FTC disclosure. This guide has no affiliate links to repair services or new equipment purchases. Where we point to specific heat pump models, those come from our separately-vetted cold-climate heat pump buying guide, which does carry manufacturer and installer links per that guide’s own disclosure.
TL;DR. Multiply your unit’s age in years by the repair quote in dollars. If that number is over $5,000, replace. Under $5,000, repair is usually fine, unless your system runs on R-22 refrigerant. In that case, replace regardless of the math (R-22 production and import have been banned in the U.S. since 2020, and remaining supply is priced accordingly). A $600 repair on a 4-year-old AC is an easy repair call. A $2,800 repair on a 14-year-old furnace ($39,200 by the formula) is an easy replace call.
The $5,000 rule
This is the shorthand HVAC technicians and Consumer Reports both use, and it holds up because it approximates the real tradeoff: age × repair cost.
“ unit age (years) × repair quote ($) = decision number “
- Under $5,000: repair. The unit still has useful life left relative to what you’re paying to extend it.
- Over $5,000: replace. You’re paying too much, on a system too old, to make the repair pencil out before it breaks again.
Worked examples:
| Unit age | Repair quote | Decision number | Call |
|---|---|---|---|
| 3 years | $450 | $1,350 | Repair |
| 8 years | $900 | $7,200 | Replace |
| 12 years | $1,100 | $13,200 | Replace |
| 6 years | $380 | $2,280 | Repair |
The rule breaks down at the edges. A 2-year-old unit with a $3,000 compressor failure (decision number $6,000, technically “replace”) is usually still worth repairing if it’s under warranty, because the part is free and you’re only paying labor. Read the rule as a starting point, not a verdict, and check the three exceptions below before you commit.
Want the math run for you instead of doing it by hand? Thermostating’s repair-or-replace calculator takes your unit’s age and repair quote and applies this same formula, plus the R-22 and efficiency adjustments covered below.
Three things that override the math
1. R-22 refrigerant means replace, full stop
If your system’s data plate says R-22 (sometimes labeled “HCFC-22” or the brand name Freon), the repair-vs-replace math doesn’t apply the normal way. The U.S. banned production and import of R-22 as of January 1, 2020 under the Clean Air Act’s ozone-protection rules. What’s circulating now is reclaimed or stockpiled supply, and it is not getting cheaper.
A refrigerant leak repair on an R-22 system routinely runs $1,500–$3,500 just for the refrigerant charge, on top of the actual leak fix. On a unit old enough to still be running R-22 (anything installed before roughly 2010), that repair cost alone usually clears the $5,000 rule’s threshold on its own, before you’ve paid for labor or parts.
Skip the math and replace if: your system is R-22 and the repair involves a refrigerant leak, a compressor, or anything that opens the refrigerant circuit. A blown capacitor or a bad thermostat on an old R-22 unit is still worth fixing; those don’t touch the refrigerant.
Not sure how much refrigerant your system even holds, or what a fair recharge price looks like? Thermostating runs both: how much refrigerant does my AC hold estimates the charge by tonnage, and their refrigerant leak cost calculator prices out the repair by refrigerant type.
2. Repair cost as a share of replacement cost
If the repair quote is more than 50% of a new system’s installed cost, replace, even if the age × cost math says repair. A $2,000 repair on a system where full replacement runs $6,000 installed is 33% of replacement cost, a reasonable repair. The same $2,000 repair on a $3,500 mini-split system is 57% of replacement cost. You’re most of the way to paying for a new one anyway, minus the warranty.
3. Efficiency losses you’re not pricing in
A repaired 12-year-old AC running SEER 10–13 costs meaningfully more to operate than a new SEER2-rated system (federal minimums moved to SEER2 14.3 for most of the country starting 2023). On a typical 3-ton system running 1,200 cooling hours a year, the efficiency gap between an old SEER 10 unit and a new SEER2 16 unit is roughly $250–$450 a year in electricity, depending on your local rate. Factor 3–5 years of that gap into the repair side of the decision. It’s a real cost even though no one hands you an invoice for it.
Repair vs. replace by equipment type
Central air conditioner. Compressor failure on a unit over 10 years old is almost always a replace call; compressors run $1,800–$2,800 to replace and carry the highest failure-recurrence risk of any AC part. Capacitor, contactor, or fan motor failures are cheap ($150–$600) and worth fixing at any age under 15 years.
Heat pump. Same logic as AC plus one wrinkle: a heat pump that’s losing heating capacity (not just cooling) below 30–40°F outdoor temp on a system rated for cold climates is often a refrigerant charge or reversing valve problem, not a sizing problem. Reversing valve replacement runs $1,200–$2,200 and is worth doing on units under 10 years old; past that, it’s usually bundled into a replace decision.
