Every heat pump proposal you get in Puget Sound has two numbers on it that most homeowners nod at and don't actually understand: SEER2 and HSPF2. They matter. They also get used as a sales lever, because a bigger number looks like a better machine and nobody wants to be the person who bought the cheap one.
Here's the honest version of what those ratings mean, and which of them is worth real money in a marine climate where winter design temperatures across our service area run from 17°F in Olympia to 29°F in Tacoma.
What SEER2 and HSPF2 actually measure
Both are seasonal efficiency ratings. Neither is a peak performance number — they're an estimate of how the system performs across a whole season of varying outdoor temperatures.
SEER2 — the cooling number
SEER2 stands for Seasonal Energy Efficiency Ratio 2. It's cooling output over a season divided by the electricity consumed to produce it. Higher means less power to remove the same heat.
HSPF2 — the heating number
HSPF2 is Heating Seasonal Performance Factor 2. Same idea, other direction: heat delivered over a heating season divided by electricity consumed. This is the number that governs what your heat pump costs to run from October through April.
There's a third rating you'll sometimes see, EER2, which measures cooling efficiency at a single hot design condition rather than across a season. It matters more in Phoenix than it does in Federal Way.
Why the numbers changed in 2023
On January 1, 2023 the Department of Energy switched the industry to the M1 test procedure. The big change: equipment is now tested against higher external static pressure — meaning the test fan has to push air through more resistance, which is a much better stand-in for the duct systems that exist in actual houses.
The result is that the same physical machine earns a lower number under SEER2/HSPF2 than it did under the old SEER/HSPF. Roughly speaking, a SEER2 figure lands about 4 to 5 percent below the old SEER figure for the same equipment. Nothing got worse. The yardstick got more honest.
Which brings up the point most efficiency conversations skip: the rating assumes your ductwork isn't fighting the machine. A high-HSPF2 system connected to crushed, leaky, undersized ducts will not deliver its rated efficiency, and no nameplate can fix that. If your duct system is suspect, that's a ductwork conversation before it's an equipment-tier conversation.
In this climate, HSPF2 is the number that matters
Run the hours. A Puget Sound home calls for heat across roughly seven months of the year. It calls for real cooling for a few weeks in July and August, plus scattered warm days on either side.
So the efficiency number attached to seven months of runtime moves your annual bill far more than the one attached to three weeks. That's not an opinion — it's arithmetic, and it's the opposite of how this equipment gets marketed nationally, where SEER2 is the headline because most of the country buys air conditioning first.
Practical translation for a Western Washington homeowner:
- Prioritize HSPF2 when comparing two systems at similar price.
- Treat SEER2 as a floor, not a target. Mid-teens SEER2 is genuinely fine here.
- Ignore anyone selling you a cooling rating as the main reason to upgrade. In this climate it's a rounding error next to the heating side.
What each tier actually buys you
The efficiency number is mostly a proxy for the technology inside. That's the more useful way to think about it.
| Tier | What's inside | What you actually notice |
|---|---|---|
| TierGood | What's insideSingle-stage compressor, fixed-speed blower | What you actually noticeFull blast or off. Bigger temperature swings, louder cycles, lowest price |
| TierBetter | What's insideTwo-stage compressor, variable-speed blower | What you actually noticeRuns on low most of the time. Steadier temps, quieter, better dehumidification |
| TierBest | What's insideFully variable / inverter-driven compressor | What you actually noticeModulates continuously, holds setpoint tightly, quietest, highest rating |
The biggest real-world jump is from Good to Better. That's where you get long, low-speed runtime instead of hard on-off cycling — and long low-speed runtime is what makes a house feel evenly heated and pulls moisture out of the air during our damp shoulder seasons.
The jump from Better to Best is smaller in dollars saved and larger in comfort refinement. Some homes are worth it. A 1,400 square foot rambler with straightforward ductwork usually isn't.
Ductless is the same story. Mini-split systems are inverter-driven by default, which is part of why they post high ratings, and they run $8,000 to $14,000 installed in standard markets.
Rebates set a floor, and that floor is real
Here's where the numbers stop being academic. Rebate programs specify minimum SEER2 and HSPF2 values that the installed equipment has to meet. Buy under the threshold and the rebate simply doesn't happen — the equipment can be perfectly good and still not qualify.
So the practical rule is: clear the rebate threshold, then decide whether going further up the tier ladder is worth it to you, not to the spec sheet.
Two things worth stating plainly, because they change the math:
- The federal 25C tax credit ended December 31, 2025. No 2026 installation qualifies for it. Anyone still using it to justify an efficiency upgrade is working from an old script.
- From April 2, 2026, PSE rebates require a PSE-certified installer. Varsity is PSE Certified and files the paperwork. Programs change — we confirm your current eligibility before you sign.
And the rebate rule everyone forgets: eligibility follows the meter, not the county. Tacoma, Fircrest, University Place and Fife are Tacoma Power. Seattle is City Light. Gig Harbor and Fox Island are Peninsula Light. Parkland and Spanaway are member-owned mutuals. Burien, Normandy Park, Renton, SeaTac and Tukwila are split by address. Whose name is on your power bill decides which program applies. More detail in our breakdown of PSE heat pump rebates.
Where the efficiency money actually goes
If you gave us a fixed budget and told us to maximize comfort and operating cost in a Puget Sound home, ratings would not be the first line item.
- Correct sizing. An oversized high-efficiency system short-cycles and underperforms a right-sized mid-tier one. Every estimate we write includes a real Manual J load calculation.
- Duct condition. Sealing and repairing what's there protects whatever rating you paid for.
- Tier upgrade — Good to Better. The comfort-per-dollar sweet spot for most homes.
- Top-tier variable speed. Worth it in larger homes, homes with difficult zoning, and homes where quiet operation is a priority.
Ready to see what your house actually needs? Get real numbers in about sixty seconds with our instant estimate tool, or request a free in-home estimate and we'll size it properly.
When paying up for efficiency makes sense
Buy up
- You're replacing electric resistance heat and runtime will be high year-round.
- Larger home, colder pocket — Olympia, Lacey, Tumwater and Yelm sit at a 17°F design temperature, the coldest in our service area.
- You want quiet. Variable-speed equipment loafing at 30 percent is dramatically quieter than a single-stage unit slamming on.
- You're staying in the house 10-plus years.
Don't buy up
- Small, well-insulated home with modest heating load. A percentage of a small number is a small number.
- Ductwork that needs work first — fix the delivery system before buying a fancier source.
- You're selling within a few years. Buyers don't pay a premium for HSPF2.
- The only reason offered is a higher cooling rating. In this climate that's the weakest argument on the page.
What we do on an estimate
We run the load calculation, look at your ducts and electrical, and put Good, Better and Best on one page with the SEER2 and HSPF2 for each and the rebate threshold marked. You see what each step up costs and what it buys. Then you decide — no manufactured urgency, no one-tier-only proposal.
Every installation carries a 10-year parts and labor warranty regardless of which tier you choose, and most installs are done in one day.
Call (253) 785-4622 Monday through Friday, 8 to 6, or book your free estimate online. Federal Way based, owner-operated, and still answering the phone after the check clears.