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.

K&A and ZEPHYR 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, ZEPHYR scores higher on 6 of the 6 ratings.

K&A
ZEPHYR
Other ranked manufacturers

Source: AHRI Directory, NEEP · as of Oct 11, 2026

Average peer percentile, raw median and rank among ranked manufacturers
Rating	K&A	ZEPHYR
Efficiency index	30%median —	63%median —
COP at 5°F	31%median 1.80	57%median 2.00
Capacity retention at 5°F	39%median 71%	64%median 80%
HSPF2	33%median 7.6	59%median 10.0
SEER2	27%median 14.6	67%median 22.0
EER2	28%median 9.9	65%median 12.3
Heating capacity at 5°F	44%median 18,800 Btu/h	57%median 13,400 Btu/h
Outdoor models	23	23
AHRI certifications	23	49

Share of models meeting each standard

Percent of each manufacturer’s models with a qualifying certification
Standard	K&A	ZEPHYR
CEE 2025 Tier 1 (Split ASHP)	17.4%4 models	100%23 models
CEE 2026 Tier 1 (Split ASHP)	17.4%4 models	95.7%22 models
CEE Advanced Tier (Split ASHP)	0%0 models	8.7%2 models
Xcel Energy Colorado cold-climate ASHP (2025)	17.4%4 models	82.6%19 models
DOE Cold Climate Heat Pump Challenge	0%0 models	8.7%2 models
ENERGY STAR Cold Climate	0%0 models	73.9%17 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 · 6 groups where both have models

K&A
ZEPHYR
All models of the group

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

Source: AHRI Directory · as of Oct 11, 2026

Models per peer group · efficiency index within the group
Size and duct type	K&A	ZEPHYR
Ducted, up to 1.5 tons	1 · index —	1 · index 65%
Ducted, 2 tons	4 · index 37%	1 · index 80%
Ducted, 2.5–3 tons	5 · index 26%	3 · index 71%
Ducted, 3.5–4.5 tons	9 · index 39%	2 · index 71%
Ducted, 5 tons and up	None	1 · index 81%
Non-ducted, up to 1.5 tons	3 · index 13%	14 · index 62%
Non-ducted, 2 tons	1 · index 13%	2 · index 48%
Non-ducted, 2.5–3 tons	None	2 · index 63%
Non-ducted, 3.5–4.5 tons	None	1 · index 44%

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 type	K&ACold-climate score, best model	ZEPHYRCold-climate score, best model
Ducted, up to 1.5 tons	None on this board (0 of 1 models qualify)	66.2(50 is the typical model of its size class)ZE-518M2251 of 1 models qualify · AHRI 216684162
Ducted, 2 tons	60.4(50 is the typical model of its size class)DIVINE-24K220V-7-Owith ducted air handler DIVINE-24K220V-7-I3 of 4 models qualify · AHRI 217656088	82.1(50 is the typical model of its size class) (higher)ZE-624HPAwith ducted air handler AH-624A1 of 1 models qualify · AHRI 215381145
Ducted, 2.5–3 tons	59.2(50 is the typical model of its size class)DIVINE-36K220V-7-Owith ducted air handler DIVINE-36K220V-7-I1 of 5 models qualify · AHRI 217656089	87.9(50 is the typical model of its size class) (higher)ZE-636HPAwith ducted air handler AH-636A3 of 3 models qualify · AHRI 215381146
Ducted, 3.5–4.5 tons	72.2(50 is the typical model of its size class)DIVINE-48K220V-7-Owith ducted air handler DIVINE-48K220V-7-I4 of 9 models qualify · AHRI 217656090	77.3(50 is the typical model of its size class) (higher)ZE-648HPAwith ducted air handler AH-648A2 of 2 models qualify · AHRI 215381147
Ducted, 5 tons and up	No models in this size class	88.7(50 is the typical model of its size class)ZE-660HPAwith ducted air handler AH-660A1 of 1 models qualify · AHRI 215381148
Non-ducted, up to 1.5 tons	None on this board (0 of 3 models qualify)	89.7(50 is the typical model of its size class)ZE-09UB32Owith ductless indoor unit ZE-09UB32I10 of 14 models qualify · AHRI 217596868
Non-ducted, 2 tons	None on this board (0 of 1 models qualify)	54.1(50 is the typical model of its size class)ZE-24CB25Owith ductless indoor unit ZE-24CB25AI2 of 2 models qualify · AHRI 218046582
Non-ducted, 2.5–3 tons	No models in this size class	53.7(50 is the typical model of its size class)ZE-536M4252 of 2 models qualify · AHRI 216684171
Non-ducted, 3.5–4.5 tons	No models in this size class	16.4(50 is the typical model of its size class)ZE-542M5251 of 1 models qualify · AHRI 216684168

