Dettson vs Relief Sciences heat pumps

Measured against models of the same size and duct type, Dettson and Relief Sciences split the 6 ratings 3–3. Dettson has 10 outdoor models, Relief Sciences has 10 outdoor models. Dettson and Relief Sciences 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.

Dettson and Relief Sciences 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, Dettson and Relief Sciences split the 6 ratings 3–3.

Dettson
Relief Sciences
Other ranked manufacturers

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

Average peer percentile, raw median and rank among ranked manufacturers
Rating	Dettson	Relief Sciences
Efficiency index	52%median —	66%median —
COP at 5°F	55% (higher)median 2.00	38% (higher)median 1.88
Capacity retention at 5°F	71%median 82%	72%median 88%
HSPF2	78% (higher)median 9.6	73% (higher)median 10.0
SEER2	42%median 15.4	76%median 22.3
EER2	30%median 10.6	67%median 12.5
Heating capacity at 5°F	80% (higher)median 25,000 Btu/h	67% (higher)median 18,221 Btu/h
Outdoor models	10	10
AHRI certifications	36	22

Share of models meeting each standard

Percent of each manufacturer’s models with a qualifying certification
Standard	Dettson	Relief Sciences
CEE 2025 Tier 1 (Split ASHP)	60%6 models	100%10 models
CEE 2026 Tier 1 (Split ASHP)	60%6 models	100%10 models
CEE Advanced Tier (Split ASHP)	0%0 models	0%0 models
Xcel Energy Colorado cold-climate ASHP (2025)	80%8 models	90%9 models
DOE Cold Climate Heat Pump Challenge	0%0 models	0%0 models
ENERGY STAR Cold Climate	100%10 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 · 2 groups where both have models

Dettson
Relief Sciences
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	Dettson	Relief Sciences
Ducted, up to 1.5 tons	3 · index 51%	2 · index 58%
Ducted, 2 tons	2 · index 57%	None
Ducted, 2.5–3 tons	3 · index 49%	4 · index 69%
Ducted, 3.5–4.5 tons	2 · index 53%	None
Non-ducted, up to 1.5 tons	None	6 · index 68%
Non-ducted, 2.5–3 tons	None	4 · index 64%

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	DettsonCold-climate score, best model	Relief SciencesCold-climate score, best model
Ducted, up to 1.5 tons	65.2(50 is the typical model of its size class) (higher)EVD-24-O*with ducted air handler MAC24H1418E3 of 3 models qualify · AHRI 213386698	52.0(50 is the typical model of its size class)LANG18OD35-22 of 2 models qualify · AHRI 212615019
Ducted, 2 tons	75.6(50 is the typical model of its size class)MHD-24with ducted air handler MHD-CC2.0-17.5-M2 of 2 models qualify · AHRI 210365428	No models in this size class
Ducted, 2.5–3 tons	78.6(50 is the typical model of its size class) (higher)EVD-36-Owith ducted air handler MAC36H2124E3 of 3 models qualify · AHRI 213160483	65.0(50 is the typical model of its size class)LANG27OD35-32 of 4 models qualify · AHRI 212615017
Ducted, 3.5–4.5 tons	73.8(50 is the typical model of its size class)EVD-48-Owith ducted air handler EVD-48-I2 of 2 models qualify · AHRI 210365435	No models in this size class
Non-ducted, up to 1.5 tons	No models in this size class	86.0(50 is the typical model of its size class)LANG09OD25-1with ductless indoor unit LANG09ID-256 of 6 models qualify · AHRI 210655373
Non-ducted, 2.5–3 tons	No models in this size class	76.5(50 is the typical model of its size class)LANG36OD35-43 of 4 models qualify · AHRI 212615014

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	DettsonAll-around score, best model	Relief SciencesAll-around score, best model
Ducted, up to 1.5 tons	63.4(50 is the typical model of its size class) (higher)EVD-18-Owith ducted air handler EVD-18-I3 of 3 models have all five ratings · AHRI 210365431	59.4(50 is the typical model of its size class)LANG18OD35-22 of 2 models have all five ratings · AHRI 212615019
Ducted, 2 tons	65.8(50 is the typical model of its size class)EVD-24-Owith ducted air handler EVD-24-I2 of 2 models have all five ratings · AHRI 210365432	No models in this size class
Ducted, 2.5–3 tons	68.5(50 is the typical model of its size class)EVD-36-O-Swith ducted air handler EVD-36-I3 of 3 models have all five ratings · AHRI 213488871	75.5(50 is the typical model of its size class) (higher)LANG27OD25-34 of 4 models have all five ratings · AHRI 210655379
Ducted, 3.5–4.5 tons	53.3(50 is the typical model of its size class)EVD-60-Owith ducted air handler EVD-60-I2 of 2 models have all five ratings · AHRI 210365436	No models in this size class
Non-ducted, up to 1.5 tons	No models in this size class	86.7(50 is the typical model of its size class)LANG09OD25-1with ductless indoor unit LANG09ID-256 of 6 models have all five ratings · AHRI 210655373
Non-ducted, 2.5–3 tons	No models in this size class	72.3(50 is the typical model of its size class)LANG36OD35-44 of 4 models have all five ratings · AHRI 212615014

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	Dettson	Relief Sciences
COP at 5°F	beats 79% · 2.21MHD-18Ducted, up to 1.5 tons	beats 91% · 2.25LANG12OD25-1Non-ducted, up to 1.5 tons
Capacity retention at 5°F	beats 92% · 92%EVD-48-ODucted, 3.5–4.5 tons	beats 93% · 102%LANG36OD35-4Non-ducted, 2.5–3 tons
HSPF2	beats 93% · 10.0EVD-36-ODucted, 2.5–3 tons	beats 94% · 11.6LANG09OD25-1Non-ducted, up to 1.5 tons
SEER2	beats 67% · 17.4EVD-24-ODucted, 2 tons	beats 98% · 21.0LANG27OD25-3Ducted, 2.5–3 tons
EER2	beats 72% · 12.4EVD-18-ODucted, up to 1.5 tons	beats 90% · 14.7LANG09OD25-1Non-ducted, up to 1.5 tons
Heating capacity at 5°F	beats 96% · 38,000 Btu/hEVD-36-O-SDucted, 2.5–3 tons	beats 96% · 20,000 Btu/hLANG18OD35-2Non-ducted, up to 1.5 tons

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