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First Co. vs WILLIS heat pumps

Measured against models of the same size and duct type, WILLIS scores higher on 6 of the 6 ratings. First Co. has 21 outdoor models, WILLIS has 29 outdoor models. First Co. 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.
First Co. 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, WILLIS scores higher on 6 of the 6 ratings.
  • First Co.
  • WILLIS
  • Other ranked manufacturers
First Co.WILLIS

Source: AHRI Directory, NEEP · as of

Average peer percentile, raw median and rank among ranked manufacturers
RatingFirst Co.WILLIS
Efficiency index11%median —63%median —
COP at 5°F34%median 1.9044%median 2.00
Capacity retention at 5°F12%median 49%71%median 90%
HSPF21%median 6.350%median 10.0
SEER20%median 11.969%median 21.0
EER212%median 10.072%median 12.5
Heating capacity at 5°F14%median 8,000 Btu/h65%median 19,000 Btu/h
Outdoor models2129
AHRI certifications6185

Share of models meeting each standard

Percent of each manufacturer’s models with a qualifying certification
StandardFirst Co.WILLIS
CEE 2025 Tier 1 (Split ASHP)0%0 models96.6%28 models
CEE 2026 Tier 1 (Split ASHP)0%0 models96.6%28 models
CEE Advanced Tier (Split ASHP)0%0 models10.3%3 models
Xcel Energy Colorado cold-climate ASHP (2025)0%0 models96.6%28 models
DOE Cold Climate Heat Pump Challenge0%0 models10.3%3 models
ENERGY STAR Cold Climate0%0 models86.2%25 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
  • First Co.
  • WILLIS
  • All models of the group
Ducted, up to 1.5 tons1.901,783 modelsDucted, 2 tons2.001,090 modelsDucted, 2.5–3 tons2.001,909 modelsDucted, 3.5–4.5 tons2.002,224 modelsNon-ducted, up to 1.5 tons1.953,455 modelsNon-ducted, 2 tons2.00863 modelsNon-ducted, 2.5–3 tons2.001,106 modelsNon-ducted, 3.5–4.5 tons2.00564 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 typeFirst Co.WILLIS
Ducted, up to 1.5 tons11 · index 9%7 · index 71%
Ducted, 2 tons7 · index 13%5 · index 67%
Ducted, 2.5–3 tons3 · index 15%3 · index 68%
Ducted, 3.5–4.5 tonsNone3 · index 77%
Non-ducted, up to 1.5 tonsNone13 · index 58%
Non-ducted, 2 tonsNone4 · index 63%
Non-ducted, 2.5–3 tonsNone6 · index 47%
Non-ducted, 3.5–4.5 tonsNone1 · 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 typeFirst Co.Cold-climate score, best modelWILLISCold-climate score, best model
Ducted, up to 1.5 tonsNone on this board (0 of 11 models qualify)69.9(50 is the typical model of its size class)PUHW09KR32-Owith ducted air handler WHEDT09K7 of 7 models qualify · AHRI 217560051
Ducted, 2 tonsNone on this board (0 of 7 models qualify)76.2(50 is the typical model of its size class)FLEX24KUHR32with ducted air handler FLEXAH24KR324 of 4 models qualify · AHRI 216720953
Ducted, 2.5–3 tonsNone on this board (0 of 3 models qualify)87.9(50 is the typical model of its size class)HW-COND36Kwith ducted air handler HW-AHU36K4 of 4 models qualify · AHRI 216772612
Ducted, 3.5–4.5 tonsNo models in this size class85.1(50 is the typical model of its size class)FLEX60KUHR32with ducted air handler FLEXAH60KR323 of 3 models qualify · AHRI 216720958
Non-ducted, up to 1.5 tonsNo models in this size class87.2(50 is the typical model of its size class)AUHW09KR32-Owith ductless indoor unit AUHW09KR32-I13 of 13 models qualify · AHRI 217007963
Non-ducted, 2 tonsNo models in this size class70.3(50 is the typical model of its size class)PUHW24KR32-Owith ductless indoor unit PUHW24KR32-I3 of 4 models qualify · AHRI 217007962
Non-ducted, 2.5–3 tonsNo models in this size class77.2(50 is the typical model of its size class)MZUHW36KR32-O6 of 6 models qualify · AHRI 216772311
Non-ducted, 3.5–4.5 tonsNo models in this size class66.5(50 is the typical model of its size class)MZUHW42KR32-O1 of 1 models qualify · AHRI 216772312

