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Central AC in King County spends almost all of its life off. Homes in King County, WA have essentially no cooling season — no month of the year is warm enough to call for it. A compressor that sits idle through every month of the year corrodes at its electrical contacts, loses capacitor charge retention, and can seize when it finally gets a start signal. The contactor and the run capacitor are the parts a contractor checks first here, because those are the components that fail in storage, not in service. A homeowner who turns the system on for the first time in a warm spell and gets nothing is usually looking at one of those two.
Half the homes in King County, Washington were built in 1983 or earlier (2020-2024 ACS 5-year). Much of that stock has cycled through at least one generation of HVAC equipment since it was built, which means the units a contractor opens today are old enough that certain components, capacitors, contactors, specific motor assemblies, sit at or past their practical lifespan. When a part fails, the question is not always whether to replace it but whether a matching part is still manufactured. A contractor sourcing components for a system this age may find the OEM part discontinued and have to evaluate compatible alternatives, which changes both the repair timeline and what the job costs.
The Parts of a Central AC a Contractor Checks First
The outdoor condenser unit sits outside the house, usually on a concrete pad at ground level, and it is where heat gets shed to the outside air. The compressor lives inside that cabinet and is often the first suspect when the system stops cooling. A failed capacitor or a seized compressor shows up here.
Inside the house, the air handler holds the evaporator coil and the blower that pushes conditioned air through the home. The evaporator coil is a common failure point when refrigerant is low or airflow is restricted. The expansion valve, the refrigerant lines running between the two units, and the thermostat on the wall all factor into what a contractor traces when something is off.
The drawing shows a typical layout, and a licensed contractor determines which components apply to your specific system and situation.
Get matched in King CountyKing County, by the numbers
1 severe weather event was recorded in King County, Washington between 2015 and 2024.
NOAA National Centers for Environmental Information, Storm Events Database, bulk CSV export, events 2015-01-01 through 2024-12-31.Half the homes in King County, Washington were built in 1983 or earlier (2020-2024 ACS 5-year).
U.S. Census Bureau, 2020-2024 American Community Survey 5-Year EstimatesKing County, Washington holds 1,003,284 housing units (2020-2024 ACS 5-year).
U.S. Census Bureau, 2020-2024 American Community Survey 5-Year EstimatesOwners occupy 55.4% of the occupied homes in King County, Washington (2020-2024 ACS 5-year).
U.S. Census Bureau, 2020-2024 American Community Survey 5-Year EstimatesCode & Licensing Record for Central AC Repair in King County, Washington9 sourced rules and standards
What happens once a contractor comes out
Split-system central air conditioners rated below 45,000 Btu/h manufactured on or after January 1, 2023 must meet a federal minimum of 13.4 SEER2.
Split-system central air conditioners rated at or above 45,000 Btu/h manufactured on or after January 1, 2023 must meet a federal minimum of 13.4 SEER2.
Split-system central air conditioners manufactured between January 1, 2015 and December 31, 2022 had to meet 13 SEER, the metric that preceded SEER2.
Single-package central air conditioners manufactured on or after January 1, 2023 must meet a federal minimum of 13.4 SEER2.
Space-constrained central air conditioners manufactured on or after January 1, 2023 must meet a federal minimum of 11.7 SEER2.
Federal efficiency standards for split-system central air conditioners and heat pumps are set on each certified combination of outdoor unit and indoor coil rather than on the outdoor unit alone.
Residential and light commercial air conditioning and heat pump systems assembled in the field, including mini-splits and unitary systems, may not be installed on or after January 1, 2025 using a refrigerant with a global warming potential above 700.
A field-assembled system whose specified components were all manufactured or imported before January 1, 2025 carries no installation compliance date under the refrigerant restrictions and may still be installed.
What King County and Washington Require for HVAC Repair
Washington requires contractor registration rather than an HVAC licence: every contractor must register with the Department of Labor and Industries, and advertising, bidding or working as a contractor without that registration is a gross misdemeanour.