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SUM X heat pump efficiency: 6 outdoor models compared

SUM X has 6 heat pump outdoor models certified with this refrigerant group, in 10 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 SUM X makes. SUM X has no QMID (IRS Qualified Manufacturer ID) on file, so it is not ranked against other manufacturers.

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ManufacturerData as of updated · sources

Outdoor models
6
AHRI certifications
10
Efficiency index
73%
Typical model vs same-size, same-type peers (6 models)
Meet CEE 2025
100%
6 models

How SUM X 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.
SUM X against every ranked manufacturerPeer scores, 0–100 · grey ticks: each ranked manufacturer · shaded: the middle half of SUM X’s own modelsSUM X is strongest on capacity retention at 5°F (its typical model beats 80% of comparable models) and weakest on EER2 (61%).
  • SUM X
  • Middle half of its models
  • Other ranked manufacturers
SUM X

Source: AHRI Directory, NEEP · as of

Average peer percentile of SUM X’s models
RatingBeats comparable modelsRankRaw median
Efficiency index6 models scored73%Not ranked—
COP at 5°F6 models scored78%Not ranked2.23
Capacity retention at 5°F6 models scored80%Not ranked88%
HSPF26 models scored70%Not ranked9.5
SEER26 models scored79%Not ranked19.8
EER26 models scored61%Not ranked12.0
Heating capacity at 5°F6 models scored75%Not ranked26,000 Btu/h

Standards met

Share of SUM X’s models with at least one qualifying certification
StandardShareModels
CEE 2025 Tier 1 (Split ASHP)100%6
CEE 2026 Tier 1 (Split ASHP)100%6
CEE Advanced Tier (Split ASHP)0%0
Xcel Energy Colorado cold-climate ASHP (2025)100%6
DOE Cold Climate Heat Pump Challenge0%0
ENERGY STAR Cold Climate100%6

Sizes and duct types offered

Models per peer group, and how they score against the other models of that group.
SUM X’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
  • SUM X (median, middle 50%, 10th–90th)
  • All models of the group
Ducted, 2 tons2.001,090 modelsDucted, 2.5–3 tons2.001,909 modelsDucted, 3.5–4.5 tons2.002,224 modelsDucted, 5 tons and up2.00321 modelsNon-ducted, up to 1.5 tons1.953,455 modelsmedian

Source: AHRI Directory · as of

Share of comparable models beaten, per peer group
Size and duct typeModelsIndexCOP@5°FHSPF2SEER2
Ducted, 2 tons180%85%85%88%
Ducted, 2.5–3 tons182%82%97%91%
Ducted, 3.5–4.5 tons182%94%73%87%
Ducted, 5 tons and up181%98%74%97%
Non-ducted, up to 1.5 tons256%53%46%57%

Every SUM X model in the market

SUM X’s 6 models with a known size and duct type, over the shape of the whole catalog.
SUM X models by size and ratingColoured: SUM X · grey shapes: all 14,508 models · lines: catalog medians by size
  • SUM X models
  • Ducted median by size
  • Non-ducted median by size
  • Every model at each size (width = count)
  • Standard threshold

Dots: 6 sum x models, each through its representative certification, in the colour of the rating shown. The grey shapes count all 14,508 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, sizeModels10th pct.25thMedian75th90th
Ducted, 0.5 tons8261.641.711.751.852.24
Ducted, 1 ton4071.801.902.052.412.45
Ducted, 1.5 tons9921.751.862.002.172.40
Ducted, 2 tons9991.751.862.002.182.30
Ducted, 2.5 tons1,0401.701.802.002.102.36
Ducted, 3 tons6961.801.902.002.102.42
Ducted, 3.5 tons8641.701.802.002.102.46
Ducted, 4 tons7271.801.862.002.122.40
Ducted, 4.5 tons6901.701.801.902.102.20
Ducted, 5 tons861.892.002.102.102.10
Non-ducted, 0.5 tons1,1861.751.801.902.002.22
Non-ducted, 1 ton1,3431.801.801.992.102.21
Non-ducted, 1.5 tons1,2611.801.802.002.102.31
Non-ducted, 2 tons7611.801.982.002.102.30
Non-ducted, 2.5 tons4031.801.852.002.002.10
Non-ducted, 3 tons4731.901.982.002.032.20
Non-ducted, 3.5 tons2802.002.002.002.052.10
Non-ducted, 4 tons2041.962.002.052.102.11
Non-ducted, 4.5 tons781.901.911.952.012.01
Non-ducted, 5 tons841.992.002.052.202.20

