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Proair vs WILLIS heat pumps

Measured against models of the same size and duct type, Proair and WILLIS split the 6 ratings 3–3. Proair has 11 outdoor models, WILLIS has 15 outdoor models. Proair and WILLIS have no QMID on file and are not ranked.

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CompareData as of updated · sources

Against comparable models

Each cell is the share of same-size, same-type models that the manufacturer’s typical model beats (50% is typical); the higher score is in bold. Raw medians are underneath for context: they depend on which sizes each one makes, so they are not compared.
Proair and WILLIS on every ratingPeer scores, 0–100 · grey ticks: every ranked manufacturer · shaded: the middle half of each one’s modelsMeasured against models of the same size and duct type, Proair and WILLIS split the 6 ratings 3–3.
  • Proair
  • WILLIS
  • Other ranked manufacturers
ProairWILLIS

Source: AHRI Directory, NEEP · as of

Average peer percentile, raw median and rank among ranked manufacturers
RatingProairWILLIS
Efficiency index50%median —51%median —
COP at 5°F45% (higher)median 1.9139% (higher)median 1.84
Capacity retention at 5°F65% (higher)median 80%64% (higher)median 76%
HSPF277% (higher)median 9.452% (higher)median 9.0
SEER248%median 15.655%median 21.0
EER226%median 10.046%median 12.0
Heating capacity at 5°F67%median 22,600 Btu/h68%median 13,600 Btu/h
Outdoor models1115
AHRI certifications2029

Share of models meeting each standard

Percent of each manufacturer’s models with a qualifying certification
StandardProairWILLIS
CEE 2025 Tier 1 (Split ASHP)45.5%5 models86.7%13 models
CEE 2026 Tier 1 (Split ASHP)45.5%5 models80%12 models
CEE Advanced Tier (Split ASHP)0%0 models0%0 models
Xcel Energy Colorado cold-climate ASHP (2025)63.6%7 models86.7%13 models
DOE Cold Climate Heat Pump Challenge0%0 models0%0 models
ENERGY STAR Cold Climate0%0 models73.3%11 models

Sizes and duct types offered

Models in each peer group, with the efficiency index of those models against the rest of the group.
Side by side, inside each size and duct typeShape: every model of the group · bars: each manufacturer’s middle half, median dot, 10th–90th line · 3 groups where both have models
  • Proair
  • WILLIS
  • All models of the group
Ducted, up to 1.5 tons2.00884 modelsDucted, 2 tons2.00821 modelsDucted, 2.5–3 tons1.901,614 modelsDucted, 3.5–4.5 tons1.911,492 modelsNon-ducted, up to 1.5 tons1.902,417 modelsNon-ducted, 2 tons1.87611 modelsNon-ducted, 2.5–3 tons1.85975 modelsmedian

Raw ratings are only placed side by side within one size and duct type, where they are comparable.

Source: AHRI Directory · as of

Models per peer group · efficiency index within the group
Size and duct typeProairWILLIS
Ducted, 2 tons3 · index 55%1 · index 46%
Ducted, 2.5–3 tons6 · index 46%4 · index 51%
Ducted, 3.5–4.5 tons2 · index 53%2 · index 55%
Ducted, up to 1.5 tonsNone1 · index 32%
Non-ducted, up to 1.5 tonsNone8 · index 44%
Non-ducted, 2 tonsNone1 · index 72%
Non-ducted, 2.5–3 tonsNone3 · index 68%

Cold-climate and all-around picks, size class by size class

Each manufacturer’s best model on each board in every size and duct type, side by side; the higher score is in bold. Both scores are 0–100 against every model of that size class (the line on each bar is 50, the typical model there), so the two compare fairly even when they make different sizes.

Cold-climate picks

Best cold-climate pick per size and duct type (keeps at least 70% of its heat at 5°F). Qualifies when its capacity retention at 5°F (capacity at 5°F as a share of capacity at 47°F) is at least 70% and Capacity retention at 5°F, COP at 5°F, HSPF2 are all rated. Score = the equal-weight mean of its peer percentiles on Capacity retention at 5°F, COP at 5°F, HSPF2 (share of the other models in its peer group it beats, 0–100), all from one certified pairing: in each duct type a model is sold in, its qualifying pairing of that type with the best score; equal scores (one decimal) go to the higher heating capacity at 5°F.
Size and duct typeProairCold-climate score, best modelWILLISCold-climate score, best model
Ducted, up to 1.5 tonsNo models in this size class36.0(50 is the typical model of its size class)MZUHW18KCH21S2-O1 of 1 models qualify · AHRI 214810334
Ducted, 2 tons67.3(50 is the typical model of its size class) (higher)P15-24REFN1with ducted air handler PAC-24B-HWDN13 of 3 models qualify · AHRI 21544995750.1(50 is the typical model of its size class)MZUHW24KCH21S2-O1 of 1 models qualify · AHRI 214810335
Ducted, 2.5–3 tons78.6(50 is the typical model of its size class) (higher)P30-40HFN1-Dwith ducted air handler PAC-36C-HWND14 of 6 models qualify · AHRI 21544996055.3(50 is the typical model of its size class)FLEX24/36KUHwith ducted air handler FLEXAH24/36K4 of 4 models qualify · AHRI 214137765
Ducted, 3.5–4.5 tons73.8(50 is the typical model of its size class) (higher)P30-48HFN1-Dwith ducted air handler PAH-48HWFN12 of 2 models qualify · AHRI 21544995556.7(50 is the typical model of its size class)FLEX48/60KUHwith ducted air handler FLEXAH48/60K2 of 2 models qualify · AHRI 214797686
Non-ducted, up to 1.5 tonsNo models in this size class73.5(50 is the typical model of its size class)MZUHW18KCH21S2-O7 of 8 models qualify · AHRI 214810331
Non-ducted, 2 tonsNo models in this size class76.1(50 is the typical model of its size class)MZUHW24KCH21S2-O1 of 1 models qualify · AHRI 214810332
Non-ducted, 2.5–3 tonsNo models in this size class73.7(50 is the typical model of its size class)MZUHW42KCH21S2-O3 of 3 models qualify · AHRI 214810330

