Decisions Cooling West side
Your furnace is fine but you have no AC: AC or heat pump?
Central AC or Heat pump, furnace stays
Compared by the people who run this site. Updated . Rebates and prices checked November 3, 2026.
Add AC or a heat pump? With a furnace that's still fine, a heat pump is worth pricing first on the West side. ENERGY STAR says dual fuel comes at a modest extra cost over an AC system, and you get cooling plus a second way to heat.
The verdict, by situation
If your gas furnace is relatively new, with sound ducts and no cooling
Ask for a heat pump paired with the furnace. ENERGY STAR describes dual fuel as a modest extra cost over an AC system, so have both priced on one bid.
If the bid shows a large gap between AC and heat pump
Plain central AC is defensible. It still cools, the West side's cooling season is short, and the Sea-Tac normals show 3.8 days a year at 90F or higher.
If your furnace is near the end of its life too
Decide both at once. Read gas furnace or heat pump, because a rebate may hinge on the furnace going away.
If you have no ducts, or only one hot room
Skip both for now. Look at window AC or ductless or one cool room or the whole house.
If someone in the house can't safely ride out a heat wave
Don't wait for a whole-house job. Get cooling into one room this summer, and keep a plan to leave. DOH says dial 2-1-1 for cooling centers.
Side by side
| Compare | Central AC | Heat pump, furnace stays |
|---|---|---|
| Summer cooling | Yes | Yes |
| Winter heat | No, furnace only | Yes, with the furnace as back-up |
| Federal minimum, split system | 13.4 SEER2 | 14.3 SEER2, 7.5 HSPF2 |
| Extra cost compared with AC | Baseline | ENERGY STAR: "modest"; no dollar figure |
| Discounts found | None found for AC | PSE, City Light, Tacoma lines below |
| Noise, Seattle | 45-decibel limit named for heat pumps only | 45 decibels at the property line |
| Smoke with central fan | MERV 13, fan On | Same |
Sources: 10 CFR 430.32, EPA on smoke, Seattle SDCI. The table leaves out the changeover temperature between heat pump and furnace, because we found no West side source for one. Ask the bidder what it's set to, and why.
What would change the answer
- Your furnace is older than ENERGY STAR's 15-year prompt. The bigger decision is then the furnace itself.
- Your ducts leak. ENERGY STAR says about 20 to 30 percent of air can be lost, and that loss applies to cooling too, so read seal or replace the ducts.
- Your bid's price gap is large. "Modest" is ENERGY STAR's word, and your bid is the real number.
- A new code passes. A proposed 2024 code change would encourage heat pumps when air conditioners are replaced, but it isn't law.
- You're east of the Cascades. Yakima's 40.2 days at 90F or higher make a different problem, covered on AC or heat pump when the AC dies.
What it costs, with dates
Written bids are the only price we can point you to, because no official installed-price figure for either option turned up. Ask each one to separate the outdoor unit, coil, thermostat and controls, refrigerant work, electrical, ductwork and permits. Have AC and heat pump priced on the same page.
Discounts, as of November 2026, mostly apply to the heat pump. PSE electric customers had a distributor discount totaling $300 to $600, with part going to the distributor or contractor (archived copy, June 2026); confirm with the utility. Seattle City Light lists $300 to $600 instantly through participating distributors. Tacoma Power lists $1,000 for variable speed from non-electric heat.
PSE's $4,000 income-qualified rebate (archived copy, May 2026) requires replacing gas and removing or decommissioning the old equipment, so it doesn't fit a furnace that stays; confirm with the utility. Federal credits ended for anything installed after 2025. We found no AC rebate at any utility we checked.
Who does the work
This is licensed trade work from start to finish. Both options use refrigerant, which means certified technicians under EPA Section 608. Seattle's permit guide says a refrigeration permit applies to any split system heat pump or air conditioner, and unincorporated King County lists air conditioners among systems needing a permit. Check the firm with L&I. You can change filters, clear plants away from the outdoor unit, and check a breaker. See the West side list for the rest.
Is cooling really worth it on the West side?
Most years it's about comfort, and 2021 showed it can be about survival. Sea-Tac's normal July high is 77.4F. But Sea-Tac hit 108F on June 28, 2021, after 104F the day before.
