A compressor is the pump in the outdoor unit of an air conditioner or heat pump that pressurizes refrigerant vapor, raising its temperature so heat can be released outdoors. Most residential systems use scroll compressors; single-stage models always run at full output, while two-stage and inverter-driven variable-speed models adjust output to match the load.
Why it matters to you
The compressor is usually the most expensive single part in a cooling system, and its failure often prompts a repair-or-replace decision on older equipment. HVAC repairs are covered only on the Whole Home Repair plan, up to the $3,000 HVAC repair limit.
Practical guidance
Hard starts, clicking at startup or a humming outdoor unit with a still fan often point to a failing capacitor or contactor rather than the compressor itself, so ask for those to be tested first. Keep the outdoor coil clean, since the high pressures a dirty coil causes shorten compressor life.