Cold-Climate Heat Pumps for Washington Winters
Heat pumps built to keep heating in a Washington cold snap, sized to your home’s design temperature with a room-by-room load calculation.
Locally-owned since 1977 • Licensed, bonded and insured in Washington (WA Contractor Reg. #HOMECCA785BD) • WA Electrical Contractor Lic. #HOMECCA782DC • NATE-certified technicians • Mitsubishi Electric Diamond Dealer • Lennox Premier Dealer
What is a cold-climate heat pump?
A cold-climate heat pump is an air-source heat pump that keeps most of its heating output and efficiency in freezing weather. ENERGY STAR's Cold Climate label requires a COP of at least 1.75 at 5°F and at least 70% of its rated heating capacity at 5°F. Home Comfort Alliance installs cold-climate ducted heat pumps and ductless mini-splits across Western Washington, sized with a room-by-room load calculation (ACCA Manual J).
We've heated Washington homes since 1977, our technicians are NATE-certified, and we're a Mitsubishi Electric Diamond Dealer, a Carrier Factory Authorized Dealer and a Lennox Premier Dealer. This page covers what the cold-climate label means, how cold it really gets where you live, and when the upgrade pays off. For heat pump basics, types and costs in general, start with our heat pump installation guide.
How does a heat pump earn the cold-climate label?
A heat pump earns the label by passing a test at 5°F, not by its name or marketing. Three specifications matter in Washington, and they measure the same thing in slightly different ways:
| Label | Who sets it | What it tests | Where to check |
|---|---|---|---|
| ENERGY STAR Cold Climate | U.S. EPA | COP of at least 1.75 and at least 70% of rated heating capacity at 5°F; HSPF2 of 8.5 or more (ductless) or 8.1 or more (ducted); SEER2 of 15.2 or more; the unit's own controls are verified | ENERGY STAR product finder |
| NEEP cold-climate air-source heat pump list (v4.0) | Northeast Energy Efficiency Partnerships | COP above 1.75 at 5°F, with published capacity and efficiency at 47°F, 17°F and 5°F. Version 4.0 took effect January 2023; version 5.0 is pending | NEEP list; BPA's Northwest programs use it |
| NEEA cold-climate ductless spec (v2.0) | Northwest Energy Efficiency Alliance | Inverter-driven, matched ductless system keeping at least 80% of capacity at 5°F with a COP of at least 1.75 | Used by Northwest utility programs |
COP (coefficient of performance) is heat delivered per unit of electricity. A COP of 1.75 at 5°F means the heat pump delivers 1.75 units of heat for every unit of electricity it uses, even on a very cold night. Electric baseboard always delivers 1. Capacity retention tells you how much of its rated output the unit still has when it's cold, which decides whether it can carry the house alone.
Sources: ENERGY STAR key product criteria, NEEP ccASHP specification and NEEA Cold Climate DHP Spec v2.0 (August 2022), all checked October 2026.
How cold does it get where you live?
Most Puget Sound lowland homes have a code design temperature in the 20s, well inside a modern heat pump's range. The design temperature is the cold-night figure heating systems are sized to, and Seattle's energy code lists it by weather station:
| Weather station | Energy code design temperature |
|---|---|
| SeaTac (Seattle) | 24°F |
| Bellevue | 24°F |
| Tacoma | 29°F |
| Bremerton | 29°F |
| Everett (Paine Field) | 21°F |
| Olympia | 17°F |
| Snoqualmie Pass | 6°F |
Source: 2021 Seattle Energy Code, Appendix C, Table C-1 (checked October 2026). Towns not listed, such as Mount Vernon, Monroe, Duvall, North Bend, Enumclaw and Buckley, are sized from the nearest station or local data at your estimate.
The Northwest Energy Efficiency Alliance treats homes east of the Cascades and "higher-elevation areas west of the Cascades" as cold climate. Homes in lower areas that still see nights near or below 5°F count too. So the answer changes with your elevation and exposure, not just your city.
Who should choose a cold-climate model
- All-electric homes with no furnace behind the heat pump.
- Homes leaving electric baseboard, an oil furnace or an electric furnace for good.
- Foothill and higher homes, such as the Snoqualmie Valley or the Enumclaw plateau, and windy, open sites.
