Skip to content
Rebate.Blue

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 5 tons and up

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, 5 tons and up (57,000 Btu/h and up cooling). What size is my system?

SLIMAIR

No ductless, 5 tons and up model from SLIMAIR.

Viessmann

No ductless, 5 tons and up model from Viessmann.

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.

Open the advanced view