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iFLOW vs WILLIS: heat pump ratings compared

Against heat pumps of the same size and type, a typical iFLOW model beats 43% and a typical WILLIS model 51%. WILLIS rates higher overall.

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

iFLOW

43%

of similar heat pumps beaten by its typical model

Below average

14 models listed

WILLIS

51%

of similar heat pumps beaten by its typical model

About average

15 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°FiFLOW: Beats 44%WILLIS: Beats 39%
  • Heating power kept at 5°FCapacity at 5°F vs 47°FiFLOW: Beats 57%WILLIS: Beats 64%
  • Winter-long heating efficiencyHSPF2iFLOW: Beats 70%WILLIS: Beats 52%
  • Summer-long cooling efficiencySEER2iFLOW: Beats 36%WILLIS: Beats 55%
  • Hot-day cooling efficiencyEER2iFLOW: Beats 21%WILLIS: 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

    iFLOW
    14%
    WILLIS
    87%

  • Xcel CC

    iFLOW
    50%
    WILLIS
    87%

  • CEE Advanced

    iFLOW
    0%
    WILLIS
    0%

  • ENERGY STAR CC

    iFLOW
    0%
    WILLIS
    73%

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?

iFLOW

No ductless, 5 tons and up model from iFLOW.

WILLIS

No ductless, 5 tons and up model from WILLIS.

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