Acekool vs ATK heat pumps

Measured against models of the same size and duct type, ATK scores higher on 4 of the 6 ratings. Acekool has 13 outdoor models, ATK has 13 outdoor models. Acekool and ATK have no QMID on file and are not ranked.

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CompareData as of Oct 11, 2026updated Oct 11, 2026 · 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.

Acekool and ATK 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, ATK scores higher on 4 of the 6 ratings.

Acekool
ATK
Other ranked manufacturers

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

Average peer percentile, raw median and rank among ranked manufacturers
Rating	Acekool	ATK
Efficiency index	36%median —	47%median —
COP at 5°F	21%median 1.80	51%median 1.91
Capacity retention at 5°F	39%median 70%	57%median 79%
HSPF2	32%median 8.5	75%median 9.4
SEER2	46% (higher)median 19.0	44% (higher)median 15.5
EER2	38% (higher)median 10.0	20% (higher)median 10.0
Heating capacity at 5°F	35%median 8,700 Btu/h	64%median 27,000 Btu/h
Outdoor models	13	13
AHRI certifications	13	24

Share of models meeting each standard

Percent of each manufacturer’s models with a qualifying certification
Standard	Acekool	ATK
CEE 2025 Tier 1 (Split ASHP)	84.6%11 models	53.8%7 models
CEE 2026 Tier 1 (Split ASHP)	76.9%10 models	38.5%5 models
CEE Advanced Tier (Split ASHP)	0%0 models	0%0 models
Xcel Energy Colorado cold-climate ASHP (2025)	61.5%8 models	46.2%6 models
DOE Cold Climate Heat Pump Challenge	0%0 models	0%0 models
ENERGY STAR Cold Climate	30.8%4 models	0%0 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 · 0 groups where both have models

Acekool
ATK
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	Acekool	ATK
Ducted, up to 1.5 tons	None	2 · index 43%
Ducted, 2 tons	None	2 · index 49%
Ducted, 2.5–3 tons	None	5 · index 45%
Ducted, 3.5–4.5 tons	None	4 · index 50%
Non-ducted, up to 1.5 tons	10 · index 37%	None
Non-ducted, 2 tons	2 · index 35%	None
Non-ducted, 2.5–3 tons	1 · index 23%	None

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	AcekoolCold-climate score, best model	ATKCold-climate score, best model
Ducted, up to 1.5 tons	No models in this size class	64.3(50 is the typical model of its size class)ACI-AUO18SHP-Mwith ducted air handler ACI-BCO24CP171 of 2 models qualify · AHRI 212386850
Ducted, 2 tons	No models in this size class	69.5(50 is the typical model of its size class)ACI-AUO24SHP-Mwith ducted air handler ACI-AUI24VHE2 of 2 models qualify · AHRI 212386849
Ducted, 2.5–3 tons	No models in this size class	78.6(50 is the typical model of its size class)ACI-AUO36SHP-Mwith ducted air handler ACI-CCO36CP213 of 5 models qualify · AHRI 212386847
Ducted, 3.5–4.5 tons	No models in this size class	73.8(50 is the typical model of its size class)ACI-AUO48SHP-Mwith ducted air handler ACI-AUI48VHE2 of 4 models qualify · AHRI 212386843
Non-ducted, up to 1.5 tons	47.5(50 is the typical model of its size class)CMS12-2 PROwith ductless indoor unit CMS12-2 PRO8 of 10 models qualify · AHRI 216980963	No models in this size class
Non-ducted, 2 tons	None on this board (0 of 2 models qualify)	No models in this size class
Non-ducted, 2.5–3 tons	None on this board (0 of 1 models qualify)	No models in this size class

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	AcekoolAll-around score, best model	ATKAll-around score, best model
Ducted, up to 1.5 tons	No models in this size class	51.9(50 is the typical model of its size class)ACI-AUO18SHP-Mwith ducted air handler ACI-BCO24CP172 of 2 models have all five ratings · AHRI 212386850
Ducted, 2 tons	No models in this size class	67.3(50 is the typical model of its size class)ACI-AUO24SHP-Mwith ducted air handler ACI-AUI24VHE2 of 2 models have all five ratings · AHRI 212386849
Ducted, 2.5–3 tons	No models in this size class	57.8(50 is the typical model of its size class)ACI-AUO36SHP-Mwith ducted air handler ACI-AUI36VHE5 of 5 models have all five ratings · AHRI 212386845
Ducted, 3.5–4.5 tons	No models in this size class	53.3(50 is the typical model of its size class)ACI-AUO60SHP-Mwith ducted air handler ACI-AUI60VHE3 of 3 models have all five ratings · AHRI 212386842
Ducted, 5 tons and up	No models in this size class	45.6(50 is the typical model of its size class)ACI-SDAUO60SHPwith ducted air handler ACI-AUI60VHE1 of 1 models have all five ratings · AHRI 213430648
Non-ducted, up to 1.5 tons	60.6(50 is the typical model of its size class)CMS9-2 PROwith ductless indoor unit CMS9-2 PRO10 of 10 models have all five ratings · AHRI 216980962	No models in this size class
Non-ducted, 2 tons	46.0(50 is the typical model of its size class)CMS24 PROwith ductless indoor unit CMS24 PRO2 of 2 models have all five ratings · AHRI 213857786	No models in this size class
Non-ducted, 2.5–3 tons	23.4(50 is the typical model of its size class)CMS36with ductless indoor unit CMS361 of 1 models have all five ratings · AHRI 213804783	No models in this size class

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	Acekool	ATK
COP at 5°F	beats 26% · 1.80CMS24Non-ducted, 2 tons	beats 76% · 2.20ACI-AUO18SHP-MDucted, up to 1.5 tons
Capacity retention at 5°F	beats 64% · 77%CMS9-2 PRONon-ducted, up to 1.5 tons	beats 92% · 92%ACI-AUO48SHP-MDucted, 3.5–4.5 tons
HSPF2	beats 57% · 9.5CMS12-2 PRONon-ducted, up to 1.5 tons	beats 93% · 10.0ACI-AUO36SHP-MDucted, 2.5–3 tons
SEER2	beats 79% · 23.5CMS9-2 PRONon-ducted, up to 1.5 tons	beats 69% · 17.3ACI-SDAUO30SHPDucted, 2.5–3 tons
EER2	beats 68% · 13.0CMS12 PRONon-ducted, up to 1.5 tons	beats 50% · 11.7ACI-AUO24SHP-MDucted, 2 tons
Heating capacity at 5°F	beats 66% · 11,900 Btu/hCMS12 PRONon-ducted, up to 1.5 tons	beats 95% · 48,500 Btu/hACI-AUO60SHP-MDucted, 3.5–4.5 tons

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