HVAC repair or replace calculator

The $5,000 rule for HVAC: what it is and why it needs an update

The $5,000 rule is the most common rule of thumb for the HVAC repair-or-replace question. Multiply your system's age in years by the cost of the proposed repair. If the result is over $5,000, lean toward replacing. If under, lean toward repairing. A 10-year-old AC with a $400 capacitor repair is 4,000, which says repair. A 14-year-old heat pump with a $900 compressor issue is 12,600, which says replace.

The rule was created when central AC installs ran three to five thousand dollars. Today a 3-ton AC install runs seven to ten thousand, a heat pump install runs eleven to sixteen thousand, and a high-efficiency furnace runs five to eight thousand. The fixed $5,000 cutoff was never adjusted for inflation or for changing equipment costs, so it pushes too many homeowners toward expensive replacements when a $700 repair on a healthy 8-year-old system would have been the better call. This calculator uses an updated threshold of $7,000 for AC, $8,000 for heat pumps, $6,500 for furnaces, and $5,000 for mini-splits, which reflects current install pricing.

The 50% rule: a sharper sanity check against the repair quote

The 50% rule is the second-most-used heuristic. If a single repair quote exceeds half the cost of a comparable full replacement, replace the system. A $4,500 compressor repair on an AC that costs $7,800 to fully replace is a clear replace. A $400 motor swap on the same AC is a clear repair. The 50% rule is sharper than the $5,000 rule because it scales with the actual cost of the system you would buy.

The 50% rule is most useful for big-ticket repairs: compressor failures, coil replacements, heat exchanger cracks, and complete refrigerant recharges on R-22 systems. For routine repairs under $800, the 50% rule almost always says repair, which is the right answer most of the time on a healthy unit.

Refrigerant phase-out: the hidden cost most quotes ignore

The refrigerant your system uses changes the repair-or-replace math more than most homeowners realize. R-22 has been banned for production and import for several years and is now sold only from recycled or reclaimed stock at four to ten times its pre-ban price. Any R-22 system that needs a refrigerant recharge is effectively scrap value, because a 5-pound recharge can cost $700 to $1,500 on its own, and the same leak will return.

R-410A, the workhorse refrigerant in residential equipment for the past decade and a half, is being phased out for new equipment under the AIM Act. Production for new systems has ended, and service stock will tighten and rise in price over the next several years. Replacement equipment uses R-454B or R-32, which are not interchangeable with R-410A. An older R-410A unit needing major refrigerant work today is in a similar spot to where R-22 systems were several years ago: technically serviceable, increasingly expensive, and on borrowed time.

When age alone makes replacement the right call

System lifespan caps the entire conversation. A central AC has a typical useful life of 13 to 15 years. A heat pump runs 12 to 15 years because it works both summer and winter. A gas furnace can run 18 to 25 years if the heat exchanger stays intact. Mini-splits fall in the 13 to 16 year range. Outside those windows, you are repairing equipment that is statistically due to fail somewhere else in the next 12 to 24 months.

If your AC or heat pump is over 14 years old, replace it on the next significant repair even if the dollar math is borderline. The hidden cost of repeated service calls, declining efficiency, and the inevitable second failure during a heat wave or cold snap is real. Most homeowners regret the third $600 repair on a 15-year-old unit more than they would have regretted replacing it at year 13.

How a string of repairs signals decline you cannot see

Two or more repairs in the past 24 months is a strong signal the system is in decline. HVAC components rarely fail in isolation: a failing compressor stresses the contactor and capacitor, a marginal blower motor loads the run capacitor, and a clogged condensate line accelerates corrosion on the evaporator coil. By the time you have paid for three repairs in two years, you have usually paid more than 30% of a full replacement and still have a system with a shorter remaining life than a new one.

Keep records of every service call: date, part, cost, and contractor. When the running total in the past two years crosses 40% of a new install, the answer is replacement, not another repair. The calculator factors recent repair history into the recommendation automatically.

The efficiency savings most repair-vs-replace decisions undercount

A 15-year-old central AC running at SEER 10 to 12 (the standard from 2010 to 2015) uses roughly 25 to 35 percent more electricity than a new SEER2 16 unit doing the same cooling work. On an $1,800 annual cooling bill, that is $450 to $630 per year going straight out the window in efficiency loss. Over 10 years of remaining ownership on a new system, that is $4,500 to $6,300 in pure energy savings, before any rebate stacking.

The numbers are even larger on heating. A 78 AFUE furnace from the 1990s costs 23 percent more to run than a new 96 AFUE condensing furnace. Replacing electric resistance heat with a heat pump cuts heating energy use by two thirds in most climates. These savings do not appear on the repair quote, but they should be in the decision. Use our payback period calculator after this tool to confirm the replacement pays back inside the equipment's useful life.

Common HVAC repairs and what they signal about replacement

Some repairs are routine on any age system. Some are red flags that the system is on its way out. The repair itself tells you more than the dollar amount:

• Capacitor or contactor: $150 to $400. Normal wear, fix on any age system.
• Condenser fan motor: $400 to $750. Fix if under 10 years, weigh carefully if over.
• Blower motor: $500 to $900. Same logic as fan motor.
• Compressor: $1,800 to $3,500. Almost always a replace decision on units 10+ years old. The compressor is the most expensive single part on the system.
• Evaporator coil with refrigerant leak: $1,500 to $2,800. Major red flag, especially on R-410A or older systems. Strong replace signal.
• Heat exchanger crack (furnace): $1,500 to $3,500. Safety issue (carbon monoxide). Most contractors will not warranty the repair. Replace.
• Refrigerant recharge larger than 2 lbs: indicates an active leak. Find and fix the leak, do not just refill. On R-22 systems, this is a replace decision.

How to use this calculator with a contractor quote in hand

Before you accept any repair quote, run the numbers here. If the recommendation is repair, get the work done and move on. If the recommendation is replace with high confidence, push back on the contractor and ask for a replacement quote instead. If the recommendation is borderline, get a second opinion on the repair. Borderline cases often involve a contractor pushing replacement on a system that has another five good years in it, or pushing repair on a system that will fail again within the year.

Always pair this tool with the rebate finder when leaning toward replacement. Federal HEAR rebates, state programs, and utility incentives can drop the effective replacement cost by 30 to 60 percent for income-qualified homeowners. A replacement that looks expensive at sticker price often becomes the obvious choice once stacked rebates are in the math.