- Anyone using PSE's heat pump to heat pump upgrade rebate, which requires a cold-climate unit.
A standard variable-speed heat pump with backup heat suits many lowland homes; we'll show you both options and the trade-offs at your estimate.
What happens to a heat pump as it gets colder?
Every air-source heat pump loses some output and efficiency as the outdoor air gets colder; a cold-climate model simply loses far less of both. The home needs the most heat exactly when the outdoor air has the least to give, so the gap between the two is what backup heat has to fill.
Why variable speed matters
An inverter (variable-speed) compressor speeds up as the temperature drops instead of running at one fixed speed, so it keeps up longer before backup heat starts. It also slows down on mild days, which is most of a Puget Sound winter, and that's where much of the saving comes from. Utility rules point the same way: PSE's ductless rebate for leaving resistance heat requires a variable-speed inverter system, and Tacoma Power's top rebate tiers are for variable-speed heat pumps.
Can ductless heat a whole house in winter?
Often, yes, if the load calculation says the heads can cover each room on a design-temperature night. Open floor plans suit it; closed-off bedrooms may need their own heads or a ducted unit. See our ductless mini-split page and our Quilt ductless option.
The savings are real. The Department of Energy cites a NEEP study finding that an air-source heat pump saves about 3,000 kWh, or $459, a year compared with electric resistance heat, and its 2017 cold-climate article says these systems "can reduce household energy consumption by up to 40%". If you heat with baseboard now, see electric baseboard to heat pump.
Which cold-climate models do the brands we install offer?
All three manufacturers we hold dealer status with make cold-climate or variable-capacity heat pumps; these are each maker's own claims, not our test results:
| Brand and line | Manufacturer's low-temperature claim | Source |
|---|---|---|
| Mitsubishi Electric Hyper-Heating (H2i) | 100% of rated heating capacity down to 5°F; H2i plus holds 100% to -5°F on select systems; operation guaranteed down to -13°F | Mitsubishi Electric, September 2024 |
| Carrier Infinity variable-speed heat pump with Greenspeed Intelligence | 100% of rated capacity at 5°F; ran down to -13°F in field trials and -23°F in the lab | Carrier, September 2024 |
| Lennox SL25XPV | Variable capacity, up to 23 SEER2 and 10.3 HSPF2, R-454B refrigerant; no low-temperature figure published | Lennox, 2022 |
Home Comfort Alliance is a Mitsubishi Electric Diamond Dealer, a Carrier Factory Authorized Dealer and a Lennox Premier Dealer, and a Quilt dealer, and we service all major brands. Seattle's Clean Heat oil conversion rebate requires a qualified Mitsubishi Electric heat pump. Ask us whether a model is ENERGY STAR Cold Climate or NEEP listed before you sign; we'll show you its rating at 5°F.
Sources: Mitsubishi Electric (September 2024), Carrier news release on the DOE Cold Climate Heat Pump Challenge (12 September 2024), Lennox SL25XPV product page (2022).
Do you still need backup heat, and what about defrost?
Most cold-climate installs still have backup heat, but on a well-sized system it should rarely run. Here's how the coldest nights work.
Electric backup (aux) heat
Most ducted heat pumps include electric strip heat in the air handler. It should be set to lock out until it's cold outside; PSE's rebate rules recommend a lockout of 35°F or below. "Emergency heat" is a thermostat setting that runs the strips alone, for when the heat pump itself has a fault; if you're using it, book a heat pump repair. Strip heat draws a lot of power, so our electricians check the circuits and panel (WA Electrical Contractor Lic. #HOMECCA782DC); see electrical panel upgrades and panel upgrades for heat pumps.
Keeping a gas furnace as backup
If you have a working gas furnace, you can keep it as backup and let the heat pump do most of the heating. That's a different setup with different rebates, and we'll price it beside an all-electric cold-climate system at your estimate. Our furnace vs heat pump vs hybrid guide compares them, and gas to heat pump conversion covers leaving gas entirely. Our dual fuel heating page covers the furnace-backup setup in full.
Defrost is normal
In damp weather near freezing, frost builds on the outdoor coil. The heat pump pauses, reverses briefly to melt it, and you may see steam rising from the unit; the DOE notes that demand-defrost controls run this only when needed. Ice that keeps building or a unit that stops heating is a repair. Our phones are answered and bookings are accepted 24/7. Heating and cooling technicians work during business hours and are available after hours for qualifying emergencies ($330 after-hours fee). See emergency heat pump repair.
