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.

Innovair and ZERO 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, Innovair scores higher on 4 of the 6 ratings.

Innovair
ZERO
Other ranked manufacturers

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

Average peer percentile, raw median and rank among ranked manufacturers
Rating	Innovair	ZERO
Efficiency index	56% (higher)median — · 12th ranked	49% (higher)median —
COP at 5°F	51% (higher)median 1.91 · 17th ranked	48% (higher)median 1.89
Capacity retention at 5°F	64% (higher)median 82% · 6th ranked	43% (higher)median 70%
HSPF2	53% (higher)median 8.8 · 13th ranked	46% (higher)median 8.6
SEER2	50%median 17.0 · 12th ranked	53%median 19.0
EER2	42%median 10.6 · 25th ranked	46%median 11.0
Heating capacity at 5°F	64% (higher)median 21,555 Btu/h · 4th ranked	44% (higher)median 11,700 Btu/h
Outdoor models	44	69
AHRI certifications	91	89

Share of models meeting each standard

Percent of each manufacturer’s models with a qualifying certification
Standard	Innovair	ZERO
CEE 2025 Tier 1 (Split ASHP)	52.3%23 models	59.4%41 models
CEE 2026 Tier 1 (Split ASHP)	47.7%21 models	55.1%38 models
CEE Advanced Tier (Split ASHP)	0%0 models	0%0 models
Xcel Energy Colorado cold-climate ASHP (2025)	47.7%21 models	47.8%33 models
DOE Cold Climate Heat Pump Challenge	0%0 models	0%0 models
ENERGY STAR Cold Climate	52.3%23 models	24.6%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 · 9 groups where both have models

Innovair
ZERO
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	Innovair	ZERO
Ducted, up to 1.5 tons	5 · index 53%	2 · index 59%
Ducted, 2 tons	5 · index 63%	5 · index 69%
Ducted, 2.5–3 tons	7 · index 51%	7 · index 57%
Ducted, 3.5–4.5 tons	6 · index 53%	9 · index 63%
Ducted, 5 tons and up	1 · index 42%	1 · index 57%
Non-ducted, up to 1.5 tons	11 · index 68%	33 · index 48%
Non-ducted, 2 tons	5 · index 68%	9 · index 49%
Non-ducted, 2.5–3 tons	7 · index 44%	8 · index 39%
Non-ducted, 3.5–4.5 tons	1 · index 45%	3 · index 50%

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	InnovairCold-climate score, best model	ZEROCold-climate score, best model
Ducted, up to 1.5 tons	86.9(50 is the typical model of its size class) (higher)SHV18H2R20with ducted air handler WEV18H2R194 of 5 models qualify · AHRI 213255597	52.0(50 is the typical model of its size class)Z3SOV-18HDM-US1 of 2 models qualify · AHRI 214723150
Ducted, 2 tons	75.6(50 is the typical model of its size class)MHD-24with ducted air handler MHD-CC2.0-17.5-M4 of 5 models qualify · AHRI 210365430	80.3(50 is the typical model of its size class) (higher)ZSOV-24HDM-USwith ducted air handler ZDV-24HDM-US2 of 5 models qualify · AHRI 212928560
Ducted, 2.5–3 tons	78.6(50 is the typical model of its size class) (higher)SHV36H2R20with ducted air handler MAC36H2124E4 of 7 models qualify · AHRI 213160476	57.4(50 is the typical model of its size class)Z3SOV-27HDM-US1 of 7 models qualify · AHRI 213732663
Ducted, 3.5–4.5 tons	73.8(50 is the typical model of its size class)SHV48H2R20with ducted air handler DEV48H2R193 of 6 models qualify · AHRI 210343157	74.9(50 is the typical model of its size class) (higher)Z5SOV-48HDM-US1 of 9 models qualify · AHRI 213732669
Ducted, 5 tons and up	None on this board (0 of 1 models qualify)	None on this board (0 of 1 models qualify)
Non-ducted, up to 1.5 tons	80.1(50 is the typical model of its size class)EIN10H2V32(O)with ductless indoor unit EIN10H2V32(I)7 of 11 models qualify · AHRI 206330207	86.0(50 is the typical model of its size class) (higher)ZMSB-09HV-USHHwith ductless indoor unit ZMSB-09HV-USHH24 of 33 models qualify · AHRI 213917748
Non-ducted, 2 tons	68.5(50 is the typical model of its size class)EIN24H2V32(O)with ductless indoor unit EIN24H2V32(I)3 of 5 models qualify · AHRI 206330210	74.2(50 is the typical model of its size class) (higher)ZSOV-24HDM-USwith ductless indoor unit ZEV-24HDM-US4 of 9 models qualify · AHRI 212928564
Non-ducted, 2.5–3 tons	64.0(50 is the typical model of its size class) (higher)VOM36H7R4P71 of 7 models qualify · AHRI 207821954	49.3(50 is the typical model of its size class)Z3SOV-27HDM-US1 of 8 models qualify · AHRI 213732662
Non-ducted, 3.5–4.5 tons	41.9(50 is the typical model of its size class)VOM42H7R5P71 of 1 models qualify · AHRI 207821958	80.5(50 is the typical model of its size class) (higher)Z5SOV-48HDM-US2 of 3 models qualify · AHRI 213732668

