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SLIMAIR vs Viessmann: heat pump ratings compared

Against heat pumps of the same size and type, a typical SLIMAIR model beats 60% and a typical Viessmann model 60%. They are level.

Covers heat pumps sold new today (R-454B and R-32 refrigerant). See older R-410A models · Updated

SLIMAIR

60%

of similar heat pumps beaten by its typical model

Well above average

48 models listed

Viessmann

60%

of similar heat pumps beaten by its typical model

Well above average

43 models listed

Rating by ratingEach bar is the share of same-size, same-type heat pumps that a typical model beats, so the two brands compare fairly even if they make different sizes.
  • Efficiency on a 5°F dayCOP at 5°FSLIMAIR: Beats 60%Viessmann: Beats 53%
  • Heating power kept at 5°FCapacity at 5°F vs 47°FSLIMAIR: Beats 59%Viessmann: Beats 72%
  • Winter-long heating efficiencyHSPF2SLIMAIR: Beats 73%Viessmann: Beats 74%
  • Summer-long cooling efficiencySEER2SLIMAIR: Beats 61%Viessmann: Beats 59%
  • Hot-day cooling efficiencyEER2SLIMAIR: Beats 53%Viessmann: Beats 49%

Average (50%)Dashed outline: the other brand, for comparison

Want ranks, distributions per size class and cold-weather curves? Switch to Advanced

Rebate standards

Share of each brand’s models that meet the level. Programs can have other rules too.

  • CEE 2025

    SLIMAIR
    90%
    Viessmann
    84%

  • Xcel CC

    SLIMAIR
    77%
    Viessmann
    79%

  • CEE Advanced

    SLIMAIR
    2%
    Viessmann
    5%

  • ENERGY STAR CC

    SLIMAIR
    79%
    Viessmann
    70%

Top cold-climate picks, ducted 2.5–3 tons

Only units that keep at least 70% of their heat at 5°F, ranked on heat kept, efficiency at 5°F and seasonal efficiency (HSPF2), against units their size.

Showing Ducted, 2.5–3 tons (27,000–38,999 Btu/h cooling). What size is my system?

SLIMAIR

  1. 1SHC36AH2AGwith ducted air handler SHD36AC2AGSLIMAIR3 tons · 36,000 Btu/h · DuctedKeeps 90% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    90% (Capacity at 5°F vs 47°F)
    Good
    Efficiency at 5°F
    2.10 (COP at 5°F)
    Great
    Seasonal efficiency
    11.1 (HSPF2)
    Top 10%
    83.2score / 100
  2. 2SHC5Z36AH2AGSLIMAIR3 tons · 36,000 Btu/h · DuctedKeeps 106% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    106% (Capacity at 5°F vs 47°F)
    Top 10%
    Efficiency at 5°F
    2.00 (COP at 5°F)
    Good
    Seasonal efficiency
    10.4 (HSPF2)
    Top 10%
    82.5score / 100
  3. 3SHC36AH224Vwith ducted air handler SHV36AE2AGSLIMAIR3 tons · 36,000 Btu/h · DuctedKeeps 105% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    105% (Capacity at 5°F vs 47°F)
    Top 10%
    Efficiency at 5°F
    1.90 (COP at 5°F)
    Below the middle
    Seasonal efficiency
    10.3 (HSPF2)
    Top 10%
    73.1score / 100

Viessmann

  1. 1D5CMHAH36EAKViessmann3 tons · 36,000 Btu/h · DuctedKeeps 106% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    106% (Capacity at 5°F vs 47°F)
    Top 10%
    Efficiency at 5°F
    2.00 (COP at 5°F)
    Good
    Seasonal efficiency
    10.5 (HSPF2)
    Top 10%
    83.2score / 100
  2. 2D5CLHAH36AAKwith ducted air handler D5FLDAH36XHKViessmann3 tons · 36,000 Btu/h · DuctedKeeps 90% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    90% (Capacity at 5°F vs 47°F)
    Good
    Efficiency at 5°F
    2.10 (COP at 5°F)
    Great
    Seasonal efficiency
    11.1 (HSPF2)
    Top 10%
    83.2score / 100
  3. 3D5CMHAH30EAKViessmann2.5 tons · 30,000 Btu/h · DuctedKeeps 116% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    116% (Capacity at 5°F vs 47°F)
    Top 10%
    Efficiency at 5°F
    1.95 (COP at 5°F)
    Below the middle
    Seasonal efficiency
    10.5 (HSPF2)
    Top 10%
    78.5score / 100

These are certified test ratings, not a recommendation for your home. The right size comes from a load calculation by a contractor.

Next steps

The advanced view adds ranks, both brands’ models inside every size class, standout models per rating and cold-weather curves.

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