Furnace Repair or Replacement: How to Decide

If you’re having issues with your furnace, you may be wondering if it’s more economical to try to repair it or whether replacement would make more sense. Here’s the rule of thumb when it comes to furnace repair or replacement: Repair your furnace if it’s less than about 15 years old; the repair costs a fraction of a new system, and it’s been reliable until now. Replace it if it’s older than 15 years, keeps breaking down, needs a major part like a heat exchanger, or your heating bills keep climbing even though your habits haven’t changed. As an example, take an 8-year-old furnace that needs a $350 igniter. Fixing it makes more sense in this case since this unit should have a few more good years. A 17-year-old furnace that needs a $600 blower motor, on the other hand, should be replaced. While you should evaluate furnaces on a case-by-case basis, this rule will give you a good starting point.

ENERGY STAR suggests considering replacement at 15 years. If your furnace is around that age, replacing it with a new model could save you money on heating bills and keep your home’s temperature and humidity level more comfortable. Homeowners who replace their old furnaces are often surprised at how much of a difference this makes on their bills.

How do you know if your furnace is worth repairing?

A furnace is usually worth repairing when it’s still in the first half of its life, the problem is a single part, and the repair costs much less than replacement. Many common repairs fall into that group.

Which furnace repairs are usually worth it?

Igniters, flame sensors, thermostats, capacitors, pressure switches, and draft inducer motors are all common failures, and on a furnace that’s 10 years old or younger, replacing them is almost always worth it. A blower motor on a younger furnace is usually worth fixing too. These parts wear out on their own, and replacing one doesn’t mean the rest of the system is failing.

Which repairs usually mean it’s time to replace your furnace?

A cracked heat exchanger is the clearest sign for furnace replacement. It can let carbon monoxide into your home, and the repair is expensive enough that most homeowners with an older furnace choose to replace the whole unit instead. Replacement also makes sense when a 15-plus-year-old furnace needs a major component like a control board, blower, or inducer, or when you’ve already paid for two or three repairs in the last couple of years. At that point, more repairs rarely pay off.

If you’re not sure which group your repair falls into, our furnace repair team can diagnose the problem and give you a clear quote before any work starts.

How long does a furnace last in Michigan?

Most gas furnaces we service last somewhere around 15 to 17 years with regular maintenance. Keep in mind that Michigan furnaces work harder than most. Our heating season runs from roughly October through April, with plenty of cold days on either side, so a furnace here racks up far more run hours than one in a milder climate.

Maintenance makes a big difference. A furnace that’s had an annual tune-up and regular filter changes can outlast one that’s been ignored for years. If you don’t know how old your furnace is, look for the manufacture date on the data plate inside the furnace door, or ask your technician to check during your next visit.

What are the signs that your furnace needs to be replaced?

Beyond age and repair history, watch for heating bills that rise year after year, rooms that never feel warm, a furnace that runs almost constantly or turns on and off every few minutes, a yellow or flickering burner flame, rust or soot around the unit, and loud banging or rattling. Dry air, extra dust, or a home that feels stuffy can also point to a system that isn’t moving air the way it should. We go deeper into these in our post on furnace warning signs.

One sign on its own doesn’t mean you need a new furnace. When several show up together on a furnace that’s 15 years or older, it’s time to start pricing a replacement.

How much does efficiency matter in the repair or replace decision?

Efficiency matters more the older your furnace is. Furnace efficiency is measured by AFUE, the share of the fuel you pay for that turns into heat in your home. Today’s federal minimum for a standard gas furnace is 80% AFUE, and high-efficiency models reach 95% or more. Many furnaces installed decades ago run well below today’s standards, which means a real part of every gas bill goes up the flue.

Utility rebates can lower the cost of upgrading. DTE Energy’s 2026 rebates pay $100 for a 95% AFUE furnace, $200 for 96% to 97%, and $400 for 98% or higher. Consumers Energy pays $100 for 95% to 96.99% AFUE and $300 for 97% and up. Those programs have limited funding, so check availability when you get a quote.

Two things you shouldn’t count on. The federal 25C tax credit for high-efficiency furnaces ended on December 31, 2025, according to the IRS, so it won’t help with a replacement this winter. And a federal rule that would raise the minimum furnace efficiency to 95% starting in late 2028 is still tied up in court, with a possible delay under review. We wouldn’t base a decision today on either one.

Don’t Wait Until Winter to Decide on Furnace Repairs

We encourage homeowners to service their furnaces in the fall so any issues can be detected and addressed before the freezing weather. This is a great time to get a tune-up and ask your technician for a read on your furnace’s condition. It’s also much easier to schedule a replacement in the fall than when your furnace fails in the middle of winter.

Of course, unexpected issues can arise anytime. If your furnace suddenly stops working or has to work extra hard to keep the heat up, contact Ehlers Heating and Cooling at (248) 442-8500. We’re also available for emergencies after hours.

Furnace Replacement with Ehlers

A good replacement starts with sizing. We look at your home’s size, insulation, windows, and ductwork to recommend a furnace that fits. An oversized furnace short-cycles and wears out faster, and an undersized one runs nonstop on the coldest nights. Then we walk you through efficiency options, rebates that apply, and what each choice means for your monthly bills, so you can pick what makes sense for your budget.

As a Carrier Factory Authorized Dealer with NATE-certified technicians, we handle the removal, installation, permits, and startup, and we’ll show you how to maintain the new system. Learn more on our furnace replacement page.

How long does it take to replace a furnace?

Many standard furnace replacements are finished in a single day. Jobs that need ductwork changes, new venting, or a switch to a different type of system can take longer, and your estimate should tell you what to expect.

Can you replace the furnace without replacing the air conditioner?

Often, yes. But the furnace blower moves air for your central AC too, so the two systems need to be compatible. If your air conditioner is also getting older, replacing both at once can save on labor and help the system run more efficiently.

Schedule Your Furnace Inspection Today

Ehlers Heating & Cooling has helped homeowners in Plymouth, Livonia, and across western Wayne and southern Oakland County with their HVAC systems for more than 50 years. We’re family-owned, and we’ll give you an honest recommendation based on your furnace’s age, condition, and repair history.

Call (248) 442-8500 or request service online to schedule a diagnostic or get a replacement estimate.