BOSTON AC vs GSI heat pumps

Measured against models of the same size and duct type, BOSTON AC and GSI split the 6 ratings 3–3. BOSTON AC has 6 outdoor models, GSI has 6 outdoor models. BOSTON AC and GSI 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.

BOSTON AC and GSI 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, BOSTON AC and GSI split the 6 ratings 3–3.

BOSTON AC
GSI
Other ranked manufacturers

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

Average peer percentile, raw median and rank among ranked manufacturers
Rating	BOSTON AC	GSI
Efficiency index	56% (higher)median —	48% (higher)median —
COP at 5°F	55% (higher)median 1.99	48% (higher)median 1.93
Capacity retention at 5°F	52%median 73%	70%median 81%
HSPF2	45%median 9.0	78%median 9.6
SEER2	65% (higher)median 22.0	37% (higher)median 15.4
EER2	59% (higher)median 12.5	24% (higher)median 10.3
Heating capacity at 5°F	43%median 9,070 Btu/h	77%median 29,500 Btu/h
Outdoor models	6	6
AHRI certifications	6	8

Share of models meeting each standard

Percent of each manufacturer’s models with a qualifying certification
Standard	BOSTON AC	GSI
CEE 2025 Tier 1 (Split ASHP)	100%6 models	33.3%2 models
CEE 2026 Tier 1 (Split ASHP)	100%6 models	33.3%2 models
CEE Advanced Tier (Split ASHP)	0%0 models	0%0 models
Xcel Energy Colorado cold-climate ASHP (2025)	83.3%5 models	66.7%4 models
DOE Cold Climate Heat Pump Challenge	0%0 models	0%0 models
ENERGY STAR Cold Climate	0%0 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

BOSTON AC
GSI
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	BOSTON AC	GSI
Ducted, up to 1.5 tons	None	1 · index 52%
Ducted, 2 tons	None	1 · index 53%
Ducted, 2.5–3 tons	None	2 · index 53%
Ducted, 3.5–4.5 tons	None	2 · index 38%
Non-ducted, up to 1.5 tons	5 · index 58%	None
Non-ducted, 2 tons	1 · index 47%	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	BOSTON ACCold-climate score, best model	GSICold-climate score, best model
Ducted, up to 1.5 tons	No models in this size class	63.7(50 is the typical model of its size class)SOX430U-18HFN1-Mwith ducted air handler SAC-24HWDN1-MN01 of 1 models qualify · AHRI 214056538
Ducted, 2 tons	No models in this size class	65.5(50 is the typical model of its size class)SOD30-24HFN1-MWwith ducted air handler SVBM-24A18T3N11 of 1 models qualify · AHRI 214056539
Ducted, 2.5–3 tons	No models in this size class	78.6(50 is the typical model of its size class)SOE31U-36HFN1-Mwith ducted air handler SAC-36HWDN1-MN02 of 2 models qualify · AHRI 214056543
Ducted, 3.5–4.5 tons	No models in this size class	58.3(50 is the typical model of its size class)SOE30U-55HFN1-Mwith ducted air handler SAC-60HWDN1-MN02 of 2 models qualify · AHRI 214056545
Non-ducted, up to 1.5 tons	68.8(50 is the typical model of its size class)BA12HCT23X2Owith ductless indoor unit BA12HCT23X2I5 of 5 models qualify · AHRI 214720280	No models in this size class
Non-ducted, 2 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	BOSTON ACAll-around score, best model	GSIAll-around score, best model
Ducted, up to 1.5 tons	No models in this size class	51.6(50 is the typical model of its size class)SOX430U-18HFN1-Mwith ducted air handler SAC-24HWDN1-MN01 of 1 models have all five ratings · AHRI 214056538
Ducted, 2 tons	No models in this size class	53.2(50 is the typical model of its size class)SOD30-24HFN1-MWwith ducted air handler SVBM-24A18T3N11 of 1 models have all five ratings · AHRI 214056539
Ducted, 2.5–3 tons	No models in this size class	53.0(50 is the typical model of its size class)SOE31U-36HFN1-Mwith ducted air handler SAC-36HWDN1-MN02 of 2 models have all five ratings · AHRI 214056543
Ducted, 3.5–4.5 tons	No models in this size class	39.7(50 is the typical model of its size class)SOE30U-55HFN1-Mwith ducted air handler SAC-60HWDN1-MN02 of 2 models have all five ratings · AHRI 214056545
Non-ducted, up to 1.5 tons	70.8(50 is the typical model of its size class)BA12HCT23X2Owith ductless indoor unit BA12HCT23X2I5 of 5 models have all five ratings · AHRI 214720280	No models in this size class
Non-ducted, 2 tons	46.5(50 is the typical model of its size class)BA24HCT20X2Owith ductless indoor unit BA24HCT20X2I1 of 1 models have all five ratings · AHRI 214796637	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	BOSTON AC	GSI
COP at 5°F	beats 89% · 2.21BA18HCT22X2ONon-ducted, up to 1.5 tons	beats 76% · 2.20SOX430U-18HFN1-MDucted, up to 1.5 tons
Capacity retention at 5°F	beats 61% · 76%BA12HCT23X2ONon-ducted, up to 1.5 tons	beats 79% · 85%SOE30U-55HFN1-MDucted, 3.5–4.5 tons
HSPF2	beats 57% · 9.5BA12HCT23X2ONon-ducted, up to 1.5 tons	beats 93% · 10.0SOE31U-36HFN1-MDucted, 2.5–3 tons
SEER2	beats 73% · 23.0BA12HCT23X2ONon-ducted, up to 1.5 tons	beats 48% · 16.5SOD30-24HFN1-MWDucted, 2 tons
EER2	beats 68% · 13.0BA12HCT23X2ONon-ducted, up to 1.5 tons	beats 36% · 11.7SOX430U-18HFN1-MDucted, up to 1.5 tons
Heating capacity at 5°F	beats 73% · 12,600 Btu/hBA18HCT22X2ONon-ducted, up to 1.5 tons	beats 89% · 46,500 Btu/hSOE30U-55HFN1-MDucted, 3.5–4.5 tons

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