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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 59% and a typical Viessmann model 53%. SLIMAIR rates higher overall.

Covers older R-410A heat pumps, no longer installed new. See models sold today · Updated

SLIMAIR

59%

of similar heat pumps beaten by its typical model

Above average

54 models listed

Viessmann

53%

of similar heat pumps beaten by its typical model

About average

53 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 47%Viessmann: Beats 52%
  • Heating power kept at 5°FCapacity at 5°F vs 47°FSLIMAIR: Beats 58%Viessmann: Beats 50%
  • Winter-long heating efficiencyHSPF2SLIMAIR: Beats 71%Viessmann: Beats 63%
  • Summer-long cooling efficiencySEER2SLIMAIR: Beats 65%Viessmann: Beats 58%
  • Hot-day cooling efficiencyEER2SLIMAIR: Beats 49%Viessmann: Beats 46%

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
    67%
    Viessmann
    64%

  • Xcel CC

    SLIMAIR
    50%
    Viessmann
    43%

  • CEE Advanced

    SLIMAIR
    2%
    Viessmann
    4%

  • ENERGY STAR CC

    SLIMAIR
    43%
    Viessmann
    47%

Top cold-climate picks, ductless up to 1.5 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 Ductless, Up to 1.5 tons (under 21,000 Btu/h cooling). What size is my system?

SLIMAIR

  1. 1SHC09VE2AGwith ductless indoor unit SHM09VE2AGSLIMAIR1 ton · 9,000 Btu/h · DuctlessKeeps 86% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    86% (Capacity at 5°F vs 47°F)
    Good
    Efficiency at 5°F
    2.22 (COP at 5°F)
    Great
    Seasonal efficiency
    11.6 (HSPF2)
    Top 10%
    86.0score / 100
  2. 2SHC12VE2AGwith ductless indoor unit SHM12VE2AGSLIMAIR1 ton · 12,000 Btu/h · DuctlessKeeps 74% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    74% (Capacity at 5°F vs 47°F)
    Good
    Efficiency at 5°F
    2.25 (COP at 5°F)
    Top 10%
    Seasonal efficiency
    10.8 (HSPF2)
    Great
    77.8score / 100
  3. 3SHC18VE2AGwith ductless indoor unit SHM18VE2AGSLIMAIR1.5 tons · 18,000 Btu/h · DuctlessKeeps 71% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    71% (Capacity at 5°F vs 47°F)
    Good
    Efficiency at 5°F
    2.35 (COP at 5°F)
    Top 10%
    Seasonal efficiency
    10.5 (HSPF2)
    Great
    75.3score / 100

Viessmann

  1. 1DLCPRBH18AAKwith ductless indoor unit DLFPHBH18XAKViessmann1.5 tons · 18,000 Btu/h · DuctlessKeeps 120% of its heat at 5°FMeets CEE 2025, CEE 2026, CEE Advanced, Xcel CC, DOE CCHP, ENERGY STAR CC
    Heat kept at 5°F
    120% (Capacity at 5°F vs 47°F)
    Top 10%
    Efficiency at 5°F
    2.89 (COP at 5°F)
    Top 10%
    Seasonal efficiency
    11.0 (HSPF2)
    Great
    95.0score / 100
  2. 2DLCSRBH06AAKwith ductless indoor unit DLFSHCH06XAKViessmann0.5 tons · 6,000 Btu/h · DuctlessKeeps 107% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    107% (Capacity at 5°F vs 47°F)
    Top 10%
    Efficiency at 5°F
    2.09 (COP at 5°F)
    Great
    Seasonal efficiency
    13.6 (HSPF2)
    Top 10%
    89.3score / 100
  3. 3DLCSRBH12AAKwith ductless indoor unit DLFSFBH12XAKViessmann1 ton · 12,000 Btu/h · DuctlessKeeps 99% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    99% (Capacity at 5°F vs 47°F)
    Great
    Efficiency at 5°F
    1.99 (COP at 5°F)
    Good
    Seasonal efficiency
    10.7 (HSPF2)
    Great
    77.0score / 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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