ATK heat pump efficiency: 13 outdoor models compared

ATK has 13 heat pump outdoor models certified with this refrigerant group, in 24 AHRI-certified combinations. Each model is compared with models of the same size and duct type, so the scores below do not depend on which sizes ATK makes. ATK has no QMID (IRS Qualified Manufacturer ID) on file, so it is not ranked against other manufacturers.

New to heat pump ratings? The Simple view explains them in plain words →

ManufacturerData as of Oct 9, 2026updated Oct 10, 2026 · sources

Outdoor models: 13
AHRI certifications: 24
Efficiency index: 47%; Typical model vs same-size, same-type peers (13 models)
Meet CEE 2025: 53.8%; 7 models

How ATK compares with comparable models

For each rating: the share of same-size, same-type models that a typical model of this manufacturer beats (50% is typical), its rank, and the raw median for context. Raw medians are not comparable across manufacturers that make different sizes.

ATK against every ranked manufacturerPeer scores, 0–100 · grey ticks: each ranked manufacturer · shaded: the middle half of ATK’s own modelsATK is strongest on HSPF2 (its typical model beats 75% of comparable models) and weakest on EER2 (20%).

ATK
Middle half of its models
Other ranked manufacturers

Source: AHRI Directory, NEEP · as of Oct 9, 2026

Average peer percentile of ATK’s models
Rating	Beats comparable models	Rank	Raw median
Efficiency index13 models scored	47%	Not ranked	—
COP at 5°F13 models scored	51%	Not ranked	1.91
Capacity retention at 5°F13 models scored	57%	Not ranked	79%
HSPF213 models scored	75%	Not ranked	9.4
SEER213 models scored	44%	Not ranked	15.5
EER213 models scored	20%	Not ranked	10.0
Heating capacity at 5°F13 models scored	64%	Not ranked	27,000 Btu/h

Standards met

Share of ATK’s models with at least one qualifying certification
Standard	Share	Models
CEE 2025 Tier 1 (Split ASHP)	53.8%	7
CEE 2026 Tier 1 (Split ASHP)	38.5%	5
CEE Advanced Tier (Split ASHP)	0%	0
Xcel Energy Colorado cold-climate ASHP (2025)	46.2%	6
DOE Cold Climate Heat Pump Challenge	0%	0
ENERGY STAR Cold Climate	0%	0

Sizes and duct types offered

Models per peer group, and how they score against the other models of that group.

ATK’s models inside each size and duct typeShape: every model of the group · blue: the middle half of this manufacturer’s models there, median dot, 10th–90th percentile line

ATK (median, middle 50%, 10th–90th)
All models of the group

Source: AHRI Directory · as of Oct 9, 2026

Share of comparable models beaten, per peer group
Size and duct type	Models	Index	COP@5°F	HSPF2	SEER2
Ducted, up to 1.5 tons	2	43%	64%	48%	40%
Ducted, 2 tons	2	49%	56%	81%	49%
Ducted, 2.5–3 tons	5	45%	48%	78%	34%
Ducted, 3.5–4.5 tons	4	50%	46%	82%	57%

Every ATK model in the market

ATK’s 13 models with a known size and duct type, over the shape of the whole catalog.

ATK models by size and ratingColoured: ATK · grey shapes: all 11,475 models · lines: catalog medians by size

ATK models
Ducted median by size
Non-ducted median by size
Every model at each size (width = count)
Standard threshold

Dots: 13 atk models, each through its representative certification, in the colour of the rating shown. The grey shapes count all 11,475 models, half a ton at a time.

