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Should You Replace a 25-Year-Old Furnace?

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The heating system in your home is like an old friend. This trusty system has stuck with you through thick and thin, helping you weather the coldest of winters. Unfortunately, even the closest, most dependable of friends are no match for the stresses of time. Eventually, there will come a day when your furnace will need to be replaced.

If your heating system has just reached its 25th birthday, you may be wondering if the time for an upgrade is soon approaching. As a homeowner, it’s understandable if you aren’t familiar with when to replace furnaces. These HVAC systems are specifically designed to last a long time, so there’s a good chance you haven’t had to replace your furnace yet.

So, should you replace a 25-year-old furnace? We’ll answer this question and more below!

How Long Does a Furnace Last, on Average?

When it comes down to it, the average lifespan for a furnace is 15 to 25 years. Of course, the life expectancy of these heating systems can depend on various factors, such as the type of fuel they run on and whether or not you schedule regular maintenance. With all things considered, your furnace isn’t likely to see more than 30 years of life.

So, should you replace a 25-year-old furnace? When you ask HVAC professionals this question, you’re likely to receive an unwavering “yes.” If your furnace has been operating for more than 20 years, there’s a good chance the system has lost some of its efficiency. You’re also likely to encounter more issues with the heating system as it ages — such as costly repairs — that disrupt your comfort and waste precious time.

Furnace Age & Efficiency

Hopefully, you now understand that you should replace a 25-year-old furnace with a new, energy-efficient model. But why is efficiency so important?

As your furnace ages, it can experience regular wear and tear. This damage can make it difficult for your heating system to complete its job. As a result, the furnace will need to work twice as hard to warm your home. In the end, you can find yourself dealing with higher energy bills or hot and cold spots in your living spaces.

How efficient is a 20-year-old furnace? All-in-all, you can expect the heating system to be considerably less efficient than newer models. If you’re unsure when to replace furnaces, consider taking a look at your energy bills. If the cost doesn’t seem to equate with your heating system usage, then it might be time to schedule a heating replacement.

How Efficient Is a 20-Year-Old Furnace Compared to a New Unit?

Technological advancements have made newer furnaces much more energy-efficient. If your furnace is 20 years old, it’s likely operating with an Annual Fuel Utilization Efficiency (AFUE) rating significantly lower than modern models. This means a substantial portion of the energy is wasted, which is both economically and environmentally inefficient.

When it comes down to it, today’s furnaces are designed to be more energy-efficient, reducing your energy bills and minimizing your carbon footprint. If you’re pondering how efficient a 20-year-old furnace is, consider this: older furnaces often operate at efficiency levels below 70 percent, while new models can achieve efficiency ratings of 90 percent or higher.

Moreover, an old furnace might struggle to distribute heat evenly, leading to uncomfortable cold spots in your home. This inefficiency is a clear sign that your heating system needs attention. If your old furnace is gas-powered, the concerns go beyond efficiency; a cracked heat exchanger, a common issue in older furnaces, can lead to dangerous carbon monoxide leaks.

Signs Your Furnace Needs Replacing

As we’ve mentioned, knowing when to replace furnaces can be challenging for homeowners. Fortunately, there are a few warning signs you can look out for to help you determine whether or not it’s time for an upgrade.

Poor Heating

Is your furnace failing to keep up with your heating needs? Are you feeling cold spots throughout your home? These can be some of the most obvious signs that your furnace has reached the end of its useful life.

Frequent Repairs

Are you constantly calling a professional technician to repair your heating system? If so, it might be time for a furnace replacement in Fresno, CA. Repair costs can add up over time — especially if your furnace keeps breaking down and needing the assistance of an expert.

If you’re unsure whether to repair or replace your furnace, take a look at the system’s age and repair history. Suppose your unit is more than 15 years old and needs frequent furnace repairs. If this is the case for you, replacing the system can be the most cost-effective solution.

Strange Noises

It’s important to pay attention to any strange, loud noises your furnace might be making. This is especially true if you have a gas furnace. When a heating system makes unusual sounds, this is usually a clear indication that something is wrong.

If you have a gas furnace, a rattling sound can indicate that the heat exchangers are cracked. You’ll want to address this problem as soon as possible to prevent a serious problem, such as carbon monoxide leaking into your home. If your furnace is old, needs frequent repairs, and makes loud noises, a replacement could be the best option. You’ll want to talk to an HVAC technician to discuss your options.

When Repair Is an Option

Deciding whether to repair or replace your furnace can be challenging. Here are some considerations:

Age and Condition

If your furnace is nearing the 20-year mark, it’s crucial to assess its condition. Frequent repairs, a cracked heat exchanger, and poor indoor air quality are signs that your furnace might be on its last legs. However, if it’s well-maintained and hasn’t had many issues, a repair might suffice.


Consider the repair costs versus the price of a new furnace. If the cost of repairs approaches 50 percent of the cost of a new furnace, it’s usually more cost-effective to replace the entire furnace. Also, newer furnaces are more energy-efficient, which can save money on heating bills in the long run.

Safety Concerns

An old furnace, especially a gas furnace, can pose safety risks like carbon monoxide leaks. If there are concerns about safety, replacing the furnace becomes more than a matter of efficiency — it’s a matter of household safety.

The Benefits of Replacing Your Furnace Before an Emergency

Now that you know when you should replace a furnace, it’s time to start thinking about the best course of action for your current situation. Replacing your furnace before it fails completely offers several benefits. First, it allows you to avoid the inconvenience and discomfort of having no heat during a cold spell. Emergency furnace replacement can also be more expensive, as you might not have the time to shop around for the best deal on a new heating system.

Modern furnaces also offer improved safety features, such as better carbon monoxide detectors and systems designed to shut down automatically if a problem is detected. This reduces the risk of carbon monoxide poisoning, which can be a concern with older gas furnaces.

If you’re ready for a gas, electric, or oil furnace installation, turn to Lee’s Air, Plumbing & Heating. We can guide you through your options. Our experts also offer a wide range of other services, including furnace maintenance in Sacramento, to keep your heating system running when you need it most.

Making the Right Choice

Deciding whether to repair or replace your furnace is not always straightforward. Consider factors like the age of your furnace, its current efficiency, repair history, and safety concerns. When should you replace a furnace? If your furnace is over 20 years old, it might be time to consider a replacement, especially if you’re experiencing issues like poor air quality, frequent repairs, or high energy bills.

Contact Our Furnace Specialists for Your Replacement!

Should you replace a 25-year-old furnace? As you can see, the answer to this question is usually “yes.” If your heating system is getting old, there are also many signs you need a furnace to look out for. These red flags can help you make a decision that benefits your family in the long run.

Now that you know when to replace furnaces, turn to Lee’s Air, Plumbing & Heating! Our Visalia HVAC experts can help you find a new heating system that meets your needs and exceeds your expectations. Contact us today to schedule an appointment in Fresno, CA, or the surrounding area.

Thomas Howard

Written by Thomas Howard

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