ACC vs MAMMOTH heat pumps
Measured against models of the same size and duct type, ACC scores higher on 4 of the 6 ratings. ACC has 4 outdoor models, MAMMOTH has 4 outdoor models. ACC and MAMMOTH have no QMID on file and are not ranked.
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CompareData as of updated · 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
- MAMMOTH
- Other ranked manufacturers
Source: AHRI Directory, NEEP · as of
| Rating | ACC | MAMMOTH |
|---|---|---|
| Efficiency index | 55% (higher)median — | 39% (higher)median — |
| COP at 5°F | 67% (higher)median 2.08 | 15% (higher)median 1.80 |
| Capacity retention at 5°F | 77% (higher)median 59% | 29% (higher)median 65% |
| HSPF2 | 55% (higher)median 8.6 | 41% (higher)median 8.8 |
| SEER2 | 32%median 15.3 | 55%median 17.5 |
| EER2 | 12%median 8.6 | 43%median 10.8 |
| Heating capacity at 5°F | 79% (higher)median 35,600 Btu/h | 32% (higher)median 17,750 Btu/h |
| Outdoor models | 4 | 4 |
| AHRI certifications | 5 | 8 |
Share of models meeting each standard
| Standard | ACC | MAMMOTH |
|---|---|---|
| CEE 2025 Tier 1 (Split ASHP) | 0%0 models | 50%2 models |
| CEE 2026 Tier 1 (Split ASHP) | 0%0 models | 50%2 models |
| CEE Advanced Tier (Split ASHP) | 0%0 models | 0%0 models |
| Xcel Energy Colorado cold-climate ASHP (2025) | 0%0 models | 50%2 models |
| DOE Cold Climate Heat Pump Challenge | 0%0 models | 0%0 models |
| ENERGY STAR Cold Climate | 0%0 models | 50%2 models |
Sizes and duct types offered
Models in each peer group, with the efficiency index of those models against the rest of the group.
- ACC
- MAMMOTH
- 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
| Size and duct type | ACC | MAMMOTH |
|---|---|---|
| Ducted, 2.5–3 tons | 1 · index — | 1 · index 29% |
| Ducted, 3.5–4.5 tons | 1 · index — | 1 · index 63% |
| Ducted, 5 tons and up | 1 · index 55% | None |
| Ducted, 2 tons | None | 2 · index 49% |
| Non-ducted, 2.5–3 tons | 1 · index — | 1 · index 21% |
| Non-ducted, 2 tons | None | 1 · index 20% |
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
| Size and duct type | ACCCold-climate score, best model | MAMMOTHCold-climate score, best model |
|---|---|---|
| Ducted, 2 tons | No models in this size class | None on this board (0 of 1 models qualify) |
| Ducted, 2.5–3 tons | None on this board (0 of 1 models qualify) | 55.3(50 is the typical model of its size class)GXH24-36MSK4DHwith ducted air handler GMH**-36MSK4DH11 of 2 models qualify · AHRI 206724413 |
| Ducted, 3.5–4.5 tons | None on this board (0 of 1 models qualify) | 58.1(50 is the typical model of its size class)GXH48-60MSK4DHwith ducted air handler GMH48-**MSK4DH11 of 1 models qualify · AHRI 206724414 |
| Ducted, 5 tons and up | None on this board (0 of 1 models qualify) | No models in this size class |
| Non-ducted, 2 tons | No models in this size class | None on this board (0 of 1 models qualify) |
| Non-ducted, 2.5–3 tons | None on this board (0 of 1 models qualify) | None on this board (0 of 1 models qualify) |
All-around best
| Size and duct type | ACCAll-around score, best model | MAMMOTHAll-around score, best model |
|---|---|---|
| Ducted, 2 tons | No models in this size class | 60.8(50 is the typical model of its size class)GXH24-36MSK4DHwith ducted air handler GMH24-**MSK4DH12 of 2 models have all five ratings · AHRI 206724412 |
| Ducted, 2.5–3 tons | None on this board (0 of 1 models have all five ratings) | 29.0(50 is the typical model of its size class)V5BV-28WMAK1 of 1 models have all five ratings · AHRI 205767448 |
| Ducted, 3.5–4.5 tons | None on this board (0 of 1 models have all five ratings) | 63.3(50 is the typical model of its size class)GXH48-60MSK4DHwith ducted air handler GMH48-**MSK4DH11 of 1 models have all five ratings · AHRI 206724414 |
| 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 tons | No models in this size class | 19.8(50 is the typical model of its size class)V5BV-24WMAK1 of 1 models have all five ratings · AHRI 205767442 |
| Non-ducted, 2.5–3 tons | None on this board (0 of 1 models have all five ratings) | 21.4(50 is the typical model of its size class)V5BV-28WMAK1 of 1 models have all five ratings · AHRI 205767445 |
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.
| Rating | ACC | MAMMOTH |
|---|---|---|
| COP at 5°F | beats 67% · 2.08MSH603E18MCAADucted, 5 tons and up | beats 26% · 1.80V5BV-24WMAKNon-ducted, 2 tons |
| Capacity retention at 5°F | beats 73% · 59%MSH603E18MCAADucted, 5 tons and up | beats 73% · 81%GXH48-60MSK4DHDucted, 3.5–4.5 tons |
| HSPF2 | beats 80% · 9.3MSH483E18MCAADucted, 3.5–4.5 tons | beats 73% · 9.0GXH48-60MSK4DHDucted, 3.5–4.5 tons |
| SEER2 | beats 54% · 15.4MSH603E18MCAADucted, 5 tons and up | beats 77% · 17.0GXH48-60MSK4DHDucted, 3.5–4.5 tons |
| EER2 | beats 16% · 9.0MSH603E18MCAADucted, 5 tons and up | beats 66% · 12.0GXH24-36MSK4DHDucted, 2 tons |
| Heating capacity at 5°F | beats 78% · 35,600 Btu/hMSH603E18MCAADucted, 5 tons and up | beats 74% · 41,000 Btu/hGXH48-60MSK4DHDucted, 3.5–4.5 tons |