Start with the age of the system
Central air systems commonly last around 10 to 15 years, and heavy use in desert heat is at the harder end of that. A system under about 8 years old with a single failed part is almost always worth repairing. Past about 12 to 15 years, a major repair deserves a hard look.
Look at what failed
- Small parts, like capacitors, contactors, fan motors and drain issues, are usually worth fixing on any system in decent shape.
- Big-ticket failures, like a compressor, a leaking evaporator coil or a failed outdoor coil, on an older system are where replacement often wins.
Check the refrigerant
Systems installed before about 2010 often use R-22 refrigerant, which is no longer produced in the US. If an R-22 system has a leak, recharging it gets expensive, and that pushes the math toward replacing it.
Consider comfort and bills
If the system can't keep up on the hottest days even when it's working, or your electric bill keeps climbing, a correctly sized modern system may solve problems that a repair won't.
A simple rule of thumb
Some people multiply the age of the system by the repair cost. If the result is more than the cost of a new system, replacement is worth serious consideration. It's a rough guide, not a law, but it's a useful gut check.
Don't forget the ductwork
A new AC connected to leaky or undersized ducts won't perform the way it should. Any replacement quote should include a look at the ducts. See duct repair.
Getting a clear answer on your system
Questions to ask during a repair visit
Ask what failed, why it failed, and whether anything else is close behind. A failed capacitor on a system with clean coils and good refrigerant pressures is a different story than one on a system with oily residue around the coil and a noisy compressor. A technician should be able to explain the condition of the whole system, not only the broken part.
Signs a compressor is near the end
A compressor that hums but won't start, trips the breaker repeatedly or draws high current on startup may be failing. Loud knocking or grinding from the outdoor unit is another warning. Some of these symptoms come from a weak capacitor, which is a much smaller repair, so testing matters before deciding the compressor is the problem.
Mid-summer breakdown planning
If your system is older and you suspect replacement is coming, planning for it ahead of time beats deciding in July with the house at 90 degrees. Get a sense of what replacement involves now. Our AC installation page lists what a full replacement covers, from load sizing to permits where required.
Maintenance that extends a borderline system
A system in fair shape can often last a few more seasons with regular care: clean coils, a properly working capacitor, the right refrigerant charge and clean filters. A yearly AC tune-up also gives you an honest read on whether the system is wearing out, so the replacement decision isn't a surprise.
Common questions
How long do AC units last in Las Vegas?
Around 10 to 15 years is common. Regular maintenance helps a system reach the longer end.
Is it worth fixing a 15-year-old AC?
For a small repair, it can be. For a compressor or coil failure, replacement is usually the better value at that age.