Should I Repair or Replace My Furnace? A Straight Answer for Marion Homeowners

Your furnace quit, or it’s limping along, and somebody just handed you a repair number. Now you’re standing in the basement, trying to decide if that repair is money well spent.

We’re a family-owned company, and we’ve been fixing and replacing furnaces around Marion since 1969. If this were our own house, this is how we’d work through the decision.

Start with the age

Open the furnace cabinet door and look for the sticker with the model and serial number. The manufacture date is usually printed on it or built into the serial number.

Most gas furnaces last 15 to 20 years. After year 15, ENERGY STAR recommends you start considering a replacement, especially if repairs and gas bills are both climbing.

• Under 10 years old: Repair it, almost every time. Check the warranty first. The part may be covered.
• 10 to 15 years old: It depends on what broke and what it costs.
• Over 15 years old: Any repair that isn’t small deserves a second look.

Then do the math

A couple of simple calculations will get you most of the way there.

• The 50% rule: if the repair would cost more than half the price of a new furnace, you’re better off replacing it.
• The $5,000 rule: multiply the furnace’s age by the repair cost. If you get a number over 5,000, replacement usually makes more sense. A $400 repair on a 9-year-old furnace comes to 3,600, which is an easy yes on the repair. That same $400 repair on an 18-year-old furnace comes to 7,200, and at that point it’s a real question.

These aren’t hard laws. They just keep you from making a big decision on a cold night with a space heater running.

What broke matters more than people think

Small parts like igniters, flame sensors, capacitors, pressure switches and a clogged drain line fail on perfectly good furnaces all the time. Those are usually worth fixing, even on an older unit.

Bigger parts are a different story: a blower motor, inducer motor, control board or gas valve. On a furnace past 15, this is where you want to see the repair price and the replacement price side by side.

A cracked heat exchanger is a safety problem, not a comfort problem. It can let carbon monoxide into the air your family breathes. On an older furnace we don’t think it’s worth repairing, so we’d replace it.

When we’d replace

• It’s past 15 and this is the second repair in two winters.
• Your gas bill keeps going up and your thermostat habits haven’t changed.
• Some rooms never get warm, or the furnace runs constantly to keep up.
• The heat exchanger is cracked.
• You plan to stay in the house long enough to get the benefit.

What nobody tells you about waiting

A furnace rarely quits in October. It tends to quit during the first hard cold snap in January, when every heating company in Grant County is slammed.

If you replace on your own schedule, you get to compare options and pick the efficiency you want. If you wait until the furnace is already down, you take what’s available that week.

There’s also the gas bill. A lot of older furnaces run at about 80% efficiency, and some run lower. That means about 20 cents of every heating dollar goes up the flue. A new high-efficiency furnace runs 95% or better.

Our take

A furnace under 12 or so with a small fix is usually worth repairing. Once it’s past 15 and the repair is a big one, replacement is the better call. If you’re somewhere in between, get both numbers in writing and decide with a clear head.

A good tech should be able to tell you what failed, why it failed and what it costs to fix versus replace, and then let you decide.

Common questions

Is it worth repairing a 20-year-old furnace?

A small part that gets you through the winter can be worth repairing. A major repair usually isn’t worth it. At 20 years the next breakdown is usually not far behind.

How long does a furnace last in Indiana?

A gas furnace typically lasts 15 to 20 years. Ours work hard from October into April, so yearly maintenance makes a real difference in which end of that range you land on.

Can I replace the furnace and keep my air conditioner?

Often, yes, if the AC is in good shape. Have the tech check that the two will work together before you decide.

Need a second set of eyes?

If the furnace can be fixed, our furnace repair team in Marion will take care of it. If it’s time for a new one, you can see how furnace replacement works with us and ask for a furnace replacement estimate. And if the furnace is running fine and you want to keep it that way, you can check what a furnace tune-up costs.

Call Summers Plumbing Heating & Cooling at 765-664-4328. We serve Marion, Gas City, Upland, Fairmount, Hartford City and the rest of Grant and Blackford counties.