Replace or repair?

Should I replace my air conditioner?

Replace it if the compressor has failed on a unit past 10 years, if it uses R-22 refrigerant and has a leak, or if a repair would cost more than a third of a new system. Replace a capacitor, contactor or fan motor and keep going.

Replace it now if

The compressor has failed and the unit is 10 or more years old. A compressor is the most expensive part and a new one in an old system is a bad bet.
The system uses R-22 (most units built before 2010) and has a refrigerant leak. R-22 is no longer produced, the gas is costly, and the leak will return.
The indoor evaporator coil is leaking on a system past 12 years. The coil and the outdoor unit should be matched, so a coil-only fix on an old system is money half spent.
It cannot hold the house at temperature on an ordinary hot day and the charge, coil and filter are all fine. It is undersized or worn out.

Repair it if

It is not cooling and the fix is a capacitor, contactor, fan motor, thermostat or a clogged condensate drain. These are the common failures and none of them says anything about the compressor.
The coil froze because the filter was filthy or the blower stopped. Fix the cause.
It is under 10 years old, uses R-410A or newer refrigerant, and has a small leak a technician can find and repair.

Use the one-third rule

A repair over a third of a new installed system on a unit past 10 to 12 years means replace. Add efficiency: a 10 SEER unit from the early 2000s replaced by a 15 to 16 SEER2 unit uses roughly a third less electricity for the same cooling. In a long cooling season that is real money; in a short one it is a tiebreaker.

What replacement involves

The outdoor unit and the indoor coil are replaced together, and the refrigerant line set is flushed or replaced. If your furnace is also old, a matched system or a heat pump replacing both is worth pricing. New systems use R-454B or R-32 refrigerant; that is normal and not a reason to hesitate. Have the installer size from a load calculation rather than copying the old unit's tonnage.

If you are not replacing yet

Clean the outdoor coil, change the filter, and have the charge checked. Keep the model and serial, the install date and this decoder's result with your house records so the next technician does not have to guess.

Check the age first

The decoder on the home page reads the build date out of the serial number for 53 brands.

How long does a central air conditioner last? · How long does a heat pump last?

Parts that help it last

Furnace and AC filters The same filter protects the blower and the coil. Match the size on the old one.
Leak alarm A clogged condensate line is a common AC leak. An alarm under the indoor coil catches it early.

Check your model and size before you buy. Amazon links are affiliate links: as an Amazon Associate I earn from qualifying purchases.

Keep a record of your home

The age you just looked up is the kind of fact that gets lost. A written record of serial numbers, install dates, repairs and who did the work saves the next owner, inspector or insurer from guessing.

Keep This With the House

A lifetime logbook for the house, organized by system, with room for serial numbers, install dates, repairs and contractors. It stays with the house for the next owner.

Paperback

The House Has Old Pipes

Galvanized, polybutylene, cast iron and the sewer line: what fails, what it costs, what insurance won't cover and how to decide.

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The House Is Fifty Years Old

A buyer's guide to older homes: wiring, pipes, lead, asbestos, insurance refusals and what the repairs actually cost.

Paperback · Kindle

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