How Long Does a Furnace Last?

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Many homeowners ask, "how long does a furnace last?" when they're experiencing problems or trying to determine why they don't have heat! Let's face it, this is a common question when your furnace begins to fail or it's getting on in years. But in reality, how long your furnace lasts depends on many factors, including the care and maintenance you give it through the years.

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Furnaces, like most other home appliances, require regular maintenance and service to achieve the longest possible service life. Still there are other factors to consider, such as efficiency, performance, and the heating and cooling needs of your home. This article will help you not only answer the question of how long a furnace lasts, but also help you get the most out of yours.

Average Life Expectancy of a Gas Furnace

The furnace is a critical part of the HVAC system in your home, and even if you plan on replacing your heater soon, it's helpful to understand how it works. Your furnace burns fuel, typically gas, in order to heat the air which is then circulated through your home with a blower.

When the furnace is damaged, it may have trouble efficiently heating your home, or it may become unsafe to use and emit harmful amounts of hazardous carbon monoxide. There are also other factors to consider when determining the service life of your furnace, including performance, service, and maintenance.

The owner's manual for your furnace can provide some helpful clues and suggestions for when your unit will need to be replaced. In the manual, you may also find more information about the warranties that might still be active and information about potential replacement parts.

If you've lost your manual, you most likely can find one on the Internet. Many manufacturers have them available to download on their website.

Heating and Cooling Performance Over Time

Think of your furnace as the command center with the sole job to keep your house at the correct temperature. If your house is too hot, the air conditioner kicks in and blows cool air to lower the temperature; too cool, and the heater delivers hot air.

Your furnace's number one job is to keep you comfortable. But how does it know what to do? It uses a component called a thermostat to register the temperature within the home.

When the temperature drops above or below the set temperature, the thermostat delivers a message to the furnace, which then delivers, with the use of a blower, the appropriate hot or cold air. In order for your home to maintain efficient climate control, both the thermostat and blower need to be operational.

As a Furnace Ages

For the best heating and cooling efficiency, you'll want to make sure your furnace is receiving proper care. This means regular service and maintenance. Annual maintenance can help keep your furnace performing at it's best, and it may even extend it's service life.

With regular use, a furnace will suffer normal wear and tear, and buying a new unit will eventually be necessary. A gas furnace's efficiency will decline over time, especially if its 30-years old!

Homeowners can perform some furnace maintenance themselves; however, it is essential to consider whether this voids your warranty. If your furnace needs repair, it's often best to call in a professional that can assess performance and provide proper service.

If you have an older furnace, it's probably time to begin thinking about purchasing a new one. A gas furnace will start with relatively good performance, but over time the efficiency will begin to decline. A new furnace will almost always offer better efficiency and lower utility bills.

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Annual Service and Maintenance for Longevity

So, how long does a furnace last if it receives regular service and maintenance? The exact service life of your furnace is unknown, but service and maintenance play a significant role in extending its life.

Older furnaces can suffer from broken parts that make them unsafe to run in your home, which often means dangerous amounts of carbon monoxide in the air you breathe.

Possibly the least expensive and most important thing you can do to keep your furnace running efficiently is to change your filter on a regular basis. But there are other tasks that homeowners should do as well. 

Such as performing annual maintenance by completing furnace tune-ups and keeping the furnace and surrounding areas clean and clear of objects.

There shouldn't be anything placed within three feet of your furnace, and this includes items in storage, whether they are flammable or not.

The fan, pilot light, gas valve, and burners should be inspected each year. These systems will need to be cleaned and checked for cracks or other damage by a trained HVAC professional who can ensure your unit is operating safely and efficiently.

Other components that need inspecting include the heat exchanger, thermocouple, and the electrical and gas connection points. Over time it's not unusual for any of these parts to fail, and gas and electrical connections can become loose.

During a tune-up, your furnace will also have all of it's moving parts lubricated to help extend their useful life and prevent unnecessary wear. The repair professional will also conduct several different tests to assess the overall performance of the system.

The question: "How long does a furnace last?" can often be more accurately answered after a full tune-up and system test, since the technician will be able to speak directly to the performance and condition of your unit.

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How Long Does a Furnace Last?

