How Long Does a Furnace Last?

Published 3/11/2025

A well-maintained furnace typically lasts around 15 to 20 years on average. This lifespan can vary depending on several key factors. Quality manufacturing and installation by a professional furnace replacement company like Mr. Duct will set up your new furnace to last longer. Diligent furnace maintenance, like annual tune-ups and filter changes, helps your furnace reach the upper end of its lifespan. On the other hand, climate and usage play a role. In colder regions such as the Chicagoland suburbs, furnaces run more often and may need to be replaced in 15 years, whereas in milder climates, they might last longer. The bottom line is that with proper care and moderate use, your furnace should give you two decades of service before you need to plan for furnace replacement services.

Factors That Reduce Your Furnace’s Lifespan

Even a good furnace can fail prematurely if certain factors come into play. Key issues that can shorten the life of your furnace include:

• Lack of regular maintenance - Skipping annual furnace maintenance visits and neglecting tasks like changing filters can lead to dirt buildup and added stress on components, this can significantly reduce the lifespan. Learn what's included in furnace maintenance services here. 
• Improper maintenance or DIY fixes - Attempting repairs or maintenance without proper expertise can inadvertently damage your furnace. Poorly executed fixes (or using the wrong parts) may resolve symptoms temporarily but often create bigger problems that shorten the unit’s life.
• Poor installation or sizing - A bad installation job can set your furnace up for failure. If the unit is not installed correctly – or is the wrong size for your home – it may cycle improperly and experience more wear and tear. Always use a qualified NADCA-certified furnace replacement company like Mr. Duct.
• Overuse and heavy workload - Furnaces that run almost constantly during long, harsh winters, or are frequently set to a high heat setting, can experience more strain. The harder a furnace works, the faster its parts wear out.
• Poor air quality - Dust, debris, or pollutants in your home’s air can clog filters and coat internal furnace components. This compromises airflow and can cause the furnace to overheat or work harder to push air. Consistently dirty filters and ducts can lead to early breakdown.

The Dangers of Using an Old Furnace

Running a furnace past its prime can introduce serious risks to your home and family. As furnaces age, they become less safe and less reliable. In fact, an aging furnace can go from unreliable and inefficient to dangerous. Here are some of the issues that might come up when you hold on to an old furnace for too long:

• Carbon monoxide leaks - This is the most serious hazard with an old furnace. Over the years, the heat exchanger can rust or crack – especially once the furnace is over 15 years old. A cracked heat exchanger may leak carbon monoxide (CO) into your home. CO is colorless and odorless, and CO poisoning can cause illness or fatality.
• Inefficiency and high energy bills - Older furnaces become much less efficient. Most furnaces over 15 years old operate at only around 70–80% efficiency at best. This means they waste 20–30% of the fuel, driving up your heating bills.
• Frequent breakdowns and repairs - Wear and tear on an old furnace can lead to repeated breakdowns. You might find that every winter there’s a new problem. Older units are more likely to need frequent furnace repair calls, which can get costly and inconvenient.
• Inconsistent or insufficient heating - Another danger of an old furnace is simply that it won’t keep you comfortable. Aging furnaces often struggle to distribute heat evenly, leading to cold spots in your house. They can also short-cycle or have trouble blowing enough warm air.

Rather than face safety hazards or high costs from an old unit, it’s better to contact a professional furnace replacement company like Mr. Duct once your system starts deteriorating. Check out our furnace safety tips to learn more.

Common Signs Your Furnace Needs Replacing

How do you know when your furnace is nearing the end of its life? Look for these warning signs:

• Strange noises - Loud or unusual sounds, such as banging or rattling, can signal a failing blower motor, heat exchanger, or other major components.
• Rising energy costs - If your heating bills have been rising without a change in usage, an aging, inefficient furnace is the likely cause.
• Uneven or insufficient heating - An older furnace may fail to distribute heat evenly throughout your home, leaving cold spots or never quite hitting the thermostat setting.
• Frequent repair calls - If you need to call for furnace repair more than once or twice a season, your furnace may be approaching the end of its life.
• Visible damage or cracks - Rust, corrosion, or a cracked heat exchanger are serious signs of physical deterioration. Any visible damage should prompt an inspection and probably furnace replacement services.

When these symptoms appear, it’s time to evaluate your furnace’s future. In many cases, multiple issues together indicate that furnace replacement services are the smartest course of action.

When Should You Replace Your Furnace?

Deciding whether to keep repairing or invest in a new furnace depends on several factors. Consider the furnace’s age, the cost of potential repairs, and whether it is still performing adequately. Many homeowners begin considering a new furnace when their old one is around 15 years old. After 15 to 20 years, parts begin to fail, efficiency drops and safety concerns can arise. If a repair would cost 50% or more of the price of a new furnace, it’s generally better to replace the unit. Also, issues such as inconsistent heating, rising energy bills, and frequent breakdowns can mean a new furnace would be more cost-effective in the long run. Above all, safety matters most. If you see that heat exchanger is cracked or you get alarms from a carbon monoxide detector, seek furnace replacement services immediately.

Furnace Repair vs. Furnace Replacement

When facing a heating issue, decide if repairing the existing furnace or replacing it entirely is more practical. If your furnace is relatively new and the problem is minor, repairing it may be wise. However, older furnaces with serious or repeated issues usually make replacement the better long-term choice. The type of furnace another consideration. Learn more about one-stage and two-stage furnaces here. If repairs are costly or your furnace is beyond its lifespan, upgrading to a new, high-efficiency unit can save money, improve safety, and boost your home’s comfort.

Why Choose Mr. Duct’s Furnace Replacement Services?

Mr. Duct HVAC Services is an NADCA-certified company and an authorized Trane dealer, making us the ideal choice for expert furnace replacement services in the Chicagoland suburbs. Our team of experienced technicians specializes in furnace replacement and installation. We take pride in offering industry-leading Trane furnaces, known for their durability and high efficiency. By choosing Mr. Duct, you’ll receive expert guidance on furnace models, top-quality installation, and ongoing support to ensure your new furnace runs optimally for years to come.

We believe in honest service, transparent pricing, and professional workmanship on every job. We also offer air duct cleaning and thorough inspections to help maximize your furnace’s lifespan. When you invest in furnace replacement services with Mr. Duct, you’re investing in a safer, more comfortable home for your family. Schedule and appointment today and take advantage of Mr. Duct’s furnace installation coupon.