Source: AHRI Directory · as of

Top SUM X 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 SUM X 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 modelSize · typeCap. 5/47COP@5°FHSPF2Btu/h @5°FSEER2MeetsCombosAHRI ref.Compared withScore
1SM-60HSM2-CUSUM X · SMwith ducted air handler SM-60HSM2-AH5 tons57,000 Btu/h · Ducted75%2.429.042,50019.0CEE 25CEE 26XcelES CC2217747177Ducted, 5 tons and up88.7
2SM-36HSM2-CUSUM X · SMwith ducted air handler SM-36HSM2-AH2.5 tons32,000 Btu/h · Ducted97%2.1510.531,00019.5CEE 25CEE 26XcelES CC2217747175Ducted, 2.5–3 tons87.9
3SM-24HSM2-CUSUM X · SMwith ducted air handler SM-24HSM2-AH2 tons24,000 Btu/h · Ducted88%2.3010.021,00020.0CEE 25CEE 26XcelES CC2217747174Ducted, 2 tons82.1
4SM-48HSM2-CUSUM X · SMwith ducted air handler SM-48HSM2-AH4 tons48,000 Btu/h · Ducted77%2.529.037,00019.0CEE 25CEE 26XcelES CC2217747176Ducted, 3.5–4.5 tons77.3
5SM-12HSM2-CUSUM X · HiULTRAwith ductless indoor unit SM-12HSM2-WU1 ton12,000 Btu/h · Non-ducted88%2.009.510,60023.0CEE 25CEE 26XcelES CC1218457855Non-ducted, up to 1.5 tons60.1

All-around best

Top 5 SUM X 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 modelSize · typeCap. 5/47COP@5°FHSPF2SEER2EER2MeetsCombosAHRI ref.Compared withScoreHeating halfCooling halfCold-climate score
1SM-36HSM2-CUSUM X · SMwith ducted air handler SM-36HSM2-AH2.5 tons32,000 Btu/h · Ducted97%2.1510.519.511.7CEE 25CEE 26XcelES CC2217747175Ducted, 2.5–3 tons82.387.976.787.9
2SM-48HSM2-CUSUM X · SMwith ducted air handler SM-48HSM2-AH4 tons48,000 Btu/h · Ducted77%2.529.019.012.0CEE 25CEE 26XcelES CC2217747176Ducted, 3.5–4.5 tons82.377.387.477.3
3SM-60HSM2-CUSUM X · SMwith ducted air handler SM-60HSM2-AH5 tons57,000 Btu/h · Ducted75%2.429.019.011.0CEE 25CEE 26XcelES CC2217747177Ducted, 5 tons and up81.188.773.488.7
4SM-24HSM2-CUSUM X · SMwith ducted air handler SM-24HSM2-AH2 tons24,000 Btu/h · Ducted88%2.3010.020.012.0CEE 25CEE 26XcelES CC2217747174Ducted, 2 tons79.582.177.082.1
5SM-12HSM2-CUSUM X · HiULTRAwith ductless indoor unit SM-12HSM2-WU1 ton12,000 Btu/h · Non-ducted88%2.009.523.012.3CEE 25CEE 26XcelES CC1218457855Non-ducted, up to 1.5 tons60.060.159.860.1

