How Long is an Average Furnace Life?

How Long is an Average Furnace Life?
If you own a furnace, you've probably wondered how much longer it will last, as a failure could cause a major disruption to your comfort and lifestyle. This guide shares some tips for increasing the life span of your furnace as well as some common signs you may need a new unit. We'll also talk about what to look for when shopping for a new furnace.

How Long Do Furnaces Usually Last?

The average furnace lasts between 15 and 30 years. Some experts recommend replacing your furnace after 15 years, but most agree that 30 years is the maximum furnace life span. This is because, once your furnace has passed the 15-year mark, any repairs you make could cost you more than what you could possibly save by buying a new, more efficient furnace. Furnace technology is constantly improving, so it's important to be familiar with all the options available when deciding whether to repair or replace your old unit. Furnace life span is affected by multiple things.

How Do Furnaces Age?

High-quality systems obviously last longer than low-quality systems, but many other factors influence how quickly your furnace ages, including:
  • Quality of installation: If a furnace is installed improperly, this could lead to unnecessary strain on the unit, shortening its life span.
  • Frequency of use: If you use your system more and live in a colder climate, this will put more stress on your furnace, especially if the unit is older and less efficient.
  • Temperature management: How well you manage your comfort will also affect the life span of your furnace. If you keep your house cooler in the winter, especially when no one is home, your systems will not be as strained. Using set temperatures, preferably for a minimum of 8 hours at a time, will also be easier on your furnace than frequently changing your settings throughout the day.
  • Appropriateness of size: Furnaces that are properly sized for their homes will last longer. If it's too big or small, it will cycle more than it needs to, which will shorten its life span.

When should you replace your furnace?

When to Replace a Furnace

While furnaces generally last at least 15 years, it's impossible to know the life span of an individual unit in advance. However, several signs can indicate a unit is nearing the end of its life, including:

Rising Energy Costs

Your furnace consumes more energy than most other appliances in your home, which means that its efficiency is important. Once winter begins, take a good look at your energy bills. If you notice you're paying significantly more than in previous years — despite rates staying the same — you will want to consider an upgrade. While repairing your unit may boost its efficiency somewhat, newer models are more efficient and tend to perform at their peak efficiency for longer, so upgrading to a new furnace will likely provide you with more savings in the long run.

Uneven Heating

As your furnace ages, it will become less and less able to distribute heat throughout the rooms and floors of your house. If you notice sudden changes in the temperatures between different rooms in your house, this means it's time to start looking for an upgrade.

Frequent Repairs

If you're frequently having your furnace serviced and are spending hundreds or thousands for repairs, it's time to look for a new unit.

Loud Noises

Another telltale sign of a failing furnace is loud and unusual noises, which include:
  • Popping: Popping is the result of temperature fluctuations in your furnace. This noise is coming from components affected by this temperature change.
  • Screeching: This sound most likely means that the blower motor has been damaged, although it can also suggest a damaged belt or pulley.
  • Humming: A low humming noise is normal and is caused by the blower motor in operation. However, if the noise becomes noticeably loud, it's time to look into buying a new furnace.
  • Rattling: If you're hearing a rattling sound, this may mean loose equipment or ducts. Speak with an HVAC professional about whether this warrants a replacement.
  • Booming: If you hear a booming sound, this may be a sign of a serious gas emission problem. This sound is generally caused by a short delay during the ignition process. If this is accompanied by a lingering gas smell, this is a clear sign that your furnace will need to be replaced.
  • Clicking: Clicking noises often mean your igniter or flame sensor needs repairs. Fortunately, this noise is not uncommon and can often be repaired during a standard furnace repair.

The House Isn't Warm Enough

If your heat is on but you're still feeling cold indoors, this is one of the most obvious signs that something is wrong. It's important to note that this issue could be caused by other things, such as a malfunctioning or broken thermostat, but if there are no alternative explanations, don't push your system into overdrive — have it professionally inspected instead to see if replacing your unit is the best course of action.

Frequent Cycling

Most modern furnaces shouldn't need to cycle on and off to maintain a comfortable temperature. If you've noticed your furnace cycling frequently, don't ignore this sign — it could indicate a failing unit.

Air Quality Issues

As a unit nears the end of its life, it may no longer be able to reduce humidity or prevent excessive dust from entering the air you breathe in your home. In summary, there are many problems that lead to a furnace failure, whether it be temporary or for good. If the cost of repairing it is prohibitive — or if replacing it is the only option — remember that, although furnaces aren't cheap, newer models are more efficient than ever before. This means that upgrading to a new model will save you in energy costs, which will help you recoup your costs over time. Your furnace should be professionally installed.

How to Extend the Your Furnace Life Span

One of the most effective things you can do to extend your furnace's life span is to have it professionally installed. Improper installation is one of the biggest issues associated with gas furnaces in the United States. Poor installation can easily compromise the performance of high-quality furnaces. Namely, it will significantly decrease the efficiency of your unit, which affects how it heats up and stabilizes temperatures. This will, in turn, will lead to higher utility bills. Homeowners who choose to install their furnaces themselves often end up with the following issues:
  • Ductwork with leaks and cracks
  • Poorly designed drainage systems
  • Improperly sized furnaces
  • Poorly designed air distribution systems
  • Rusting due to installation in a humid area
  • Improperly designed exhaust systems
For these reasons, you must take your furnace installation seriously and have it professionally installed. Other ways to prolong furnace life span include:

Add a Programmable Thermostat

Programmable thermostats allow homeowners to control the temperature of their homes automatically, decreasing the amount of time that their furnaces run needlessly. This saves them money and time.