DOH counts 157 heat-related deaths reported statewide from June 26 to August 31 that year. EIA's 2020 housing survey found 53% of Washington homes use air conditioning, with 30% on central systems.
Signs of heat stroke include confusion, slurred speech, fainting and a body temperature above 103F. NWS says call 911 or get the person to a hospital immediately.
How should a heat pump and a furnace share the job?
A control decides which one runs, so ask how yours is set. ENERGY STAR advises keeping a steady setpoint and avoiding Auto mode on heat pumps.
Have the installer explain the changeover setting and show how to read the thermostat. Size matters as well: DOE's guide asks for Manual J and warns that oversizing can bring poor comfort and mold. The comparison between the two fuels is on the dual-fuel page, and the running-cost page has the arithmetic.
Parts and examples
The site centralplumbinghvac.com shares an owner with this site. It's a heating and cooling service company in Bucks and Montgomery Counties, Pennsylvania, not in Washington, and it can't do this work here. Its air conditioning service page is shown only as an example of how a pro's service page lays out the work.
What people ask next
Can a heat pump be added without replacing my working gas furnace?
ENERGY STAR describes that setup as dual fuel, if the furnace is relatively new. Whether your furnace and ducts can take it is a contractor's call after a load calculation.
Will running central AC clean the air during wildfire smoke?
Only while air moves across the filter. EPA says to run the fan all the time, or the air is cleaned only while cooling, and to use MERV 13 if your system allows.
How much power does West side cooling use?
The one metered figure is ductless: Puget Sound pilot homes used 72 kWh a year for cooling in 2008-09. That's small, but it was before recent heat waves, and it isn't a central system.
Decide next
New gas furnace or heat pump on the West side?
- New gas furnace
- Furnace has failed, cooling isn't wanted, and budget is tight
- Heat pump
- Cooling matters, or an income-qualified PSE gas rebate is on the table
Dual fuel or all electric: which heat pump setup fits your house?
- Dual fuel (heat pump plus furnace)
- Houses with a gas furnace that is still relatively new
- All electric (heat pump plus electric back-up)
- Houses with no gas, or a furnace at the end of its life
Window AC or a ductless heat pump for your house?
- Window AC
- One or two rooms, a small budget, cooling only
- Ductless heat pump
- Electric heat you also want to cut, a long stay
Where this came from
- ENERGY STAR: Air-source heat pumps, checked November 3, 2026.
- ENERGY STAR: When to replace, checked November 3, 2026.
- ENERGY STAR: Duct sealing, checked November 3, 2026.
- NOAA: 1991-2020 annual normals, Sea-Tac, checked November 3, 2026.
- NOAA: 1991-2020 monthly normals, Sea-Tac, checked November 3, 2026.
- NOAA: 1991-2020 annual normals, Yakima, checked November 3, 2026.
- NWS: NOWData, Seattle area, checked November 3, 2026.
- NWS: Heat illness, checked November 3, 2026.
- DOH: Extreme heat, checked November 3, 2026.
- DOH: Excess deaths report, heat dome, checked November 3, 2026.
- EIA: RECS 2020 state air conditioning, checked November 3, 2026.
- EPA: Wildfires and indoor air quality, checked November 3, 2026.
- EPA: Heat and smoke guidance, checked November 3, 2026.
- EPA: Section 608 technician certification, checked November 3, 2026.
- DOE: Home heating and cooling consumer guide, checked November 3, 2026.
- Cornell LII: 10 CFR 430.32, checked November 3, 2026.
- Washington State Register: WSR 26-14-101, checked November 3, 2026.
- PSE: Midstream discount (archived copy, June 2026), checked November 3, 2026.
- PSE: Gas to heat pump rebate (archived copy, May 2026), checked November 3, 2026.
- Seattle City Light: Home energy solutions, checked November 3, 2026.
- Tacoma Power: Heat pump rebates, checked November 3, 2026.
- IRS: FAQs on section 25C and 25D changes, checked November 3, 2026.
- Seattle SDCI: Furnace and heat pump permit guide, checked November 3, 2026.
- King County: Residential mechanical permits, checked November 3, 2026.
- L&I: Verify a contractor, checked November 3, 2026.