Furnace. A cracked heat exchanger is a safety issue, not just a repair decision. It’s the #1 reason a furnace repair quote should trigger an automatic replace conversation regardless of age, because a cracked exchanger can leak carbon monoxide into the house. Have your technician show you the crack (borescope photo, not just a verbal claim) before signing off on a full furnace replacement based on this alone; misdiagnosed heat exchanger cracks are a documented cause of unnecessary premature replacements.
Boiler. Boilers routinely run 20–30 years, longer than any other HVAC category, which shifts the $5,000 rule’s age multiplier meaningfully. A 15-year-old boiler with a $2,000 repair (decision number $30,000) still often makes sense to repair if the core heat exchanger is intact, because boiler replacement costs ($6,000–$15,000+ for cast iron) are high enough that the “50% of replacement cost” rule (see above) usually overrides the raw age math.
What replacement actually costs in 2026
Ranges below are installed cost, not equipment-only cost, and assume no major ductwork or electrical panel upgrade is needed. Add $1,500–$4,000 if your panel needs upgrading for a heat pump, or if ducts need resizing.
| System type | Installed cost range | Typical lifespan |
|---|---|---|
| Central AC (3-4 ton) | $4,500–$8,500 | 12–17 years |
| Ducted heat pump (whole-home) | $8,000–$15,000 | 15–20 years |
| Ductless mini-split (2 zones) | $5,000–$8,000 | 15–20 years |
| Gas furnace | $3,800–$7,500 | 15–20 years |
| Boiler (cast iron) | $6,000–$15,000 | 20–30 years |
If you land on “replace” and you’re deciding between a heat pump and a like-for-like furnace/AC swap, our cold-climate heat pump buying guide covers the ducted-vs-ductless decision and names specific 2026 model picks (Mitsubishi Hyper-Heat, Bosch IDS 2.0, Fujitsu Halcyon) with AHRI-verified cold-climate performance data.
Get a second repair quote before you decide either way
Repair-vs-replace math is only as good as the quote it’s built on. HVAC repair pricing varies more than most home-service categories. The same compressor failure can be quoted anywhere from $1,600 to $3,200 depending on the company. Before you commit to either side of the decision:
- Get two independent quotes, not two quotes from the same company’s different techs
- Ask each company to itemize parts vs. labor. A $2,800 “compressor replacement” that’s $600 in parts and $2,200 in labor is worth a second opinion
- If a technician recommends replacement, ask them to show you the failed component, not just describe it verbally
- Run the quote through Thermostating’s quote checker before you sign anything — it flags line items that are priced well outside the normal range for the part and labor described
Skip this guide’s math if…
- Your system is under manufacturer warranty: repair almost always wins regardless of the $5,000 rule, because the part itself is free
- You’re planning to sell the house within 12 months: a working repaired system is usually a better return than a new system you won’t get full value back on at sale
- You’re mid-way through financing an existing system: check the payoff terms before adding new equipment debt on top
Frequently asked questions
What is the $5,000 rule for HVAC? Multiply your system’s age in years by the repair quote in dollars. If the result is over $5,000, replace the system instead of repairing it. It’s a rule of thumb, not a formula that accounts for every situation. See the three exceptions above.
Is it worth repairing a 15-year-old AC unit? Usually no, unless the repair is cheap (under $400) and doesn’t involve the compressor or refrigerant circuit. At 15 years, most systems are within a few years of end-of-life regardless, and a major repair rarely buys more than 2-3 years before the next failure.
How much does it cost to replace R-22 refrigerant? $1,500–$3,500 for a full recharge on an average residential system, driven by reclaimed R-22 pricing running well above what R-410A or newer refrigerants cost per pound. This is on top of whatever caused the leak in the first place.
Should I repair or replace a furnace with a cracked heat exchanger? Replace. A cracked heat exchanger is a carbon monoxide safety risk, not a routine repair. Ask for photo documentation of the crack before agreeing to replacement so you know it’s a real finding, not an upsell.
Does a heat pump last as long as a furnace? Roughly the same range, 15-20 years, though heat pumps run more hours per year than a furnace alone (they handle both heating and cooling), which can push wear toward the shorter end of that range in high-usage climates.
Where this fits
- Replacing? Start with our cold-climate heat pump buying guide for specific 2026 picks and installed-cost scenarios.
- Curious what changed for heating equipment incentives? See our IRA 2026 homeowner guide for what rebate money is still available post-25C.
- Not sure your HVAC problem is even the equipment? Check for duct leaks, insulation gaps, and thermostat placement issues first. A repair-vs-replace decision on a correctly-sized, well-installed system is very different from one on a system that was always fighting a leaky envelope.
- Want more calculators? Thermostating’s full HVAC calculator hub covers sizing (AC size, BTU, Manual J load) and running cost, beyond just the repair-or-replace math above.
Sources
- EPA — Section 608 Refrigerant Phaseout (R-22)
- ENERGY STAR — Central Air Conditioning
- Consumer Reports — Should You Repair or Replace Your Air Conditioner
Update log
- 2026-09-01 — Initial publish.
