How To Tell If You Need To Repair Or Replace Your Furnace?

Are you concerned about your furnace, and do you not know if it is time to change it or not? The furnace is an essential part of an HVAC system. If it is malfunctioning, it can affect the system’s overall efficiency, or worse, it can break down suddenly while you most need it.

But before a breakdown, there are always some signs that indicate something wrong with the furnace. Below you will find the main signs that your furnace needs to be repaired. However, if you are unsure if something is wrong with your system, read more.

What are the signs that you have to replace your furnace?

Every furnace will need to be repaired sooner or later. This doesn’t mean that it needs to be replaced. However, specific things will tell you that the moment to get a new furnace is very close or has arrived. 

Here are some of the main signs you need a new furnace:

1. Too many repairs

If the furnace needs constant attention and you have to call the repair man too many times, it is a sign that you should consider a new furnace. If you have to repair your furnace every year, or even two times a year, it can become expensive without getting the final result of a working furnace.

While it costs less to repair a furnace, it might be more convenient to get a new furnace if you add up many repairs over several months. To determine what you should do, calculate how much it costs for a new furnace and how much you spend on repairs. 

Age can be a significant factor at this point because if you have to repair your furnace often and it is already over 15 years old, then the decision should rest on getting a new one.

2. Consider the age of the furnace

The furnace’s age is one of the primary factors to consider when deciding if it is time to buy a new one. In general, most furnaces last between 15-20 years, with the exception of some furnaces that last up to 30 years. 

If your furnace reaches the 20 years mark, or even more, you know that its life cycle is toward the end. Even if the furnace has no apparent problems and doesn’t require repairs, you should still consider beginning to set aside money because of an imminent replacement. 

3. Increased energy bill 

Another clue that your furnace is getting old and that a new one will do a better job is the increased energy bills. With age or malfunctioning parts, a furnace is less efficient and will need to use more energy to perform its functions. 

With usage, the parts of a furnace get worn out, and the system will not manage to transform all the gas or fuel into heat. In general, a furnace will not transform 100% of the fuel in heat, but the percentage of the fuel converted decreases even further with wear and age. 

This situation is soon reflected in higher consumption and higher bills. In addition, if you are not raising the temperature or leaving your system turned on for more extended periods and the energy bill increases, then the furnace is not as efficient as it should be. 

4. Noises coming from the furnace

Strange and unusual noises coming from the furnace are not a good sign. If the noises are louder than usual or you hear rattles or hums, the furnace can have structural problems. 

While it is normal for a furnace to produce noises when it is turned on or running, it is not normal if the sounds you hear are different or more frequent. For example, if you hear a loud boom, the furnace can build up fuel and make a loud sound when it starts. 

If that happens, the heat exchanger can break, requiring expensive repairs. Here are some of the sounds you could hear and what is their possible meaning for them:

  • Shrieking sound: in general, a sound of metal scraping against another metal could signify that a system component is not where it should be or is loose. It could result in significant damage, and if so, you could consider replacing the furnace instead of a reparation.
  • Whining sound: it is another sign of a problem with the furnace. It is necessary to have a technician locate the source of the problem. 
  • Rumbling sound: a furnace can rumble when running, but if it is a continuous sound and becomes louder, it could signify a problem with the ignition system.

5. The furnace appearance

If your furnace gets rusty or if you see visible cracks, you might consider a replacement. It is usual for a furnace to show signs of usage after several years; however, when they become structural problems, it is not possible to remedy anymore, and a new furnace should be gotten to replace the old one.

Rust can form in places where the metal is exposed to the fuel. However, rust can make the furnace structure very weak over a long period, creating leaks and other problems. 

In addition, soot is usual in a furnace, but when it is too much, it signifies a higher production of carbon monoxide because of incomplete combustion. 

After inspection from a qualified technician, the furnace should be cleaned or consider getting a new and more efficient furnace. Moreover, if you see visible cracks, you need professional assistance to figure out how to remedy the situation.


A furnace has a very long life cycle. But, maybe you do not know the age of your furnace if you are not the one who installed it in your new house; however, toward the end of the furnace life, you can experience several issues. 

After a few calculations, you can figure out that getting a new furnace to be covered through winter is better. 

If you are unsure if your furnace still has something to give you or if it is time to get a new one, obtaining professional advice can help you make a proper decision. 

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