Why Should I Replace My Furnace When It Works Fine?

Maybe your existing furnace is fine. It might be 5, 10, even 15 years old or more, and it doesn’t give you an ounce of trouble.

If so, then this article might not be for you. After all, replacing any piece of HVAC equipment is a personal decision. Usually.

But I want you to think about this: Appliances tend to break at unfortunate times. The refrigerator dies right before a dinner party. The dryer calls it quits when you have three loads of laundry left to do, and you don’t have time to get to a laundromat.

And if your furnace conks out in the middle of an ice storm, all of a sudden you have to worry about pipes bursting.

There are telltale signs that your furnace gives when its time nears an end; some are obvious, and some are subtle.

And sometimes even an HVAC professional with dozens of years of experience can’t predict how long it will last. Five more years? Ten? A well-maintained furnace can last at least 15 to 20 years, but completing annual maintenance and being diligent with repairs can extend its life even longer. It’s also possible that a furnace will conk out just after the warranty expires.

So here’s the question you might ask yourself: Why replace my old furnace when it works fine?

Reliable Heating and Air

We take the reliability of our heating and cooling systems for granted. It’s not uncommon when I hear a homeowner say, “I replaced that furnace three years ago,” and I check it out and discover that it’s actually eight years old. And it hasn’t had any maintenance on it except for the occasional change of filters.

But it continues to run and gives them good service. It’s a testament to the furnace’s reliability.

It’s so reliable, in fact, that we tend to pay attention to it only when something’s wrong.

What if it breaks down in the middle of winter? If your furnace quits, you won’t have heat. Do you do that with your car? Do you wait until it breaks down and then you’ll have to get out and walk?

If your furnace is 20 years old, it might be better to replace it now so it doesn’t break down on the coldest day of the year. If it breaks when it’s 0 degrees out, then you’re no longer in a position to comfortably shop, consider options, and make a planned purchase. You’re going to be forced into a corner and have to do something immediately. It won’t be a case of “What do I want?” It will be “What can I get?”

I’ve seen instances when a customer has to make the decision, “Who can do it the quickest?” The solution has nothing to do with the brand, or price, or options, or whether you like the HVAC company you’re buying it from. It becomes, “You can put it in tomorrow? You’ve got the job.” It takes all the decision-making out of it.

You wouldn’t do that with a new or used car purchase. Why do it with your HVAC?

Is Your Furnace Safe?

A working furnace doesn’t mean it’s a safe furnace. Each time the furnace cycles, the heat exchanger gets hot, then cold. That piece of metal will get hot and cold only a certain number of times before it’s going to crack.

If the furnace has a crack in the heat exchanger, that’s not safe. It’s going to get worse and it could become unsafe. A properly tuned gas combustion furnace doesn’t produce much carbon monoxide because you have the right gas/air mixture. But when that gas/air mixture is incorrect, then it could start to produce a lot of carbon monoxide. A crack in the heat exchanger can cause that.

I’ve walked into houses before and there’s this sickly, sweet smell of incomplete combustion. And you know right off something’s wrong. If there’s a serious breach, that sort of stuff can kill you. Carbon monoxide is an odorless, colorless gas that can cause nausea and dizziness. Overexposure to this gas is deadly.

Repair Your Furnace or Replace It?

You can always choose to repair a furnace instead of replacing it. The challenge is deciding when repairs are no longer worth the investment. You pay to fix one issue, only for another component to fail soon after. At that point, it's easy to think, "I've already invested so much in this furnace, I should keep repairing it." Unfortunately, that mindset can lead to spending more on repeated repairs than the furnace is ultimately worth.

When the repair costs start to outweigh what a new furnace would cost, that’s a pretty clear call for change.

On sales calls, people ask me all the time to take a look at their furnace and say “What do you think?” I open it up and, for its age, it looks pretty good. Now, I didn’t use any kind of diagnostic tools, and I don’t have a crystal ball. It doesn’t look bad. It might last 10 minutes, it might last 10 years.