Seal Leaks Around the Home

If there are leaks in your air ducts, some of the heated air will escape and not be delivered to your living space, meaning that the furnace will have to work harder to heat your home to the desired temperature. Seal leaks around ductwork, doors and windows to increase your furnace's efficiency and life span.

Reduce Humidity

If a furnace is in a humid environment, it will rust more quickly, which will shorten its life span. The best way to avoid this problem is by not installing it in a humid environment, although if your existing system is in a humid place, you can reduce the humidity by running a dehumidifier.

Clean Filters Regularly

Regularly cleaning the filters on your furnace will help to prevent dirt and dust from damaging your furnace. It also prevents these particles from circulating around in your home, thereby reducing the number of household allergens. We recommend that you check your filters at least once a month when your furnace is being used heavily. This is one of the simplest furnace maintenance tasks and anyone can do it. The filter is usually located between the blower and the return air duct, and removing it is generally easy, although you might need a screwdriver to pry open the door. After you've cleaned or replaced the filter, make sure you insert the filter in the right direction, which will be indicated on the filter itself.

Schedule Regular Maintenance

Just as with any other important appliance in your home, proper maintenance is critical for your furnace. To make sure your unit is operating with the highest efficiency possible and prevent costly repairs, you should have your furnace inspected by a professional at least once a year. Ideally, this should be at the end of the winter season. If the HVAC system also has AC, both systems should be inspected at the same time.

What to Look for in a Replacement Furnace

When shopping for a furnace replacement, it's important to learn about all the available options. Many characteristics, including the size, type and efficiency, all affect how much it will cost to run during the coldest time of year. One of the most important considerations is efficiency, and we recommend you buy the most efficient furnace your budget allows. When it comes to furnaces, efficiency means how much of the fuel that goes into your furnace becomes heat for your home. This is measured in terms of a percentage and is referred to as the Annual Fuel Utilization Efficiency (AFUE). To meet regulations, furnaces must have at least 80% AFUE. However, some models have efficiencies as high as 95%, meaning that only 5% of the energy consumed by the unit escapes through the flue. Higher efficiency means you use less fuel to warm your home, which can translate to lower utility bills. Other factors to keep in mind when looking for a new furnace include:

Fuel Source

Furnaces typically have one of three fuel sources — natural gas, oil or electricity. We'll cover a few important characteristics of each type:
  • Gas: Gas furnaces, which consume natural gas, are the most economical furnace type for heating your house when outside temperatures are below freezing. If you already have a gas furnace, replace it with another gas furnace. Upgrading to a new gas furnace from another fuel source can be expensive upfront but save you money in the long term.
  • Oil: Oil and propane furnaces are also reliable and powerful heat sources, although they take up more space. They're also dirtier than natural gas furnaces and are often more costly, although this depends on the price of oil. However, oil and propane are usually used in regions without gas lines and are particularly common in older houses.
  • Electric: Electricity is another alternative to natural gas when it comes to heating your home. However, electric furnaces can be very expensive to operate. An electric furnace has to create original heat out of electricity — a process that can significantly increase your utility bills. A more economical option is an electric heat pump, which transfers heat from one air stream to another, thereby consuming less electricity. These systems also serve as air conditioners in the summertime. Depending on your situation, an electric heat pump may meet all of your cooling and heating demands.

Type of System

There are two fundamental layouts of heating and cooling systems — split and packaged:
  • Split: Split systems are probably what you imagine when you think of heating and AC systems. They consist of a furnace, a coil that rests over the furnace, and a condensing unit.
  • Packaged: Packaged systems provide the same heating and cooling services that split systems do, but unlike split systems, the cooling and heating components are all housed in a single, outdoor unit. This option is designed for homes that don't have basements, attics and crawl spaces. It's also worth considering if you have a split system but would like to free up some space in your home.

Blower Speed

A furnace can have one of two blower types — fixed-speed and variable speed. Variable speed blowers do just as their name suggests. They vary how fast the blower operates as it pushes air through the ducts in your home, meaning the temperature in your home can be consistent and the unit will run more quietly. Single-speed blowers, which are more traditional, are either on or off. With these blowers, it's more difficult to achieve a consistent temperature in the house, and it's also noisier, as the speed at which the blower runs is usually higher than is needed to maintain a set temperature.


The length of the warranty that comes with the system says a lot about its durability and life span, so try to pick a model with the longest warranty possible.

Installation Quality

Even if you purchase the most efficient heating system out there, if it is poorly installed, it will likely not operate at its indicated efficiency and experience a variety of performance problems, which will be costly for you in the long run. Some homeowners are tempted to install their heating units themselves to save money. This usually leads to problems, as heating systems are more complicated than most people think.

Need a New Furnace?

If your furnace is exhibiting any of these signs, you may need a new furnace. We'll help with that! Visit our webpage to start your search, or give us a call at 270-575-9595!
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