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 typeFirst Co.All-around score, best modelWILLISAll-around score, best model
Ducted, up to 1.5 tons25.1(50 is the typical model of its size class)18WHHPBAwith ducted air handler 37CLX(*,Q,W)11 of 11 models have all five ratings · AHRI 21683193183.6(50 is the typical model of its size class) (higher)PUHW09KR32-Owith ducted air handler WHEDT09K7 of 7 models have all five ratings · AHRI 217560051
Ducted, 2 tons30.4(50 is the typical model of its size class)24WHHPBAwith ducted air handler 37CLX(*,Q,W)7 of 7 models have all five ratings · AHRI 21683193273.1(50 is the typical model of its size class) (higher)FLEX24KUHR32with ducted air handler FLEXAH24KR325 of 5 models have all five ratings · AHRI 216720953
Ducted, 2.5–3 tons20.0(50 is the typical model of its size class)30WHHPBAwith ducted air handler 37CLX(*,Q,W)3 of 3 models have all five ratings · AHRI 21683193382.3(50 is the typical model of its size class) (higher)HW-COND36Kwith ducted air handler HW-AHU36K3 of 3 models have all five ratings · AHRI 216772612
Ducted, 3.5–4.5 tonsNo models in this size class83.1(50 is the typical model of its size class)FLEX48KUHR32with ducted air handler FLEXAH48KR32Also listed as FLEX60KUHR323 of 3 models have all five ratings · AHRI 216720956
Non-ducted, up to 1.5 tonsNo models in this size class92.6(50 is the typical model of its size class)AUHW09KR32-Owith ductless indoor unit AUHW09KR32-I13 of 13 models have all five ratings · AHRI 217007963
Non-ducted, 2 tonsNo models in this size class82.1(50 is the typical model of its size class)PUHW24KR32-Owith ductless indoor unit PUHW24KR32-I4 of 4 models have all five ratings · AHRI 217007962
Non-ducted, 2.5–3 tonsNo models in this size class70.5(50 is the typical model of its size class)MZUHW30KR32-O6 of 6 models have all five ratings · AHRI 216772310
Non-ducted, 3.5–4.5 tonsNo models in this size class67.7(50 is the typical model of its size class)MZUHW42KR32-O1 of 1 models have all five ratings · AHRI 216772312

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
RatingFirst Co.WILLIS
COP at 5°Fbeats 63% · 2.00EHE12***D***AAlso listed as EHE12***E***ADucted, up to 1.5 tonsbeats 88% · 2.10MZUHW36KR32-ONon-ducted, 2.5–3 tons
Capacity retention at 5°Fbeats 24% · 54%EPE30***DAlso listed as EPE30***EDucted, 2.5–3 tonsbeats 94% · 100%AUHW24KR32-ONon-ducted, 2 tons
HSPF2beats 16% · 6.830WHHPBADucted, 2.5–3 tonsbeats 96% · 10.5HW-COND36KDucted, 2.5–3 tons
SEER2beats 20% · 14.218WHHPBADucted, up to 1.5 tonsbeats 100% · 24.5AUHW18KR32-ODucted, up to 1.5 tons
EER2beats 76% · 12.518WHHPBADucted, up to 1.5 tonsbeats 98% · 16.8AUHW09KR32-ONon-ducted, up to 1.5 tons
Heating capacity at 5°Fbeats 38% · 8,000 Btu/hEHE18***D***AAlso listed as EHE18***E***ADucted, up to 1.5 tonsbeats 98% · 54,000 Btu/hFLEX60KUHR32Ducted, 3.5–4.5 tons

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