Show the data as a table

COP at 5°F by size and duct type (every model, by rated cooling capacity)
Duct type, size	Models	10th pct.	25th	Median	75th	90th
Ducted, 0.5 tons	175	1.70	1.85	1.90	2.10	2.26
Ducted, 1 ton	340	1.85	1.90	2.00	2.40	2.65
Ducted, 1.5 tons	789	1.75	1.85	2.00	2.20	2.55
Ducted, 2 tons	782	1.73	1.80	2.00	2.10	2.33
Ducted, 2.5 tons	735	1.71	1.80	1.90	2.09	2.48
Ducted, 3 tons	652	1.68	1.70	1.90	2.06	2.36
Ducted, 3.5 tons	641	1.61	1.80	1.95	2.20	2.50
Ducted, 4 tons	367	1.70	1.80	1.91	2.02	2.52
Ducted, 4.5 tons	544	1.70	1.80	1.91	2.08	2.34
Ducted, 5 tons	25	1.80	1.80	1.90	1.90	2.15
Non-ducted, 0.5 tons	717	1.75	1.81	1.97	2.10	2.19
Non-ducted, 1 ton	1,064	1.75	1.80	1.90	2.07	2.25
Non-ducted, 1.5 tons	886	1.80	1.80	1.87	2.07	2.21
Non-ducted, 2 tons	564	1.80	1.80	1.83	2.04	2.21
Non-ducted, 2.5 tons	275	1.80	1.81	1.84	1.86	2.03
Non-ducted, 3 tons	502	1.80	1.80	1.90	2.00	2.09
Non-ducted, 3.5 tons	70	1.82	1.83	1.90	2.00	2.28
Non-ducted, 4 tons	263	1.80	1.80	1.98	2.00	2.10
Non-ducted, 4.5 tons	103	1.77	1.77	1.80	1.97	2.02
Non-ducted, 5 tons	29	1.98	2.00	2.10	2.30	2.47

Source: AHRI Directory · as of Oct 9, 2026

Top ATK models

Its top five cold-climate picks and its top five all-around models across sizes (both scores compare each model with models of its own size and duct type, so sizes compare), then, on each single rating, the model that beats the largest share of comparable models.

Cold-climate picks

Top 5 ATK cold-climate picks across sizes. 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.
# · Outdoor model	Size · type	Cap. 5/47	COP@5°F	HSPF2	Btu/h @5°F	SEER2	Meets	Combos	AHRI ref.	Compared with	Score
1ACI-AUO36SHP-MATKwith ducted air handler ACI-CCO36CP21	3 tons35,000 Btu/h · Ducted	82%	2.00	10.0	32,000	15.2	CEE 25CEE 26Xcel	2	212386847	Ducted, 2.5–3 tons	78.6
2ACI-AUO48SHP-MATKwith ducted air handler ACI-AUI48VHE	4 tons47,000 Btu/h · Ducted	92%	1.90	9.4	46,000	15.6	None	2	212386843	Ducted, 3.5–4.5 tons	73.8
3ACI-AUO60SHP-MATKwith ducted air handler ACI-AUI60VHE	4.5 tons55,000 Btu/h · Ducted	82%	1.91	9.4	48,500	15.3	None	2	212386842	Ducted, 3.5–4.5 tons	71.3
4ACI-AUO24SHP-MATKwith ducted air handler ACI-AUI24VHE	2 tons24,000 Btu/h · Ducted	100%	1.91	10.0	24,071	17.4	CEE 25CEE 26Xcel	2	212386849	Ducted, 2 tons	69.5
5ACI-CCO36CP21ATKwith ducted air handler ACI-CCO36CP21	2.5 tons30,000 Btu/h · Ducted	82%	1.85	9.7	27,000	15.5	Xcel	1	213216270	Ducted, 2.5–3 tons	68.3

