How Long Does A Furnace Last (And Why)?

Exact Answer: 15 To 30 Years

A furnace lasts for around 15 to 30 years. However, many factors can either reduce or increase the life expectancy of a furnace. If noted carefully, a furnace shows signs of needed repair and replacements, and if done all the repairings and replacements, a furnace can go as long as 40 years as well.

How Long Does A Furnace Last

How Long Does A Furnace Last?

However, some factors can decrease the life expectancy of a furnace. These factors can be improper sizing for the furnace, improper installation, lack of regular maintenance, and other such factors that can contribute to reducing the life expectancy of a furnace.

Talking about the first factor, that is, improper sizing of the furnace is an important factor that needs to be considered as a major contributor to the reduced life expectancy of a furnace. While installing the furnace, it is important to put under consideration that the furnace has proper and needed space. If the furnace was not provided with the proper space then there would be no escape to the steam built from it.

Moreover, it also affects the heating and air conditioning system as well. This not just reduces the life expectancy of the furnace, but also reduces its efficiency as well, resulting in higher maintenance expenditure and bills as well.

The next factor that contributes to the reduction in life expectancy of the furnace can be the improper installation of the furnace. If the furnace is not installed perfectly or most suitably, then it can also result in improper functioning of the furnace.

If the ductwork is poorly designed, sized, or not sealed properly then it will hinder the furnace performance and its reliability. Moreover, if the venting is not done properly for the furnace and fuel lines also are not applied properly then also it can affect the performance of the furnace. This factor also contributes to the reduced life expectancy of the furnace.

Conditions Of The FurnaceTime
Properly maintained and serviced20 to 30 years
Not properly maintained and not serviced15 to 17 years

Why Does A Furnace Last That Long?

If you have a furnace at your home, then it is important to know and understand that just like your car, electrical appliances, and other such instruments, your furnace needs time to time services and maintenance as well. If taken proper care of all these small things a furnace can easily work efficiently and effectively for about 20 to 30 years.

Just like other electric appliances, the furnace also needs to be regularly serviced and it needs regular maintenance as well. There are many home heating technicians which are professionally trained for servicing such appliances. It is important to ask for such professionals to repair or do regular servicing of your furnace from time to time after regular intervals of time.

Such technicians can fix minor or major faults in your furnace and even clean your furnace as well. If service is done regularly, then it can increase the life expectancy of your furnace by 5 to 15 years.

Moreover, regular cleaning of your furnace increases its life expectancy. It is important to keep the motors, filters, and heat exchanger of your furnace free from dirt, dust, and other such debris. The air filter of your furnace is quite a sensitive part of the furnace and thus it is really important to keep it clean. Therefore, regular cleaning of the air filter of the furnace is important to make it work effectively and for a longer duration of time.


If taken proper care of all these factors, your furnace will easily last for about 20 to 25 years. However, if you feel that the bills and your expenditure on your furnace are going higher and higher, there is uneven temperature all-around your house, there is the drastic increase in your electricity bills, or it is blowing cold air, poor air quality in your house or your furnace is making noises then it is probably time to replace your old furnace with a new one.



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Hi! I'm Nidhi.

Here at the EHL, it's all about delicious, easy recipes for casual entertaining. So come and join me at the beach, relax and enjoy the food.

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