Read more: Should I Repair or Replace My Furnace?

I’ve seen examples where the heat exchanger fails, and the customer wants to replace just the heat exchanger. While the heat exchanger itself may be covered under warranty, other components often need to be repaired or replaced at the same time. Labor is also a significant part of the job. Even with a warranty, replacing a heat exchanger is a major repair, and if the system is no longer under warranty, the overall investment can be even greater.

Think of it like a car with very high mileage. If the engine fails and the engine itself is covered under warranty, you still have to decide whether it makes sense to invest in the repair. Even after replacing the engine, there is no guarantee that other major components will not fail. The same principle applies to an aging furnace.

I’ve seen homeowners install a new heat exchanger in a furnace that was more than 20 years old. It is their decision, and we respect it, even if we would have made a different recommendation.

Sometimes I arrive at a home and the homeowner is surprised by the scope of the repair. On an older system, it is important to look beyond the immediate problem and consider the overall condition of the furnace. In many cases, continuing to repair an aging system is not the best long term decision. Instead of focusing on a single repair, it is often more practical to evaluate whether replacement will provide greater reliability and peace of mind.

Signs That It’s Time to Repair or Replace Your Furnace

• If your furnace has started making unusual noises, or if you notice that it doesn’t sound the way it used to, it could be a sign of a failing motor.
• If the temperatures in your home seem more uneven, it could be a sign that your furnace isn’t supplying the power it once used to. When the power dwindles, the air in the ducts doesn’t circulate as well, and you might notice the room at the end of the ductwork has become frigid. 
• It’s not keeping up with the thermostat, or it could be running longer than it used to. Either the heat isn’t as warm as it once was, or the blower isn’t circulating air the way it once did.
• Unusual odors. When motors start to fail, they can give off an electrical burnt smell. Usually, when you get to that point, it’s game over pretty quickly.

• Your electricity or gas bill is creeping up. As motors age, they tend to draw a little more current, and the electrical efficiency will decrease.

Reasons Why You Should Consider a New Furnace

1. Cost. At a minimum, a new furnace with better efficiency represents a savings of hundreds of dollars per year.
2. Comfort. How often are you or a family member in your home? The typical answer I hear is 60-90% of the time. During COVID quarantines, the answer was probably 100% for many homes. Over an entire year, the difference in the quality of comfort will be noticeable by everyone.
3. HVAC equipment doesn’t get cheaper over time. The system you’re considering this year will almost certainly be 3-10% more the following year.
4. Maybe you want to upgrade. You might have a single-stage standard motor furnace and you want to go for more comfort, or want to have the option to install a more sophisticated air conditioner or heat pump. A multi-stage, variable-speed unit would not be compatible with your existing furnace.

Cost and Choice: What's Right For You?

To be clear, the decision on what to do always belongs to the homeowner. A good HVAC technician will educate you on the issues that they’re seeing and, if appropriate, discuss options with you. But you should never feel pushed into a decision.

For those of you who have more questions about furnaces, we have plenty of material that you can read:

How Efficient Is My Furnace?: A Full Analysis

Switching to a Gas or Electric Furnace: Pros, Cons, and Costs

Single-Stage, Two-Stage, and Variable-Speed Furnaces: Differences and Benefits

The Complete Guide to Home Furnaces

The HVAC company that installs your equipment is just as important, if not even more so, than the equipment you install. The reason for this is that the quality of your installation can vary wildly. The best piece of HVAC equipment is only as good as how it’s connected to the rest of your system.

And it’s easy to cut corners in ways that will cost you money and comfort, but it’s hard to spot those things if you aren’t an HVAC professional.

To combat this, you should be prepared with questions that help you to discern the good from the bad. Click the image below to download our HVAC Contractor Checklist, a quick list of questions (and best answers) to help you assess any HVAC company.

The last step is to contact us to schedule your free, no-pressure estimate. You’ll get pricing and a variety of recommendations to match your budget and comfort needs.

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