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	InnovairAll-around score, best model	ZEROAll-around score, best model
Ducted, up to 1.5 tons	82.8(50 is the typical model of its size class) (higher)SHV18H2R20with ducted air handler WEV18H2R195 of 5 models have all five ratings · AHRI 213255597	59.4(50 is the typical model of its size class)Z3SOV-18HDM-US1 of 2 models have all five ratings · AHRI 214723150
Ducted, 2 tons	71.6(50 is the typical model of its size class)VOM24H7R3P75 of 5 models have all five ratings · AHRI 207821950	83.8(50 is the typical model of its size class) (higher)ZSOV-24HDM-USwith ducted air handler ZDV-24HDM-US2 of 5 models have all five ratings · AHRI 212928560
Ducted, 2.5–3 tons	78.6(50 is the typical model of its size class) (higher)VOM36H7R4P77 of 7 models have all five ratings · AHRI 207821953	71.5(50 is the typical model of its size class)Z3SOV-27HDM-US3 of 7 models have all five ratings · AHRI 213732663
Ducted, 3.5–4.5 tons	60.7(50 is the typical model of its size class)VOM42H7R5P76 of 6 models have all five ratings · AHRI 207821956	82.0(50 is the typical model of its size class) (higher)Z5SOV-48HDM-US2 of 9 models have all five ratings · AHRI 213732669
Ducted, 5 tons and up	41.7(50 is the typical model of its size class)SEV60H2R19with ducted air handler DEV60H2R191 of 1 models have all five ratings · AHRI 208106863	57.1(50 is the typical model of its size class) (higher)ZSOV-60HDM-USwith ducted air handler ZDV-60HDM-US1 of 1 models have all five ratings · AHRI 212928563
Non-ducted, up to 1.5 tons	88.7(50 is the typical model of its size class) (higher)EIN10H2V32(O)with ductless indoor unit EIN10H2V32(I)7 of 11 models have all five ratings · AHRI 206330207	86.7(50 is the typical model of its size class)ZMSB-09HV-USHHwith ductless indoor unit ZMSB-09HV-USHH33 of 33 models have all five ratings · AHRI 213917748
Non-ducted, 2 tons	76.3(50 is the typical model of its size class) (higher)EIN24H2V32(O)with ductless indoor unit EIN24H2V32(I)3 of 5 models have all five ratings · AHRI 206330210	72.0(50 is the typical model of its size class)ZSOV-24HDM-USwith ductless indoor unit ZEV-24HDM-US9 of 9 models have all five ratings · AHRI 212928564
Non-ducted, 2.5–3 tons	69.5(50 is the typical model of its size class) (higher)VOM36H7R4P75 of 7 models have all five ratings · AHRI 207821954	66.7(50 is the typical model of its size class)Z3SOV-27HDM-US8 of 8 models have all five ratings · AHRI 213732662
Non-ducted, 3.5–4.5 tons	44.5(50 is the typical model of its size class)VOM42H7R5P71 of 1 models have all five ratings · AHRI 207821957	73.8(50 is the typical model of its size class) (higher)Z5SOV-48HDM-US3 of 3 models have all five ratings · AHRI 213732668

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	Innovair	ZERO
COP at 5°F	beats 91% · 2.37VEA36H2V18Ducted, 2.5–3 tons	beats 96% · 2.22ZMSB-24HV-USHHNon-ducted, 2 tons
Capacity retention at 5°F	beats 99% · 144%EIN10H2V32(O)Non-ducted, up to 1.5 tons	beats 84% · 87%Z5SOV-48HDM-USDucted, 3.5–4.5 tons
HSPF2	beats 93% · 10.8SHV18H2R20Ducted, up to 1.5 tons	beats 98% · 11.2ZSOV-24HDM-USDucted, 2 tons
SEER2	beats 96% · 21.0VOM24H7R3P7Ducted, 2 tons	beats 99% · 20.9Z5SOV-48HDM-USDucted, 3.5–4.5 tons
EER2	beats 99% · 16.6EIN10H2V32(O)Non-ducted, up to 1.5 tons	beats 95% · 15.8ZMSB-09HV-USHHCAlso listed as ZMSB-09HV-USHHC-ONon-ducted, up to 1.5 tons
Heating capacity at 5°F	beats 96% · 20,000 Btu/hEIN18H2V32(O)Non-ducted, up to 1.5 tons	beats 90% · 17,200 Btu/hZMSB-18HV-USHHCAlso listed as ZMSB-18HV-USHHC-ONon-ducted, up to 1.5 tons

More comparisons

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Innovair vs ZERO heat pumps