How Long Does a Furnace Last On Average?

Everything comes with an expiration date, especially your home’s appliances. Of course, when something is integral to the function of your home— not to mention expensive— it’s essential to know how much life you’ll get out of it and what you can do to extend that life.

For example, how long does a furnace last? And how can you keep it running properly until it’s time for a replacement? Does it require maintenance? How do you know whether it needs to be replaced or simply repaired?

We’ll answer all of these questions and more below.

How Does a Furnace Work?

Getting to know one of the most important appliances in your home is the key to understanding how to keep it running efficiently and understanding what it needs and when. Generally speaking, furnaces have four main parts:

• The thermostat, which governs the numerical temperature, signals the furnace to turn on
• The ignitor, which is what receives the signal from the thermostat and ignites the fuel source to generate the heat
• The heat exchanger, which absorbs the heat from the burner to heat the air that gets blown through the air ducts
• The blower motor, which is what sends or pushes the heated air through the ducts

To recap, your thermostat regulates your home’s temperature by telling your furnace when to ignite fuel to get the combustion chamber warmed up. This heats any air that has been captured in the return air duct, and the electric motor pushes the heated air through the ducts to warm your home evenly to the perfect temperature.

Ultimately, your furnace has a bunch of moving and non-moving parts that need to be maintained properly for longevity and efficiency.

How Long Does a Furnace Last?

It can be difficult to give a concise answer to the question of how long a furnace is supposed to last. While the average lifespan of a furnace is technically over 40 years, it’s actually very rare that a furnace would last that long.

For example, a gas furnace has a lifespan of 15-30 years. However, you’re more likely to get between 20 and 25 years with proper maintenance. Ultimately, there are a variety of factors that contribute to your furnace’s longevity, including its energy source.

The types of furnaces you’ll come across include:

• Natural gas furnaces
• Electric furnaces
• Oil furnaces

Compared to older gas furnaces, newer ones are highly efficient. Electric furnaces don’t require a combustion chamber as they use heated coils to warm the cold air that gets drawn into the appliance. Oil furnaces use reheatable oil which is stored in the tank to warm the circulating air, and are usually found in areas where gas furnaces are unavailable.

While it’s well-known that oil furnaces take up the most space and are the least efficient of the three types, that doesn’t mean they can’t outlast a gas or electric furnace. It all comes down to the following factors:

• The make and model of the furnace. Once again, the newer models made today are generally designed to be more efficient and longer-lasting.
• Its age. The year your furnace was made will tell you what type of parts it has and how efficient it is. If your furnace is already 15-20 years old, it’s likely that you’re up for a replacement soon.
• Its size. The bigger the furnace the more surface area and parts that will require maintenance.
• Its installation. How your furnace was initially installed can affect how long it lasts. Improper installation can cause a laundry list of issues and cause your furnace to fail before it reaches old age. According to Energy Star, more than half of all new HVAC systems are improperly installed. As a result, rated efficiency levels are reduced by as much as 30%!
• How well it’s maintained. Furnace maintenance is incredibly important and it’s recommended annually. This annual maintenance allows for a skilled HVAC technician to come and carefully examine your furnace, take it apart to clean it, and ensure that everything is in good working order. Maintenance also includes changing out the filter as recommended by the manufacturer.
• How the thermostat is used. If you live in a home that likes to play tug-o-war with the thermostat settings, you’re going to wear down the appliance sooner than later. This is because it takes a significant amount of energy to heat your home, and signaling the unit to ignite multiple times throughout each day is going to wear down the most important parts.
• Its location and ventilation situation. Furnaces need the appropriate amount of space to function and to ensure that they don’t overheat and become a fire hazard. You also want to make sure they’re kept somewhere with low moisture levels as moisture will cause the heater components to rust, leading to premature breakdowns.

Regardless of whether you’ve had your furnace installed recently or bought it with your home, the most important of the above factors — and the only one you really have control over — is the regular maintenance. Annual furnace tune-ups and changing the filter when it’s time are the key to keeping your furnace healthy and operating efficiently.

How Do I Know When it’s Time to Replace My Furnace Vs Repair it?

The decision to replace or repair your furnace isn’t always a straightforward one. Of course, you’ll always want to follow the recommendation of your HVAC tech, but in the meantime, here’s an overview of scenarios that call specifically for a replacement:

• Your furnace was installed over 15 years ago. If your furnace is showing obvious signs of wear or if a part has broken down completely and your furnace is over 15 years old, it’s better to cut your losses and replace it with a newer model. Otherwise, you’re looking at more repairs in the near future.
• The cost of the repair is more than half the replacement cost. This is an obvious one, but if you have to make a repair that’s going to cost more than 50% of what it would cost to replace the appliance, it’s time to buy a new one.
• Your energy bill has gone up for no apparent reason. Heating costs fluctuate, but it’s a predictable fluctuation. If you’re starting to see unusual spikes on your energy bill, it may be time for either a tune-up or a replacement. If you’ve kept up with your furnace’s regular maintenance, then it’s likely the internal parts are starting to break down and fail.
• Your furnace doesn’t seem as effective as it used to be. If you’re starting to notice that some rooms are warmer than others or that the air in your home feels a bit humid, it may mean that your furnace is losing its power due to worn-down parts. Of course, this may indicate the need for maintenance, but it’s also highly likely that if your furnace is older then it’s time for a replacement.
• Repairs are becoming more frequent. If your furnace is starting to need repairs more frequently — as in every few months — then it’s a sign that the unit is on its way out. Low airflow and water leaks are one thing, but issues like a damaged heat exchanger or control module will only end up costing you more money in the long run.

Essentially, the rule of thumb comes from the first point, which is that if your furnace is older than 15 years old, you’ll most likely need to replace it.

You’ll especially want to replace it if it’s older and you’re planning to sell your home within the next few years. Homebuyers are always looking for the best possible investment, and furnaces are an indispensable asset that can add to your home’s overall value.

How Can I Extend the Life of My Furnace?

Whether you’ve installed a brand new furnace or your existing one is still in its prime, you’ll want to do all you can to extend its life. Here’s what’s within your control:

• Annual maintenance
• Frequency of use
• Equipment quality
• Humidity levels in the home
• Clean filters

We cannot stress this enough — the annual maintenance of your furnace is absolutely vital to its lifespan. Annual maintenance includes tune-ups once per year as well as regular cleanings in the fall and spring. The filters should be changed monthly or as per the manufacturer’s schedule to ensure that the airflow isn’t restricted, which can lead to overheating and damaged components.

As for the equipment quality, this mostly applies to having a new unit installed. You’ll want to choose a high-quality appliance by working with your HVAC specialist to figure out which type will work best for your needs and home.

Time For a New Furnace?

The average furnace’s lifespan directly depends on its age and how well it has been maintained over the years. If you think it’s time to replace your furnace, we have plenty of suggestions and the right specialists for the job.

Visit us today and learn more about our affordable options, energy rebates, and HVAC services.