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Panasonic vs WILLIS: heat pump ratings compared

Against heat pumps of the same size and type, a typical Panasonic model beats 47% and a typical WILLIS model 51%. WILLIS rates slightly higher overall.

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

Panasonic

47%

of similar heat pumps beaten by its typical model

About average

36 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°FPanasonic: Beats 40%WILLIS: Beats 39%
  • Heating power kept at 5°FCapacity at 5°F vs 47°FPanasonic: Beats 50%WILLIS: Beats 64%
  • Winter-long heating efficiencyHSPF2Panasonic: Beats 57%WILLIS: Beats 52%
  • Summer-long cooling efficiencySEER2Panasonic: Beats 48%WILLIS: Beats 55%
  • Hot-day cooling efficiencyEER2Panasonic: Beats 39%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

    Panasonic
    53%
    WILLIS
    87%

  • Xcel CC

    Panasonic
    36%
    WILLIS
    87%

  • CEE Advanced

    Panasonic
    0%
    WILLIS
    0%

  • ENERGY STAR CC

    Panasonic
    36%
    WILLIS
    73%

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?

Panasonic

  1. 1CU-HE36YAHK6with ducted air handler CS-HE36YAC6Panasonic3 tons · 35,000 Btu/h · DuctedKeeps 82% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    82% (Capacity at 5°F vs 47°F)
    Good
    Efficiency at 5°F
    2.00 (COP at 5°F)
    Good
    Seasonal efficiency
    10.0 (HSPF2)
    Top 10%
    78.6score / 100
  2. 2CU-HE30YAHK6with ducted air handler CS-HE30YAC6Panasonic2.5 tons · 30,000 Btu/h · DuctedKeeps 82% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    82% (Capacity at 5°F vs 47°F)
    Good
    Efficiency at 5°F
    1.85 (COP at 5°F)
    Below the middle
    Seasonal efficiency
    9.7 (HSPF2)
    Great
    67.8score / 100

WILLIS

  1. 1FLEX24/36KUHwith ducted air handler FLEXAH24/36KWILLIS3 tons · 34,000 Btu/h · DuctedKeeps 80% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    80% (Capacity at 5°F vs 47°F)
    Good
    Efficiency at 5°F
    1.80 (COP at 5°F)
    Below the middle
    Seasonal efficiency
    9.0 (HSPF2)
    Good
    55.3score / 100
  2. 2MZUHW30KCH21S2-OWILLIS2.5 tons · 28,400 Btu/h · DuctedKeeps 89% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC
    Heat kept at 5°F
    89% (Capacity at 5°F vs 47°F)
    Great
    Efficiency at 5°F
    1.80 (COP at 5°F)
    Below the middle
    Seasonal efficiency
    8.1 (HSPF2)
    Below the middle
    54.7score / 100
  3. 3MZUHW42KCH21S2-OWILLIS3 tons · 36,000 Btu/h · DuctedKeeps 81% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC
    Heat kept at 5°F
    81% (Capacity at 5°F vs 47°F)
    Good
    Efficiency at 5°F
    1.84 (COP at 5°F)
    Below the middle
    Seasonal efficiency
    8.1 (HSPF2)
    Below the middle
    52.1score / 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.

Open the advanced view