Quick answer
An AC compressor is the most expensive part in a central air conditioner, and replacing it sits well above the $150–$800 band that covers most AC repairs; the total is often close to the cost of a new unit at $3,500–$7,500 installed. If the unit is under 10 years old and registered, the part may still be under warranty. On an older or R-22 system, replacement usually wins.
Asking how much an AC compressor costs to replace is usually the start of a repair-or-replace decision, and that is the way to treat it. The compressor is the pump at the heart of the outdoor unit, sealed in a steel shell, and swapping it is a full day of skilled work with refrigerant recovery, brazing, a new filter-drier, a vacuum and a fresh charge. The bill lands well above the $150–$800 range that covers nearly every other AC repair, and it often comes within reach of a new air conditioner at $3,500–$7,500 installed.
What drives the compressor price
- The part: sized to the unit's tonnage and matched to its refrigerant. A scroll compressor for a 3-ton R-410A condenser is a different part from the reciprocating compressor in a 1990s R-22 unit, and the older one is harder to source.
- Refrigerant: the entire charge is recovered, then replaced. On R-22 equipment that alone is a significant line on the invoice.
- Labour: cutting out and brazing in the compressor, replacing the liquid-line filter-drier (required whenever the system is opened), pulling a deep vacuum and weighing in the charge.
- Burnout cleanup: if the old compressor failed electrically and acid is in the lines, a suction-line drier and a flush are added, or the contamination takes out the new compressor too.
- Related parts: a new capacitor and contactor are normally replaced at the same time, since a weak capacitor is often what wore out the old compressor.
Warranty changes the math
Most manufacturers cover the compressor as a part for 10 years when the equipment was registered within the window after installation, and some offer longer terms on the compressor specifically. Under warranty you pay labour, refrigerant and the drier, not the part, which brings the job back into a range worth considering on a seven- or eight-year-old unit. Check the registration before anyone quotes you; the model and serial number on the outdoor unit's data plate are what the manufacturer looks up.
How a technician confirms the compressor is dead
A humming, non-starting condenser is far more often a capacitor than a compressor, which is why the diagnostic comes first. The technician checks the capacitor, then measures resistance across the compressor windings: an open winding or a short to ground is a failed compressor, while a compressor that starts with a hard-start kit is not dead yet. Locked-rotor amps and the internal overload are checked as well. If anyone condemns a compressor without a meter, get a second opinion; the capacitor answer explains how often the small part is the actual fault.
Repair or replace: the decision by age and refrigerant
- Under 10 years, R-410A, warranty part: replacing the compressor is often the right call.
- 10 to 15 years, R-410A, out of warranty: the compressor price is usually a large fraction of a new unit, which brings a fresh warranty, better efficiency and current refrigerant. Replacement usually wins. See is it worth repairing a 10-year-old AC.
- Any age on R-22: replace. Putting a new compressor and scarce refrigerant into a system that cannot be recharged economically next time is money spent twice.
- Furnace also past 15 years: a combined replacement at $7,500–$11,500 saves roughly a thousand dollars over doing them separately, as explained in should I replace the furnace and AC together.
One more factor for houses in Burlington, Oakville and Hamilton: a dead compressor is the moment a cold-climate heat pump becomes an option. It replaces the air conditioner outright, heats for most of the winter, and current Ontario programs return up to $7,500 on qualifying installs. The Ontario HVAC rebates guide has the current rules.
What to do while you decide
Turn the system off at the thermostat and leave it off; a compressor that is trying and failing to start draws heavy current and can take the contactor and wiring with it. Run the furnace fan on its own for circulation and keep the blinds down on the west side through the afternoon. Financing through our lending partners is available for a replacement, with no prepayment penalty.
ZK Mechanical quotes compressor replacement and new-system installation side by side, in writing, so you can compare them for your own house. We install and repair air conditioners in Hamilton, Burlington and Oakville; ask for both numbers and we will walk you through them at the kitchen table.