Best model on each rating

SUM X’s model with the highest peer percentile on each rating, ranked by that one rating only
RatingModelValueCompared withBeatsAHRI ref.
COP at 5°FSM-60HSM2-CU2.42Ducted, 5 tons and up98%217747177
Capacity retention at 5°FSM-60HSM2-CU75%Ducted, 5 tons and up94%217747177
HSPF2SM-36HSM2-CU10.5Ducted, 2.5–3 tons96%217747175
SEER2SM-60HSM2-CU19.0Ducted, 5 tons and up95%217747177
EER2SM-48HSM2-CU12.0Ducted, 3.5–4.5 tons83%217747176
Heating capacity at 5°FSM-18HSM2-CU18,000 Btu/hNon-ducted, up to 1.5 tons93%218457856

All 6 SUM X models in Explore

SUM X 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.
SUM X: 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 typeCold-climate pickCold-climate score, best modelAll-around bestAll-around score, best model
Ducted, 2 tons82.1(50 is the typical model of its size class)SM-24HSM2-CUwith ducted air handler SM-24HSM2-AH1 of 1 models qualify · AHRI 21774717479.5(50 is the typical model of its size class)SM-24HSM2-CUwith ducted air handler SM-24HSM2-AH1 of 1 models have all five ratings · AHRI 217747174
Ducted, 2.5–3 tons87.9(50 is the typical model of its size class)SM-36HSM2-CUwith ducted air handler SM-36HSM2-AH1 of 1 models qualify · AHRI 21774717582.3(50 is the typical model of its size class)SM-36HSM2-CUwith ducted air handler SM-36HSM2-AH1 of 1 models have all five ratings · AHRI 217747175
Ducted, 3.5–4.5 tons77.3(50 is the typical model of its size class)SM-48HSM2-CUwith ducted air handler SM-48HSM2-AH1 of 1 models qualify · AHRI 21774717682.3(50 is the typical model of its size class)SM-48HSM2-CUwith ducted air handler SM-48HSM2-AH1 of 1 models have all five ratings · AHRI 217747176
Ducted, 5 tons and up88.7(50 is the typical model of its size class)SM-60HSM2-CUwith ducted air handler SM-60HSM2-AH1 of 1 models qualify · AHRI 21774717781.1(50 is the typical model of its size class)SM-60HSM2-CUwith ducted air handler SM-60HSM2-AH1 of 1 models have all five ratings · AHRI 217747177
Non-ducted, up to 1.5 tons60.1(50 is the typical model of its size class)SM-12HSM2-CUwith ductless indoor unit SM-12HSM2-WU2 of 2 models qualify · AHRI 21845785560.0(50 is the typical model of its size class)SM-12HSM2-CUwith ductless indoor unit SM-12HSM2-WU2 of 2 models have all five ratings · AHRI 218457855

All-around board, every manufacturer

Newest SUM X certifications

By AHRI reference number; AHRI issues references in increasing order.
The 5 most recently certified SUM X outdoor models
Outdoor modelSize · typeCOP@5°FCap. 5/47HSPF2SEER2MeetsCombosAHRI ref.
SM-18HSM2-CUSUM X · HiULTRAwith ductless indoor unit SM-18HSM2-WU1.5 tons18,000 Btu/h · Non-ducted1.90100%9.521.0CEE 25CEE 26XcelES CC1218457856
SM-12HSM2-CUSUM X · HiULTRAwith ductless indoor unit SM-12HSM2-WU1 ton12,000 Btu/h · Non-ducted2.0088%9.523.0CEE 25CEE 26XcelES CC1218457855
SM-60HSM2-CUSUM Xwith ducted air handler D(A,C,E)61C4J+TDR4.5 tons54,000 Btu/h · Ducted2.0063%8.116.0CEE 25CEE 26XcelES CC2218325241
SM-48HSM2-CUSUM Xwith ducted air handler D(A,C,E)49B3J+TDR4 tons45,000 Btu/h · Ducted1.9070%8.116.5CEE 25CEE 26XcelES CC2218325240
SM-36HSM2-CUSUM Xwith ducted air handler D(A,C,E)37D3J+TDR2.5 tons32,000 Btu/h · Ducted1.8073%8.116.5CEE 25CEE 26XcelES CC2218325239

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