All-around best

Best all-around model per size and duct type. Score = 50% heating, the mean of its peer percentiles on COP at 5°F, Capacity retention at 5°F, HSPF2, plus 50% cooling, the mean of its peer percentiles on SEER2 and EER2 (share of the other models in its peer group it beats, 0–100). All five ratings are required; there is no minimum heat kept at 5°F. In each duct type a model is sold in, it is scored on its pairing of that type with the best score; equal scores (one decimal) go to the higher cold-climate score, then the higher heating capacity at 5°F.
Size and duct typeProairAll-around score, best modelWILLISAll-around score, best model
Ducted, up to 1.5 tonsNo models in this size class31.5(50 is the typical model of its size class)MZUHW18KCH21S2-O1 of 1 models have all five ratings · AHRI 214810334
Ducted, 2 tons65.9(50 is the typical model of its size class) (higher)P30-24HFN1with ducted air handler PAH-24HWFN13 of 3 models have all five ratings · AHRI 21755038745.9(50 is the typical model of its size class)MZUHW24KCH21S2-O1 of 1 models have all five ratings · AHRI 214810335
Ducted, 2.5–3 tons68.5(50 is the typical model of its size class) (higher)P30-36HFN1-Swith ducted air handler PAH-36HWFN16 of 6 models have all five ratings · AHRI 21544995453.1(50 is the typical model of its size class)MZUHW30KCH21S2-O4 of 4 models have all five ratings · AHRI 214810336
Ducted, 3.5–4.5 tons53.3(50 is the typical model of its size class)P30-60HFN1-Dwith ducted air handler PAH-60HWFN12 of 2 models have all five ratings · AHRI 21544995657.4(50 is the typical model of its size class) (higher)PRT60KUH2 of 2 models have all five ratings · AHRI 214137764
Non-ducted, up to 1.5 tonsNo models in this size class63.8(50 is the typical model of its size class)HW12KUHR410A-Owith ductless indoor unit HW12KUHR410A-I8 of 8 models have all five ratings · AHRI 216772615
Non-ducted, 2 tonsNo models in this size class71.5(50 is the typical model of its size class)MZUHW24KCH21S2-O1 of 1 models have all five ratings · AHRI 214810332
Non-ducted, 2.5–3 tonsNo models in this size class70.2(50 is the typical model of its size class)MZUHW42KCH21S2-O3 of 3 models have all five ratings · AHRI 214810330

All-around board, every manufacturer

Standout model on each rating

Each manufacturer’s model that beats the largest share of comparable models on the rating; the higher share is in bold.
Top model per rating by peer percentile, with its AHRI-certified value and peer group
RatingProairWILLIS
COP at 5°Fbeats 74% · 2.20P15-24REFN1Ducted, 2 tonsbeats 90% · 2.23MZUHW18KCH21S2-ONon-ducted, up to 1.5 tons
Capacity retention at 5°Fbeats 92% · 92%P30-48HFN1-DDucted, 3.5–4.5 tonsbeats 85% · 89%MZUHW30KCH21S2-ODucted, 2.5–3 tons
HSPF2beats 93% · 10.0P30-40HFN1-DDucted, 2.5–3 tonsbeats 82% · 10.0MZUHW36KCH21S2-ONon-ducted, 2.5–3 tons
SEER2beats 69% · 17.3P30-30HFN1Ducted, 2.5–3 tonsbeats 83% · 24.0PUHW12KCH24S2-ONon-ducted, up to 1.5 tons
EER2beats 67% · 11.7P30-36HFN1-SDucted, 2.5–3 tonsbeats 84% · 12.5MZUHW30KCH21S2-ONon-ducted, 2.5–3 tons
Heating capacity at 5°Fbeats 96% · 38,000 Btu/hP30-36HFN1-SDucted, 2.5–3 tonsbeats 84% · 13,800 Btu/hMZUHW18KCH21S2-ONon-ducted, up to 1.5 tons

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