Furnace Repair vs Replace
The repair-or-replace call comes down to three numbers: the furnace's age, the repair quote, and the heat exchanger's condition. Here's how we make the call when it's our own money.
Repair
Fix the failed part, keep the system
- Most furnace repairs are $250–$900 — ignitors, flame sensors, capacitors, board relays
- Right answer for any furnace under 12 years old with a sound heat exchanger
- Same-day fix in most cases; no permits, no install crew
- Buys time to plan a replacement on your schedule instead of in a January emergency
- Repairs stack — the blower motor this year doesn't make the inducer next year any younger
- An 80% AFUE furnace keeps burning 16% more gas than a 96% unit every month you keep it
- Cracked heat exchanger ends the conversation — that's a CO safety issue, not a repair candidate
Furnaces under 12–15 years, first major failure, repair quote under 50% of replacement cost, sound heat exchanger.
Replace
New 96% AFUE system, 20-year reset
- 96% AFUE vs an old 80% unit cuts the gas portion of the bill ~16%
- 10-year parts warranty resets the repair-cost clock to zero
- Two-stage and variable-speed options fix comfort complaints repairs never will
- High-altitude orifice kit + correct Manual J sizing done right this time
- Replacing in fall shoulder season beats replacing during a January cold snap at emergency pricing
- Real money: $5,000–$8,000 installed for quality equipment
- A day of install disruption, permit, and inspection
- Oversized 'bigger is better' replacements short-cycle — insist on a load calculation
Furnaces past 15 years, cracked heat exchangers, repair quotes over 50% of replacement, repeat failures two winters running, or anyone planning to add AC or a heat pump anyway.
Our Recommendation
Use the 50% rule: if the repair quote exceeds half the cost of a comparable new furnace AND the unit is past 12 years, replace. Under 12 years with a sound heat exchanger? Repair it — almost every time. The one non-negotiable: a cracked heat exchanger means replacement, full stop. And get the heat-exchanger claim verified — ask to see the crack on camera. It's one of the most over-diagnosed 'failures' in the industry, and a free second opinion is cheaper than a furnace.
Common Questions
How long should a furnace last in Utah?▼
15–20 years for a maintained gas furnace, sometimes 25 for a single-stage workhorse. Utah's high-altitude combustion runs slightly rich unless the furnace was properly orificed at install — un-derated furnaces age their heat exchangers faster, which is why some local units die at 12 and others cruise to 22.
A company says my heat exchanger is cracked. Should I just believe them?▼
Verify it. A real crack is visible on camera or detectable with a combustion analyzer reading. It's also the single most common pressure tactic in the industry because it converts a $300 repair call into a $7,000 replacement. We give free second opinions on heat-exchanger diagnoses — if it's truly cracked, we'll show you.
Is it worth replacing a working 80% furnace with a 96% one?▼
On gas savings alone, rarely — the payback is 10+ years. It becomes worth it when the 80% furnace is already past 15 years, when you're adding AC or a heat pump (shared blower), or when comfort problems (cold rooms, short cycling) need the variable-speed blower anyway.
Still on the fence?
Free in-home estimates with both/all options quoted side-by-side. No pressure, no obligation — just the numbers for your home.
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