How we grade heat pumps
Every zip page shows one of four verdicts — NO BRAINER, SOLID YES, WORTH A LOOK, or NOT YET. We compute that tier from three measurable factors and five federal data sources. The math lives here. If a grade surprises you, this page tells you why.
Three dials, one weighted sum
1. Payback speed — 50% weight
How many years of operating savings does it take to repay the net out-of-pocket install cost (after every stackable rebate). We assume the most common scenario: replacing an 18-year gas furnace and a 15-year AC at the same time — so the “install” is the incremental cost over doing those two replacements separately, not the full heat pump sticker price.
Bounds: 0 to 20 years, lower-better. A 7-year payback scores 65/100. A 20-year payback scores 0.
2. Climate fit — 30% weight
Winter 99% design temperature — defined by ASHRAE, published in the NOAA 1991-2020 Climate Normals. This is the temperature your home will see for roughly 1% of winter hours. Cold-climate-certified NEEP-listed heat pumps are rated down to about -15°F; below that you need dual-fuel or backup resistance strips.
Bounds: -40°F to 60°F, higher-better. Atlanta at 22°F scores 62/100. Minneapolis at -4°F scores 36.
3. Rebate stack — 20% weight
Percentage of the gross install delta covered by stackable incentives:
- IRS §25C Federal Tax Credit — 30% of qualifying equipment cost, capped at $2,000 per year.
- State programs — from DSIRE, covering HEAR rollouts, Mass Save, NYSERDA Clean Heat, Energy Trust of Oregon, Minnesota CIP, Colorado Energy Office, etc.
- Utility rebates — Xcel, APS, PGE, ConEd, Eversource, Georgia Power, and others per DSIRE.
Bounds: 0% to 100% of install. 60%+ stacked is “Loaded”, 35-60% is “Standard”, below 35% is “Light”.
Weighted sum, in public
paybackScore = normalize(paybackYears, [0, 20], lower-better)
climateScore = normalize(designTempF, [-40, 60], higher-better)
rebateScore = normalize(rebateCoveragePct, [0, 100], higher-better)
HeatPumpScore = 0.5 × paybackScore
+ 0.3 × climateScore
+ 0.2 × rebateScore
tier = NOT YET when HeatPumpScore ∈ [0, 44]
| WORTH A LOOK when HeatPumpScore ∈ [45, 64]
| SOLID YES when HeatPumpScore ∈ [65, 84]
| NO BRAINER when HeatPumpScore ∈ [85, 100]Two overrides force NOT YET
Regardless of the weighted sum, two situations push the verdict to NOT YET:
- Winter design temp below -15°F and no NEEP-listed cold-climate model commercially available. Below this line, a single-stage air-source heat pump cannot hold setpoint alone; you need dual-fuel or backup strips, which change the economics fundamentally.
- Computed payback beyond 18 years. That's longer than most heat pump equipment lasts (15-year median life), so you'd be replacing the unit before breaking even.
Minneapolis, MN 55410
Minneapolis is an honest case — generous rebates (federal + Minnesota CIP + Xcel utility) but a brutal -4°F design temp and only modest annual savings. The math:
| Factor | Value | Normalized | Weight | Contribution |
|---|---|---|---|---|
| Payback | 33.1 yr | 0/100 | ×0.5 | +0.0 |
| Climate | -7°F | 33/100 | ×0.3 | +9.9 |
| Rebate | 55% | 55/100 | ×0.2 | +11.0 |
| Total | 21/100 | |||
Tier: NOT YET. Not bad, not great — the rebate stack is generous but cold-climate ops costs and modest annual savings cap the payback. See the full zip page →
What the score is not
- Not a quote. Contractors in your area can come in 30% above or below the reference install cost.
- Not tuned to your specific home. Insulation, ductwork condition, occupancy patterns, and existing heat source all shift payback.
- Not a regulatory recommendation. Heat pump replacement is a private capital decision; we score the economics, not the politics.
Where the data comes from
- EIA Open Data — retail electricity + natural gas prices by state and utility
- NOAA 1991-2020 Climate Normals — HDD, CDD, winter design temperatures
- DOE Building America Solution Center — residential heat pump performance by IECC zone
- DSIRE — state and utility-level incentive programs
- ENERGY STAR Qualified Products — certified heat pump models and cold-climate capability
Methodology v1 — 2026-04. Next revision when HEAR rollouts reach 40+ states or when a major EIA rate category shifts by 15%+. Every zip page shows its exact data vintage.