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A central AC installation in Cowlitz County starts from an unusual position: the equipment a contractor sizes and installs will almost certainly never run. Homes in Cowlitz County, WA have essentially no cooling season — no month of the year is warm enough to call for it. Compressors that sit dormant for years develop seal and contactor problems that only show up under load, so the first time a homeowner switches the system on is also the first real test of whether the install was done right. A contractor quoting here has to account for that, sizing the system to a house that generates almost no cooling demand while still commissioning it in a way that will hold through years of inactivity.
Ductwork laid down for one generation of equipment does not automatically carry the next. Half the homes in Cowlitz County, Washington were built in 1976 or earlier (2020-2024 ACS 5-year). That gap between when the house was built and what a contractor puts into it today is where an installation either works cleanly or does not, and it shows up in the ducts before it shows up anywhere else. A contractor assessing a central AC job here checks whether the existing duct runs can move the right volume of air for a modern unit, and whether they are still sealed well enough to be worth keeping. Some are. Some have to be relined, rerouted, or partly replaced before the new equipment can do its job.
What Gets Installed With a New Central AC
The outdoor condenser unit sits on a concrete pad beside the house and holds the compressor and condenser coil, the parts that shed heat outside. Inside, the air handler mounts in a utility space, a closet, or an attic and moves conditioned air through the home. These two units are the core of what a contractor installs.
A copper refrigerant line set runs between the outdoor and indoor units, connecting them through an exterior wall. The thermostat goes on an interior wall where it can read the home's air accurately and give the homeowner a single point of control over the whole system.
The drawing shows a typical layout, and a licensed contractor determines what the installation looks like in your specific home.
Get matched in Cowlitz CountyCowlitz County, by the numbers
14 severe weather events were recorded in Cowlitz 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 Cowlitz County, Washington were built in 1976 or earlier (2020-2024 ACS 5-year).
U.S. Census Bureau, 2020-2024 American Community Survey 5-Year EstimatesCowlitz County, Washington holds 46,422 housing units (2020-2024 ACS 5-year).
U.S. Census Bureau, 2020-2024 American Community Survey 5-Year EstimatesOwners occupy 68.0% of the occupied homes in Cowlitz County, Washington (2020-2024 ACS 5-year).
U.S. Census Bureau, 2020-2024 American Community Survey 5-Year EstimatesRules & Standards for Central AC Installation in Cowlitz County, Washington9 sourced rules and standards
What the contractor does on installation day
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 Cowlitz County and Washington Require for HVAC Installation
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.