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 type	K&AAll-around score, best model	ZEPHYRAll-around score, best model
Ducted, up to 1.5 tons	None on this board (0 of 1 models have all five ratings)	64.6(50 is the typical model of its size class)ZE-518M2251 of 1 models have all five ratings · AHRI 216684162
Ducted, 2 tons	68.1(50 is the typical model of its size class)DIVINE-24K220V-7-Owith ducted air handler DIVINE-24K220V-7-I3 of 4 models have all five ratings · AHRI 217656088	79.5(50 is the typical model of its size class) (higher)ZE-624HPAwith ducted air handler AH-624A1 of 1 models have all five ratings · AHRI 215381145
Ducted, 2.5–3 tons	57.5(50 is the typical model of its size class)DIVINE-36K220V-7-Owith ducted air handler DIVINE-36K220V-7-I3 of 5 models have all five ratings · AHRI 217656089	82.3(50 is the typical model of its size class) (higher)ZE-636HPAwith ducted air handler AH-636A3 of 3 models have all five ratings · AHRI 215381146
Ducted, 3.5–4.5 tons	72.6(50 is the typical model of its size class)DIVINE-48K220V-7-Owith ducted air handler DIVINE-48K220V-7-I6 of 9 models have all five ratings · AHRI 217656090	82.3(50 is the typical model of its size class) (higher)ZE-648HPAwith ducted air handler AH-648A2 of 2 models have all five ratings · AHRI 215381147
Ducted, 5 tons and up	No models in this size class	81.1(50 is the typical model of its size class)ZE-660HPAwith ducted air handler AH-660A1 of 1 models have all five ratings · AHRI 215381148
Non-ducted, up to 1.5 tons	22.1(50 is the typical model of its size class)MAJESTIC-12K110V-S2with ductless indoor unit MAJESTIC-12K110V-S23 of 3 models have all five ratings · AHRI 216723132	94.5(50 is the typical model of its size class) (higher)ZE-09UB32Owith ductless indoor unit ZE-09UB32I14 of 14 models have all five ratings · AHRI 217596868
Non-ducted, 2 tons	13.4(50 is the typical model of its size class)MAJESTIC-24K220V-S2with ductless indoor unit MAJESTIC-24K220V-S21 of 1 models have all five ratings · AHRI 216723135	61.3(50 is the typical model of its size class) (higher)ZE-24CB25Owith ductless indoor unit ZE-24CB25AI2 of 2 models have all five ratings · AHRI 218046582
Non-ducted, 2.5–3 tons	No models in this size class	64.2(50 is the typical model of its size class)ZE-527M3252 of 2 models have all five ratings · AHRI 216684164
Non-ducted, 3.5–4.5 tons	No models in this size class	43.7(50 is the typical model of its size class)ZE-542M5251 of 1 models have all five ratings · AHRI 216684168

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
Rating	K&A	ZEPHYR
COP at 5°F	beats 86% · 2.30DIVINE-48K220V-7-ODucted, 3.5–4.5 tons	beats 100% · 2.53ZE-18CB22ONon-ducted, up to 1.5 tons
Capacity retention at 5°F	beats 57% · 79%DIVINE-24K220V-7-ODucted, 2 tons	beats 94% · 75%ZE-660HPADucted, 5 tons and up
HSPF2	beats 74% · 9.2DIVINE-48K220V-7-ODucted, 3.5–4.5 tons	beats 96% · 10.5ZE-636HPADucted, 2.5–3 tons
SEER2	beats 81% · 18.5DIVINE-48K220V-7-ODucted, 3.5–4.5 tons	beats 99% · 32.0ZE-09UB32ONon-ducted, up to 1.5 tons
EER2	beats 81% · 12.5DIVINE-24K220V-7-ODucted, 2 tons	beats 100% · 18.4ZE-09UB32ONon-ducted, up to 1.5 tons
Heating capacity at 5°F	beats 68% · 40,000 Btu/hDIVINE-60K220V-7-ODucted, 3.5–4.5 tons	beats 93% · 18,000 Btu/hZE-18CB25ONon-ducted, up to 1.5 tons

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K&A vs ZEPHYR heat pumps