Should I Repair or Replace My Furnace?

Use the 50% rule: if the repair costs more than half the price of a new furnace, replace it. For example, if a new furnace costs $4,500 and the repair quote is $2,400, replacement is the smarter move. If the repair is $600 and the furnace is under 12 years old, repair usually makes sense. Here's how to make the right call for your situation.

Here's an easy formula that takes the guesswork out of it. If the repair costs more than 50% of a new furnace, replace it. For example: if a new furnace costs $4,500 and the repair quote is $2,400, you're better off putting that money toward a brand-new system with a fresh warranty and years of worry-free heat ahead. If the repair is $600? That's probably worth doing - especially if the furnace is under 12 years old. Not sure what repairs cost? Check our furnace repair cost breakdown.

Some HVAC pros use a second formula alongside the 50% rule: multiply the furnace's age by the repair cost. If the answer is over $5,000, replace it. A 14-year-old furnace with a $400 repair = $5,600. That's a replace. A 6-year-old furnace with the same $400 repair = $2,400. That's an easy fix. Use both rules together and the answer is usually clear. If you're not sure how old your furnace is, check the metal data plate inside the access panel - it lists the manufacture date.

Every dollar you put into a dying furnace is money you'll never get back. Older furnaces (15+ years) run at 60–80% efficiency. New ones hit 95–98%. That gap means your monthly heating bills are higher - on top of the repair bills. The U.S. Department of Energy confirms that modern furnaces are dramatically more efficient. And there's the risk factor: what happens when it fails on the coldest night of the year, and every HVAC company in town is booked?

If your current furnace runs at 70% AFUE and you upgrade to a 96% AFUE model, you're not paying to heat your basement and attic anymore - that wasted energy stays in your living spaces. For a typical Central Illinois home spending $1,400–$1,800 per winter on heating, the upgrade can cut bills by $350–$550 per year. Over a 15-year lifespan, that's $5,000–$8,000 back in your pocket - often more than the price difference between repair and replacement. See our new furnace cost breakdown for current pricing in the Peoria area.

• It's over 15 years old with no major upgrades
• Your bills keep climbing even though your habits haven't changed
• Some rooms are warm, others are cold - uneven heating
• Yellow pilot light - this can mean a cracked heat exchanger (safety risk)
• It's getting louder - banging, rattling, squealing

If you're nodding along to two or three of these, your furnace is telling you something.

Replacement isn't always the answer. Repair usually makes sense when: the furnace is under 10 years old, the repair is under $500, it's the first major issue you've had, and the system is still running at decent efficiency. A blown capacitor, a bad flame sensor, or a worn ignitor are all routine repairs - not reasons to replace a perfectly good furnace. If you're seeing common issues like cold air from the vents or a furnace that won't turn on, those are often quick fixes - not death sentences.

Yes - and this is where the math stops mattering. A cracked heat exchanger can leak carbon monoxide into your home. The CDC reports over 400 Americans die each year from accidental CO poisoning, and faulty furnaces are a leading cause. Signs of a cracked heat exchanger include soot around the burners, a yellow flame instead of blue, persistent headaches when the heat is running, or your CO detector going off. If you suspect this, don't repair it - replace it. No price tag is worth that risk. Make sure your CO detectors have working batteries, especially through Illinois winters.

Before any HVAC company shows up, gather a few things:

• The furnace's age and model number (on the data plate inside the access panel)
• Your last 12 months of utility bills - so you can see if heating costs have crept up
• A list of repairs from the past 3 years and what they cost
• Notes on which rooms feel uneven or whether the furnace cycles too often

This info helps a good technician give you a real recommendation - not a sales pitch. Get at least two written quotes and make sure each includes a proper load calculation, not just a guess based on your old unit's size. For more on right-sizing, see what size furnace you actually need.

We'll never push a replacement when a repair makes sense. And we'll never patch a system that's putting your family at risk. We give you the full picture: repair cost, how much life is left, and replacement options with upfront pricing. We serve homeowners across Peoria, Pekin, Morton, Washington, and the surrounding Central Illinois area. If repair is the right call, see our furnace repair services. If it's time to replace, browse new furnace installation options or read our winter maintenance checklist to protect your next system. We also offer flexible financing with approved credit. To keep your home trouble-free, call (309) 347-5309 or schedule a free assessment. You deserve a straight answer - and that's what Trouble Free gives you.