Thurston County spent decades not needing air conditioning. That argument stopped working around the second week of a 90-degree August, and now roughly half the estimates we run from Olympia to Yelm start with some version of "the winters are fine, the summers are getting unlivable upstairs."
Here are the real 2026 numbers, what actually moves them, and the trade-off most homeowners here don't get told: in a lot of Olympia houses, the smarter buy isn't an air conditioner at all.
The short answer on price
Olympia, Lacey, Tumwater and Yelm are standard-market pricing in our service area — no Bellevue or Gig Harbor premium. Installed, including labor, materials and permit:
| Path | Installed cost | What you get |
|---|---|---|
| PathAdd central AC to existing furnace | Installed cost$5,000 – $12,000 | What you getCooling only, reuses your furnace and ducts |
| PathReplace furnace and AC together | Installed cost$10,000 – $16,000 | What you getNew heating and new cooling, two pieces of equipment |
| PathDucted heat pump | Installed cost$12,000 – $18,000 | What you getHeating and cooling in one system, rebate-eligible |
| PathDuctless mini-split | Installed cost$8,000 – $14,000 | What you getZone-by-zone cooling and heating, no ducts required |
| PathDuctwork repair or replacement | Installed cost$3,000 – $8,000 | What you getOnly if the ducts can't carry the airflow |
That $5,000-to-$12,000 range on add-on AC is wide for a reason, and anyone who quotes you a flat number over the phone is guessing. A 1,400-square-foot rambler off Boulevard Road with a three-year-old furnace, an unused 240V circuit in the panel, and a condenser location ten feet from the air handler lands near the bottom. A 2,600-square-foot two-story on the Westside with a full panel, a long line set run and marginal return air lands near the top.
Why Olympia's housing stock changes the quote
1980s–1990s ramblers and split-levels
This is the easiest and most common job in Thurston County. Gas furnace in the garage or a hall closet, ductwork already in the crawlspace, plenty of yard for a condenser pad. If the furnace blower is variable-speed or at least multi-speed, adding cooling is mostly a matter of matching an evaporator coil to the airflow and running a line set. One day, permit pulled, done.
South Capitol, Bigelow and the older core
Historic-district and pre-war homes are the opposite story. Many have no ducts at all, or have a converted gravity system that was never designed to move cooling air. Retrofitting ducts into a finished 1920s house is invasive and expensive, which is why ductless mini-splits at $8,000 to $14,000 usually beat forcing central AC into a home that doesn't want it. Olympia also has additional review requirements for exterior equipment placement in historic areas — we handle that as part of the permit.
Electric-baseboard and wall-heater homes
If your house is heated by electric resistance, you don't have a furnace or ducts to bolt an air conditioner onto. Your cooling path is a mini-split or a full ducted heat pump system, and the upside is real: converting off electric resistance is the classic case where a local utility rebate comes into play, and heat pumps cut heating costs 30 to 50 percent versus baseboards.
Manufactured homes
Common around Yelm and rural Thurston County. Duct systems in manufactured homes are often undersized belly ducts that struggle with cooling airflow. These are absolutely doable, but the duct assessment isn't optional and the answer is sometimes ductless.
What actually moves the price
- Tonnage and load. Every quote we write includes a Manual J load calculation at no extra cost. Square footage alone doesn't size a system — insulation, window area and orientation, ceiling height and layout all move the number. Oversized cooling short-cycles, leaves the house clammy, and wears out early.
- Ductwork condition. Cooling pushes more air than heating. Leaky, crushed or under-returned duct in a damp Thurston crawlspace is the single most common reason a brand-new system disappoints. Repairs are often modest; a full replacement is $3,000 to $8,000.
- Electrical. A condenser needs a dedicated 240V circuit and a disconnect. Homes with room in the panel are cheap; a full or antique panel means coordinating a licensed electrician.
- Equipment tier. Good, Better, Best is a real fork, not a sales script. Higher SEER2 ratings, two-stage and variable-speed compressors cost more up front, run quieter, and dehumidify better — which matters more in our muggy late-summer stretch than most people expect.
- Site conditions. Line set length, pad location, drainage, and how far the condenser sits from bedroom windows and the neighbor's fence.
Standalone AC vs. a heat pump — the honest math
This is the conversation worth having in Olympia specifically.
A standalone air conditioner cools. That's it. It rides on your existing furnace, which means when that furnace dies in four years you pay again — and the new equipment has to be matched to it.
A ducted heat pump is an air conditioner that also runs backwards in winter. Same outdoor unit footprint, same ducts, same one-day install in most homes. It costs $12,000 to $18,000 here versus $5,000 to $12,000 for cooling-only, but it replaces the furnace's job too, and it is the only path on the table that can qualify for a local utility rebate. Standalone AC generally does not.
When does standalone AC still win? When your furnace is genuinely young and healthy, when the budget has a hard ceiling this summer, or when you specifically want to keep gas heat. We say so on estimates. It costs us bigger jobs and it's still the right answer sometimes.
One Olympia-specific wrinkle worth knowing: Washington's energy code lists a 17°F winter design temperature for Olympia, Tumwater, Lacey and Yelm — the coldest in our entire 45-city service area, twelve degrees below Tacoma. That doesn't make heat pumps a bad idea here; 17°F is still well inside the range where modern equipment delivers full output. It does mean the sizing and the backup-heat strategy need to be done properly rather than eyeballed off a neighbor's system.
About rebates, plainly
Local utility rebates may apply to a qualifying heat pump installation. The amount depends on what is being replaced and the efficiency of the equipment installed — converting from electric resistance is treated very differently from a like-for-like swap. Programs change, and utilities pay only through their own contractor networks, so we confirm what your utility actually pays before quoting it, then file the paperwork as part of the job. If you want the longer version, read our Washington heat pump rebate breakdown.
And to kill the most persistent myth: the federal 25C tax credit ended December 31, 2025. No 2026 installation qualifies. Any bid that still lists it is working from an old spreadsheet.
Ready for a real number?
Answer seven questions and see Good, Better and Best starting prices in about a minute with our instant estimate tool — or book a free in-home visit through Get an Estimate and we'll run the load calculation, look at your ducts and panel, and put three written options in front of you.
Call (253) 785-4622 Monday through Friday, 8 to 6. Every installation carries a 10-year parts and labor warranty, the permit is pulled on every job, and most systems go in in a single day.
We're heat pump and cooling specialists based in Federal Way, working Thurston County every week. Not the cheapest bid — the one done right by people who answer the phone after the check clears.