have explained, it depends on the furnace you are using, because all furnaces are not the same. With that said, regardless of the type of furnace, get ready for a replacement when the unit is more than 15 years old. The key is to look for signs that your unit is nearing its end.