Where should the outdoor unit go in a cold climate?
The outdoor unit should sit where wind, roof runoff and snow can't bury or ice it. Based on NEEA's cold-climate guidance and the DOE, we look for a spot that is:
- Out of strong prevailing wind, which steals heat and speeds frosting.
- Not under a roof edge or gutter that drips onto the coil.
- Away from where snow drifts or slides off the roof.
- Raised on a stand or snow legs tall enough for the snow your area gets.
- Placed so defrost meltwater drains away from walkways and steps, where it can refreeze.
- Away from bedroom windows, with service clearance on every side.
In winter, don't cover the unit while it runs and don't chip ice off the coil; keep snow and leaves clear around it instead. More tips in how to winterize a heat pump. Seattle also limits heat pump noise at the property line, which affects placement on tight lots; see heat pumps in Seattle.
Which rebates require a cold-climate heat pump? (checked October 2026)
Only one Washington rebate we checked requires a cold-climate unit: PSE's heat pump to heat pump upgrade. The others set efficiency or variable-speed rules instead, so a cold-climate model qualifies but isn't required.
| Program | Requires cold-climate? | Key rule | Amount |
|---|---|---|---|
| PSE heat pump to heat pump upgrade | Yes | New unit COP of at least 1.75 and at least 70% of rated capacity at 5°F; replaces an existing ducted, all-electric heat pump out of its original warranty; electric aux heat locked out (35°F or below recommended); not ductless or dual fuel | $1,500, plus $2,400 Efficiency Boost if income-qualified |
| PSE electric resistance to heat pump | No | Ducted all-electric, or ductless variable-speed inverter of at least ¾ ton; no dual fuel | $1,500, plus $2,400 Efficiency Boost if income-qualified |
| Tacoma Power | No | HSPF2 7.5 and SEER2 14.3; top tiers for variable-speed systems | $1,000 to $2,000 |
| Seattle City Light | No | Tiers by HSPF2 (8.1, 8.5, 9.5) and SEER2, under 5.4 tons | $300, $400 or $600 |
| Snohomish PUD | No | 7.5 HSPF2 ducted; inverter-driven tier needs 8.5 HSPF2; electric primary heat | $1,800 or $2,500 |
| Energy Smart Eastside | Approved equipment list | Whole-home sizing; six Eastside cities | $1,000 instant (applied at the point of sale), plus up to $5,000 bonus if income-qualified and all-electric |
| Seattle Clean Heat | Mitsubishi Electric required | Oil-heated Seattle homes; oil tank decommissioned to Seattle Fire Department rules by a certified decommissioner | $2,000, plus $4,000 bonus (81% to 150% AMI) through 30 May 2027 |
| Federal 25C tax credit | n/a | Ended for equipment placed in service after December 31, 2025 | None |
We handle the rebate paperwork for you on PSE, Tacoma Power and Cascade rebates. Home Comfort Alliance is a PSE Trade Ally, an approved contractor with Tacoma Power, Seattle City Light, Snohomish PUD and Energy Smart Eastside, and a participating contractor in the City of Seattle's Clean Heat Program. We don't remove or decommission oil tanks. Moving off oil? See oil to heat pump conversion.
Rebates change. We confirm amounts with your utility before you sign. Sources: PSE, Tacoma Power, Seattle City Light, Snohomish PUD, Energy Smart Eastside and City of Seattle program pages (checked October 2026). More on our rebates, PSE rebates and Energy Smart Eastside rebates pages.
What does a cold-climate heat pump cost?
Expect to pay more than for a standard heat pump: Angi's national estimate is "$2,000 to $5,000 more for a heat pump system designed to handle freezing temperatures" (August 2026). That is a national estimate, not a Home Comfort Alliance price.
Your price depends on your home's heating and cooling needs, the add-ons you need, how many rooms the system serves and where it's installed. For cold-climate systems the big drivers are the size needed at your design temperature, ducted or ductless, the brand and line, an air handler or coil, refrigerant lines, a stand or snow legs, strip heat circuits or a panel upgrade, and permits. Get a price range in about 30 seconds with our free instant quote tool, then a technician confirms the exact price on a free site visit. Installed price ranges and the full rebate list are in our heat pump cost guide.
