ACC vs YISO heat pumps

Measured against models of the same size and duct type, ACC and YISO split the 6 ratings 3–3. ACC has 4 outdoor models, YISO has 4 outdoor models. ACC and YISO 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.

ACC and YISO 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, ACC and YISO split the 6 ratings 3–3.

ACC
YISO
Other ranked manufacturers

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

Average peer percentile, raw median and rank among ranked manufacturers
Rating	ACC	YISO
Efficiency index	55%median —	75%median —
COP at 5°F	67% (higher)median 2.08	60% (higher)median 2.03
Capacity retention at 5°F	77% (higher)median 59%	65% (higher)median 71%
HSPF2	55%median 8.6	79%median 9.4
SEER2	32%median 15.3	90%median 19.0
EER2	12%median 8.6	75%median 11.9
Heating capacity at 5°F	79% (higher)median 35,600 Btu/h	64% (higher)median 29,800 Btu/h
Outdoor models	4	4
AHRI certifications	5	74

Share of models meeting each standard

Percent of each manufacturer’s models with a qualifying certification
Standard	ACC	YISO
CEE 2025 Tier 1 (Split ASHP)	0%0 models	100%4 models
CEE 2026 Tier 1 (Split ASHP)	0%0 models	100%4 models
CEE Advanced Tier (Split ASHP)	0%0 models	0%0 models
Xcel Energy Colorado cold-climate ASHP (2025)	0%0 models	100%4 models
DOE Cold Climate Heat Pump Challenge	0%0 models	0%0 models
ENERGY STAR Cold Climate	0%0 models	100%4 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 · 2 groups where both have models

ACC
YISO
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	ACC	YISO
Ducted, 2.5–3 tons	1 · index —	1 · index 61%
Ducted, 3.5–4.5 tons	1 · index —	2 · index 78%
Ducted, 5 tons and up	1 · index 55%	None
Ducted, 2 tons	None	1 · index 84%
Non-ducted, 2.5–3 tons	1 · index —	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	ACCCold-climate score, best model	YISOCold-climate score, best model
Ducted, 2 tons	No models in this size class	71.4(50 is the typical model of its size class)YOHA2-36AAwith ducted air handler YAHA1-24BA1 of 1 models qualify · AHRI 214290126
Ducted, 2.5–3 tons	None on this board (0 of 1 models qualify)	61.1(50 is the typical model of its size class)YOHA8-36Awith ducted air handler YAHA2-36AA1 of 1 models qualify · AHRI 215722678
Ducted, 3.5–4.5 tons	None on this board (0 of 1 models qualify)	78.6(50 is the typical model of its size class)YOHA2-60AAwith ducted air handler YAHA1-48BA2 of 2 models qualify · AHRI 214290128
Ducted, 5 tons and up	None on this board (0 of 1 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	ACCAll-around score, best model	YISOAll-around score, best model
Ducted, 2 tons	No models in this size class	84.1(50 is the typical model of its size class)YOHA2-36AAwith ducted air handler YAHA1-24BA2 of 2 models have all five ratings · AHRI 214290126
Ducted, 2.5–3 tons	None on this board (0 of 1 models have all five ratings)	No models in this size class
Ducted, 3.5–4.5 tons	None on this board (0 of 1 models have all five ratings)	86.4(50 is the typical model of its size class)YOHA2-60AAwith ducted air handler YAHA1-48BA2 of 2 models have all five ratings · AHRI 214290128
Ducted, 5 tons and up	54.5(50 is the typical model of its size class)MSH603E18MCAAwith ducted air handler MST363E18ADAA1 of 1 models have all five ratings · AHRI 203991110	No models in this size class
Non-ducted, 2.5–3 tons	None on this board (0 of 1 models have all five ratings)	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	ACC	YISO
COP at 5°F	beats 67% · 2.08MSH603E18MCAADucted, 5 tons and up	beats 75% · 2.10YOHA2-60AADucted, 3.5–4.5 tons
Capacity retention at 5°F	beats 73% · 59%MSH603E18MCAADucted, 5 tons and up	beats 72% · 83%YOHA2-60AADucted, 2.5–3 tons
HSPF2	beats 80% · 9.3MSH483E18MCAADucted, 3.5–4.5 tons	beats 92% · 9.5YOHA2-60AADucted, 3.5–4.5 tons
SEER2	beats 54% · 15.4MSH603E18MCAADucted, 5 tons and up	beats 95% · 20.5YOHA2-36AADucted, 2 tons
EER2	beats 16% · 9.0MSH603E18MCAADucted, 5 tons and up	beats 95% · 13.0YOHA2-36AADucted, 2 tons
Heating capacity at 5°F	beats 78% · 35,600 Btu/hMSH603E18MCAADucted, 5 tons and up	beats 70% · 38,500 Btu/hYOHA2-60AADucted, 3.5–4.5 tons

More comparisons

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