What is the $5,000 rule for AC?

How the rule works

The math is one multiplication:

age of the system (years) x repair cost (dollars) = the number

Over 5,000, start looking at replacement. Under 5,000, repair it. The idea is that a big repair on an old system buys you a few years at most, and the same money goes a long way toward a new one. A small repair on a young system is almost always worth doing.

Nobody official sets the threshold. You will find it on contractor websites and forums, sometimes with a different cutoff. I treat it as a starting point for a conversation with the technician, and a check on a quote that pushes replacement too early or a repair too late.

Worked examples

These are hypotheticals, with repair prices taken from the published ranges on our cost page.

System age	Repair	Quote	Age x cost	Rule says
14 years	Capacitor	$200	2,800	Repair
6 years	Condenser fan motor	$600	3,600	Repair
12 years	Leak repair and recharge	$800	9,600	Consider replacing
4 years	Compressor	$2,000	8,000	Consider replacing (but see below)
15 years	Compressor	$2,500	37,500	Replace

The first and last rows are easy. Say your 14 year old system stops cooling and the technician finds a failed capacitor. This Old House puts that repair at $80 to $400 installed. A $200 repair on a 14 year old system scores 2,800: fix it, and start saving for the replacement. A compressor on a 15 year old system is the opposite. Fixr lists compressors at $600 to $3,000, and a new central system at $5,800 to $14,400. Putting most of the price of a new system into an old one is a poor trade.

The middle rows are where the rule needs judgment, which is the next section.

Where the rule falls short

It ignores the warranty. The 4 year old system in the table "fails" the rule, but a compressor that young may still be under the manufacturer's parts warranty. Ask before you price a new system. The rule would have you replace a system that might only owe you labor.

It ignores the refrigerant. A leak on an R-22 system and a leak on an R-410A system score the same, but they are different decisions. Fixr lists R-22 at $50 to $80 a pound and R-410A at $12 to $25. An R-22 leak tends to come back as a bill every summer. An R-410A system can still be serviced and repaired under EPA rules, so a technician who says it can't is wrong about the rule.

It ignores Cape Coral conditions. Salt air corrodes outdoor coils on canal and Gulf homes, and a coil corroded through will leak again after a patch. The rule does not know your coil is rotting. The climate also adds hours: Page Field now averages 145 days a year at 90°F or hotter, so a 10 year old system here has worked harder than the age suggests.

It ignores humidity. A system that keeps the house at 76°F but leaves it damp is failing at half its job. If an oversized system is the cause, no repair fixes that, and the rule will keep telling you to repair it. The DOE says oversized systems remove less moisture.

It ignores your plans. If you are selling next year, a repair that scores 6,000 may still be the right call. If the house is your long-term home and the system is near the 12 to 15 year life This Old House gives, replacing on your schedule beats replacing in August with no AC.

And it uses a fixed threshold while prices move. Treat 5,000 as a rough line, not a bright one.

Use it with the other questions

The rule is one input. The full checklist is on our repair or replace page: age, repair size, refrigerant, salt air and humidity. If a quote pushes you toward replacement and the rule disagrees, ask for the failed part by name and a photo, and get a second opinion. Our guide to checking whether a quote is fair covers what to ask.