Financing
Low monthly payment plans starting at $179/month* through Salal Credit Union or Synchrony, with 0% interest options for qualifying customers and instant online approval. See financing.
*Financing through Salal Credit Union or Synchrony, subject to credit approval. Rates, terms and monthly payments depend on the amount financed, the plan and your credit. 0% interest options are available to qualifying customers. See lender for full terms.
Get a free estimateAn in-home visit and a written, upfront price before any work begins.
How do we size and install a cold-climate heat pump?
We size the system to your home's heat loss on a design-temperature night, then install it so it can deliver that heat. The steps:
- Try the instant quote tool, or book your free in-home estimate.
- A room-by-room load calculation (ACCA Manual J) on every installation, using your area's design temperature.
- We match equipment whose heating output at that temperature covers the load, and check ducts, the outdoor spot and the electrical panel.
- You get a written, upfront price and a rebate check for your utility. Upfront, transparent pricing before any work begins.
- We pull the required permits for every installation.
- Our crew installs the system, the stand or pad, the controls and the backup heat settings, and tests it.
- We file the PSE, Tacoma Power or Cascade rebate paperwork and walk you through the thermostat, defrost and winter care.
Replacing an older heat pump? See heat pump replacement. Yearly heat pump maintenance keeps your labor warranty active.
A recent heat pump installation in North Bend
In September 2026 our install crew put a Quilt ductless heat pump system into a North Bend home in the Snoqualmie Valley. The old equipment came out and was disposed of, and the new system was tied into the home's existing electrical panel with its own disconnect.
The crew ran a new refrigerant line set with an exterior cover, set the outdoor unit on a pad and added a condensate drain. As with every new system we install, first-year maintenance is included.
What you get with Home Comfort Alliance
- NATE-certified technicians and a room-by-room load calculation (ACCA Manual J) on every installation
- Licensed, bonded and insured in Washington (WA Contractor Reg. #HOMECCA785BD; WA Electrical Contractor Lic. #HOMECCA782DC)
- Mitsubishi Electric Diamond Dealer, Carrier Factory Authorized Dealer and Lennox Premier Dealer; we service all major brands
- Lennox Centurion Award 2024 and 2025; Gensco Ducted, Ductless and Multi-Zone Excellence 2024 to 2025
- PSE Trade Ally; approved contractor with Tacoma Power, Seattle City Light, Snohomish PUD and Energy Smart Eastside; a participating contractor in the City of Seattle's Clean Heat Program
- 3-year Comfort Shield labor warranty on new installations, kept active with yearly maintenance. First-year maintenance is included. We support the manufacturer's warranty on covered parts.
- Home Comfort Club members with a new system installed by Home Comfort Alliance get extended labor coverage for up to 5 years from installation. See Home Comfort Club.
- Upfront, transparent pricing before any work begins
- Locally owned since 1977; BBB Accredited Business since 2002; Best Pick 2025 and 2026; 4.8 stars from 5,000+ reviews
Where do we install cold-climate heat pumps?
We install cold-climate heat pumps across King, Pierce, Snohomish, Kitsap and Skagit counties, from walk-in offices in Sumner (headquarters), Everett and Bremerton, and from our Redmond service location. Colder spots are where the upgrade matters most: Everett and north into the Skagit Valley, the Snohomish and Snoqualmie river valleys, the Eastside plateau and the foothills toward Buckley.
Cold-climate heat pump FAQ
What is a cold-climate heat pump?
It's an air-source heat pump that keeps most of its heat output in freezing weather. ENERGY STAR's Cold Climate label requires a COP of at least 1.75 and at least 70% of rated heating capacity at 5°F, checked with the unit's own controls.
Do heat pumps work in Seattle winters?
Yes. The energy code design temperature for Seattle (SeaTac) is 24°F, and most modern variable-speed heat pumps keep heating well below that. A cold-climate model holds more of its output on the coldest nights, so backup heat runs less.
Do I need a cold-climate heat pump in the Puget Sound area?
Not always. Many lowland homes do fine with a standard variable-speed heat pump and backup heat. We recommend a cold-climate model for all-electric homes, homes in the foothills or higher elevations, windy open sites, and anyone using PSE's heat pump to heat pump upgrade rebate.