All-around best

Top 5 ATK models on the all-around score across sizes. 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.
# · Outdoor model	Size · type	Cap. 5/47	COP@5°F	HSPF2	SEER2	EER2	Meets	Combos	AHRI ref.	Compared with	Score	Heating half	Cooling half	Cold-climate score
1ACI-AUO24SHP-MATKwith ducted air handler ACI-AUI24VHE	2 tons24,000 Btu/h · Ducted	100%	1.91	10.0	17.4	11.7	CEE 25CEE 26Xcel	2	212386849	Ducted, 2 tons	67.3	69.5	65.1	69.5
2ACI-AUO36SHP-MATKwith ducted air handler ACI-AUI36VHE	3 tons36,000 Btu/h · Ducted	92%	1.96	9.5	16.0	10.0	CEE 25CEE 26Xcel	2	212386845	Ducted, 2.5–3 tons	57.8	77.9	37.6	78.6
3ACI-AUO60SHP-MATKwith ducted air handler ACI-AUI60VHE	4.5 tons55,000 Btu/h · Ducted	82%	1.91	9.4	15.3	8.8	None	2	212386842	Ducted, 3.5–4.5 tons	53.3	71.3	35.3	71.3
4ACI-AUO48SHP-MATKwith ducted air handler ACI-AUI48VHE	4 tons47,000 Btu/h · Ducted	92%	1.90	9.4	15.6	8.2	None	2	212386843	Ducted, 3.5–4.5 tons	53.2	73.8	32.6	73.8
5ACI-CCO36CP21ATKwith ducted air handler ACI-CCO36CP21	2.5 tons30,000 Btu/h · Ducted	82%	1.85	9.7	15.5	10.5	Xcel	1	213216270	Ducted, 2.5–3 tons	52.8	68.3	37.4	68.3

Best model on each rating

ATK’s model with the highest peer percentile on each rating, ranked by that one rating only
Rating	Model	Value	Compared with	Beats	AHRI ref.
COP at 5°F	ACI-AUO18SHP-M	2.20	Ducted, up to 1.5 tons	76%	212386850
Capacity retention at 5°F	ACI-AUO48SHP-M	92%	Ducted, 3.5–4.5 tons	92%	212386843
HSPF2	ACI-AUO36SHP-M	10.0	Ducted, 2.5–3 tons	93%	212386847
SEER2	ACI-SDAUO30SHP	17.3	Ducted, 2.5–3 tons	69%	213430650
EER2	ACI-AUO24SHP-M	11.7	Ducted, 2 tons	50%	212386849
Heating capacity at 5°F	ACI-AUO60SHP-M	48,500 Btu/h	Ducted, 3.5–4.5 tons	95%	212386842

All 13 ATK models in Explore

ATK size class by size class: cold-climate and all-around

Its best model on each board in every size and duct type it makes. Both scores are 0–100 against every model of that size class (the line on each bar is 50, the typical model there). Cold-climate picks must keep at least 70% of their heat at 5°F; the all-around score needs all five ratings and has no such bar.

ATK: best cold-climate pick and best all-around model per size and duct type, with how many of its models are on each board (top 5 and 5 per class are in the snapshot)
Size and duct type	Cold-climate pickCold-climate score, best model	All-around bestAll-around score, best model
Ducted, up to 1.5 tons	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	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	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	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	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	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	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	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

All-around board, every manufacturer

Newest ATK certifications

By AHRI reference number; AHRI issues references in increasing order.

The 5 most recently certified ATK outdoor models
Outdoor model	Size · type	COP@5°F	Cap. 5/47	HSPF2	SEER2	Meets	Combos	AHRI ref.
ACI-SDAUO36SHPATKwith ducted air handler ACI-AUI36VHE	3 tons36,000 Btu/h · Ducted	1.90	60%	8.5	16.9	CEE 25	2	213430656
ACI-SDAUO24SHPATKwith ducted air handler ACI-AUI24VHE	2 tons24,000 Btu/h · Ducted	2.10	75%	9.2	17.0	CEE 25CEE 26Xcel	2	213430655
ACI-SDAUO18SHPATKwith ducted air handler ACI-AUI18VHE	1.5 tons18,000 Btu/h · Ducted	2.00	61%	8.8	17.0	CEE 25	2	213430653
ACI-SDAUO48SHPATKwith ducted air handler ACI-AUI48VHE	4 tons47,000 Btu/h · Ducted	1.95	65%	9.4	15.8	None	2	213430651
ACI-SDAUO30SHPATKwith ducted air handler ACI-AUI30VHE	2.5 tons30,000 Btu/h · Ducted	1.70	56%	8.5	17.3	None	2	213430650

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Manufacturers of a similar size, side by side.

Compare with any manufacturer

ATK includes these brand names as listed in AHRI: ATK. Standards are checked against published thresholds; program rules beyond ratings are not checked.