On average, a gas furnace will last between 15 to 30 years, and in rare cases, some can last as long as 40. A propane furnace will last between 15 to 20 years, and an electric furnace between 20 to 30. Of course, regular maintenance and service play a large role in longevity. 

There's a difference between new and older models when it comes to longevity, and most modern furnaces will outlast earlier models. 

Modern furnaces also come with added safety features, which let you know when they need repairs or attention. Many new furnaces also feature a digital thermostat that allows the homeowner more control over the functions of the furnace. This level of control may also extend the life of your unit and enable you to enjoy the efficiency offered by a newer model.

When your furnace reaches the end of its useful life, there are some telltale signs. First, you may begin to see an uptick in the cost of your energy bills, despite the weather being comparable to previous years. You may also notice that parts of your home are unevenly heated, and that your furnace cycles on and off frequently.

The frequent cycling may be annoying after awhile, but air quality issues are often a bigger concern. Older furnaces often have trouble regulating the humidity, which can cause parts of the furnace to rust quickly. The rust particles, along with dust, frequently find their way into your home as they travel with the incoming warm air.

Routine Repairs and Service Matter

Your furnace works hard to ensure that your home receives adequate heating in the colder months, so it's safe to say it'll regularly need some cleaning and maintenance. Here's few things you can do to extend the service life of your furnace:

  • Visually Inspect Exterior - The first step is to clean around your furnace so you'll not only have sufficient space to work, but you'll also be able to check for visible debris or damage.
  • Clean Inside - Turn your furnace off and allow it to completely cool. Then clean the inside by vacuuming it out. The accumulated dust should be wiped away. A damp towel can be used to clean the blower's fan blades. If you're uncomfortable working inside your furnace, you can skip this step and allow a professional to do the cleaning for you.
  • Schedule a Furnace Service Call - This is a great time to call a professional to service your furnace. They'll be able to confirm that there's adequate movement of air flow through the system and replace any worn parts. If parts and repairs are needed ask if they come with a warranty. Even if they don't, in most cases, having the work done will extend the service life of your furnace. Prices for repairs vary, but they almost always are less than the cost of buying a new furnace.

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Efficiency and Safety Changes Over Time

The make and model of your current furnace is a vital factor to consider when estimating the service life of your unit. As a general rule, newer furnaces have a longer average service life than older units.

Frequently, homeowners think that older models out last new ones, but in reality, furnaces continue to become safer and more efficient when it comes to heating your home. This means, that you can enjoy many more years of service, especially if you schedule an annual maintenance tune-up.

If you're a DIY'er, you may be tempted to save a couple of dollars and do the annual inspection yourself. Your owners manual will most likely give you a good outline to follow. If you choose to go this route, we highly recommend hiring a professional at least every few years.

Repairman assessing furnace

Time for a New Furnace

So how long does a furnace last before you should consider replacing it with a new one? Truthfully there are far too many factors to consider for an exact number. But once you've decided it's time to upgrade, you'll have plenty of great furnaces to choose between. 

The cost of a furnace ranges between 2,000 to 10,000 dollars, and the price largely depends on the size of the unit and it's level of efficiency. 

There are a number of excellent well-known and respected brands available which produce high-quality furnaces. Lennox, Carrier and Trane all have positive and established reputations within the industry.

Performance Considerations and Tips

Getting the longest possible service life from your furnace requires more than buying a top-of-the-line unit. These four factors can help you get the most out of your investment:

  • Furnace is sized correctly for your home.
  • Professional installation.
  • Ideal thermostat settings.
  • Annual maintenance completed by a professional.

An HVAC professional can help you determine the correct size furnace for your home. They'll look at the square footage of your residence and provide you with a recommendation for additional necessities. 

It's not uncommon that one of the recommendations is to add a humidifier or dehumidifer. These auxiliary units help control moisture levels which can damage furnace parts and cause premature rusting.

We highly recommend having an insured HVAC professional complete the entire installation process of your furnace, AC, and any other features such as humidifiers. Proper installation is vital and determines the overall service life expectancy for your furnace.

As we stated above, it's essential to keep up with routine maintenance, such as annual tune-ups and inspections, as well as regularly changing the filter. A trained HVAC technician can provide further tips and suggestions for extending the service life for your specific unit.

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