At what temperature does a heat pump stop working?
It depends on the model. Mitsubishi Electric says its Hyper-Heating systems operate down to -13°F, and Carrier reports its Infinity Greenspeed heat pumps ran down to -13°F in field trials. Standard heat pumps lose output sooner, which is when backup heat helps.
What's the difference between ENERGY STAR Cold Climate and the NEEP list?
Both flag heat pumps that heat well at 5°F. ENERGY STAR's Cold Climate label sets minimum COP, capacity and efficiency ratings. NEEP's cold-climate list publishes each model's performance at 47°F, 17°F and 5°F, and Northwest programs such as BPA's use it.
Is a Mitsubishi Hyper-Heat worth it in Washington?
It makes the most sense where winters bite: all-electric homes, foothill towns, or rooms far from other heat. Mitsubishi rates Hyper-Heating systems at 100% of capacity down to 5°F. Home Comfort Alliance is a Mitsubishi Electric Diamond Dealer, and Seattle's Clean Heat oil conversion rebate requires a Mitsubishi Electric heat pump.
Do I still need backup heat with a cold-climate heat pump?
Usually you'll have it, but it should rarely run. Most ducted systems include electric backup strips, set to lock out until it's cold outside; PSE recommends a lockout of 35°F or below on its rebates. If you'd rather keep a gas furnace as backup, ask us to price that setup too.
Why does my heat pump stop and steam in cold weather?
That's usually a normal defrost cycle. The outdoor coil collects frost, and the heat pump briefly reverses to melt it. If ice keeps building up or the unit stops heating, call us for a repair.
Should I cover my outdoor unit in winter?
No, not while it's in use. Keep snow, leaves and ice clear around it, and don't chip ice off the coil. A stand or snow legs keep the unit above snow and let defrost water drain away.
How much more does a cold-climate heat pump cost?
Angi's national estimate is $2,000 to $5,000 more for a heat pump system designed for freezing temperatures (August 2026). That isn't our price. Use our instant quote tool for a range, then book a free in-home estimate for an exact, upfront price.
Which Washington rebates require a cold-climate heat pump?
Of the programs we checked in October 2026, only PSE's heat pump to heat pump upgrade does: the new heat pump needs a COP of at least 1.75 at 5°F and at least 70% of its rated capacity at 5°F. Other utility rebates set efficiency or variable-speed rules instead.
How do you size a cold-climate heat pump?
We run a room-by-room load calculation (ACCA Manual J) on every installation, using your area's design temperature, then pick equipment whose output at that temperature covers the load. The estimate is free. Large cold-climate models exist, including bigger ducted sizes, but the load calculation, not the biggest unit available, decides the size.
Sources
- ENERGY STAR, air-source heat pump key product criteria, Cold Climate (checked October 2026)
- NEEP, cold-climate air-source heat pump specification v4.0 and ASHP specification pages (checked October 2026)
- NEEA, Cold Climate Ductless Heat Pump Specification and Recommendations v2.0 (August 2022)
- Bonneville Power Administration, cold-climate heat pump list FAQ (checked October 2026)
- City of Seattle, 2021 Seattle Energy Code Appendix C, Table C-1 (checked October 2026)
- U.S. Department of Energy, Energy Saver: air-source heat pumps (checked October 2026); cold-climate air-source heat pumps article (April 2017)
- Mitsubishi Electric, heat pumps for extreme cold climates (September 2024)
- Carrier, DOE Cold Climate Heat Pump Challenge news release (September 2024)
- Lennox, SL25XPV product page (2022)
- Angi, is a heat pump right for me (August 2026)
- Puget Sound Energy, heat pump to heat pump upgrade rebate and electric resistance to air-source heat pump conversion rebate (checked October 2026)
- Tacoma Power, heat pumps (page updated October 1, 2026)
- Seattle City Light, heating and cooling (checked October 2026)
- Snohomish PUD, heating rebates (page updated July 1, 2026)
- Energy Smart Eastside, rebates (checked October 2026)
- City of Seattle, Clean Heat Program (checked October 2026)
Why Choose Home Comfort Alliance for Cold-Climate Heat Pumps?
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Outstanding service, communication, and follow-up, so your home is comfortable now and for years to come.
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