AC contactor replacement cost
Replacing the contactor in your outdoor AC unit costs $200 to $450 with a technician. The part itself costs only $20 to $100. A failing contactor is a common reason an AC won't start or keeps running when it should shut off.
Quick answer
$200 – $450parts and labor
Most contactor replacements cost $200 to $450. If it's swapped during a tune-up or another repair, it can cost about $150.
Contactor and related electrical repairs
| Repair | Cost |
|---|---|
| Contactor | $200 – $450 |
| Capacitor | $100 – $400 |
| Relay switch | $100 – $300 |
| Fuse or breaker | $75 – $300 |
| Disconnect box | $150 – $500 |
| Circuit board | $150 – $700 |
What an AC contactor does
The contactor is an electrical switch in the outdoor unit. When the thermostat calls for cooling, a low-voltage signal pulls the contactor closed, sending power to the compressor and fan. Pitted or burned contacts and insect nests are common failure causes.
Signs of a bad contactor
- Outdoor unit won't start, though the indoor fan runs
- Outdoor unit keeps running when the thermostat is off (stuck contacts)
- Chattering or buzzing from the outdoor unit
- Visible burn marks or melted plastic on the contactor
A stuck contactor can freeze the coil or damage the compressor, so shut off power at the disconnect and call for service.
How to get a fair quote
- Get at least three written quotes that list the brand, model number, size (tons or BTU) and efficiency rating.
- Ask whether the price includes permits, removal of the old unit, refrigerant, a new thermostat and any duct or electrical work.
- Ask for a load calculation (Manual J) instead of matching the old unit's size by default.
- Compare labor warranties (1 to 10 years) as well as the manufacturer's parts warranty, and register the equipment.
- Schedule non-urgent work in spring or fall, when contractors are less busy and more willing to discount.
Frequently asked questions
How much does it cost to replace an AC contactor?
About $200 to $450 with labor; the part is $20 to $100.
How long does an AC contactor last?
Often 10 years or more, but frequent cycling, pitting and pests can shorten its life.
Can a bad contactor damage the compressor?
Yes. Pitted contacts can cause voltage problems, and stuck contacts can keep the compressor running when it should stop.
Sources
Prices are national averages and typical ranges from published cost data. Your price depends on your home, region, equipment and contractor, so get several written quotes. Heat & Air Costs is not an HVAC contractor; read our disclaimer.