Repair or Replace Your Furnace?
Updated June 2026 · 6 min read
Repair your furnace if it's under about 15 years old, the fix is minor, and it's running safely. Replace it if it's 15–20+ years old, needs a major part, or shows any sign of a cracked heat exchanger — because that's a carbon-monoxide risk, and safety overrides the math every time. Age, repair cost, safety, and efficiency are the four things to weigh.
How long does a furnace last in the DMV?
A well-maintained gas furnace typically lasts 15–20 years. The DMV's winters aren't as long or brutal as New England's, so a furnace here often reaches the upper end of that range — provided it's had regular service. Under about 15 years, a furnace is usually worth repairing. Past 20, you're maintaining borrowed time, and a single major repair is rarely worth it. Where it gets interesting is the gray zone in between, where age, the repair bill, and safety all come into play.
When is it a safety issue, not a money question?
Some furnace problems aren't about dollars at all. A cracked heat exchanger can let carbon monoxide — a colorless, odorless gas — leak into your home's air. If a technician finds a cracked or failing heat exchanger, the honest answer is almost always to replace the furnace and stop running it in the meantime. The same goes for repeated safety lockouts or a furnace that keeps tripping its limit switches. No repair savings are worth an air-quality or CO risk to your family. Make sure you have working carbon-monoxide detectors on every level regardless of your furnace's age.
How do you weigh repair cost against a new furnace?
When it's not a safety call, use the same gut-check the trades use for any HVAC equipment: multiply the furnace's age by the repair cost, and if the number climbs past about $5,000, replacement usually wins. Routine parts — igniters, flame sensors, capacitors — are cheap and worth fixing. The repairs that tip an older furnace toward replacement are the big ones:
- Heat exchanger — expensive, and a crack is a safety issue (see above).
- Control board or gas valve — pricey electronics on aging equipment.
- Inducer or blower motor — a major repair that often signals more to come.
Before assuming the worst, diagnose it — our guide to why a furnace blows cold air covers the common, fixable causes. To compare real numbers, see the furnace replacement cost guide for the DMV, or run the repair-or-replace tool in our Learning Center.
The short version
Safety first: any cracked heat exchanger or CO risk means replace, full stop. Otherwise, repair a furnace that's under ~15 years old and needs a minor fix; lean toward replacement once it's 15–20+ years old, needs a major part, or its efficiency is dragging your gas bills up.
Should you replace it — or switch to a heat pump?
A replacement is also a chance to rethink how you heat. Furnace efficiency is measured in AFUE — the percentage of fuel turned into usable heat — and a modern high-AFUE furnace wastes far less than a 20-year-old unit. But many DMV homeowners now weigh an electric heat pump instead, which both heats and cools on one efficient system and earns the largest rebates. Our guide on AC vs. heat pump lays out the trade-offs, and a dual-fuel setup can pair a heat pump with a gas furnace for the coldest snaps. There are rebates and tax credits that make the efficient choice easier to afford.
Get an honest recommendation before winter
We won't frighten you into a furnace you don't need, and we won't band-aid one that's unsafe just to make a sale. As a union (UA Local 602) contractor and Trane Comfort Specialist, our techs will show you what's wrong, give you the repair and replacement numbers side by side, and let you choose. If replacement is right, our free in-home estimate includes a Manual J calculation so the new system is sized for your home. Explore our heating services, see how the same logic applies to your AC, and request a free estimate when you're ready.