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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 68% and a typical WILLIS model 63%. Panasonic rates higher overall.

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

Panasonic

68%

of similar heat pumps beaten by its typical model

Well above average

29 models listed

WILLIS

63%

of similar heat pumps beaten by its typical model

Well above average

29 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 64%WILLIS: Beats 44%
  • Heating power kept at 5°FCapacity at 5°F vs 47°FPanasonic: Beats 72%WILLIS: Beats 71%
  • Winter-long heating efficiencyHSPF2Panasonic: Beats 80%WILLIS: Beats 50%
  • Summer-long cooling efficiencySEER2Panasonic: Beats 66%WILLIS: Beats 69%
  • Hot-day cooling efficiencyEER2Panasonic: Beats 62%WILLIS: Beats 72%

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
    97%
    WILLIS
    97%

  • Xcel CC

    Panasonic
    90%
    WILLIS
    97%

  • CEE Advanced

    Panasonic
    21%
    WILLIS
    10%

  • ENERGY STAR CC

    Panasonic
    79%
    WILLIS
    86%

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

Panasonic

  1. 1CU-YM9CBUCwith ducted air handler CS-YM9CD2UWPanasonic1 ton · 9,000 Btu/h · DuctedKeeps 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
    2.25 (COP at 5°F)
    Great
    Seasonal efficiency
    11.0 (HSPF2)
    Top 10%
    80.1score / 100
  2. 2CU-HM18BAHUwith ducted air handler CS-HM24BAAU1Panasonic1.5 tons · 18,000 Btu/h · DuctedKeeps 95% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    95% (Capacity at 5°F vs 47°F)
    Great
    Efficiency at 5°F
    2.06 (COP at 5°F)
    Good
    Seasonal efficiency
    9.5 (HSPF2)
    Good
    72.8score / 100
  3. 3CU-YM12CBUCwith ducted air handler CS-YM12CD2UWPanasonic1 ton · 11,500 Btu/h · DuctedKeeps 73% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    73% (Capacity at 5°F vs 47°F)
    Below the middle
    Efficiency at 5°F
    2.24 (COP at 5°F)
    Great
    Seasonal efficiency
    10.2 (HSPF2)
    Great
    71.6score / 100

WILLIS

  1. 1PUHW09KR32-Owith ducted air handler WHEDT09KWILLIS1 ton · 9,100 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)
    Great
    Efficiency at 5°F
    2.14 (COP at 5°F)
    Great
    Seasonal efficiency
    9.2 (HSPF2)
    Good
    69.9score / 100
  2. 2AUHW18KR32-Owith ducted air handler WHEDT18KWILLIS1.5 tons · 18,000 Btu/h · DuctedKeeps 94% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC
    Heat kept at 5°F
    94% (Capacity at 5°F vs 47°F)
    Great
    Efficiency at 5°F
    1.80 (COP at 5°F)
    Below the middle
    Seasonal efficiency
    9.4 (HSPF2)
    Good
    59.4score / 100
  3. 3AUHW09KR32-Owith ducted air handler WHEDT09KWILLIS1 ton · 9,100 Btu/h · DuctedKeeps 88% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    88% (Capacity at 5°F vs 47°F)
    Good
    Efficiency at 5°F
    1.80 (COP at 5°F)
    Below the middle
    Seasonal efficiency
    9.5 (HSPF2)
    Good
    55.7score / 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