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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%

All-around best, ducted 2.5–3 tons

Balances heating (5°F output and efficiency, HSPF2) and cooling (SEER2, EER2), each rating against units their size.

Showing Ducted, 2.5–3 tons (27,000–38,999 Btu/h cooling), the most-listed ducted size. Pick yours above. What size is my system?

Panasonic

  1. 1CU-5YM36CBUCPanasonic3 tons · 36,000 Btu/h · DuctedCold-climate pick, score 83.1Meets CEE 2025, CEE 2026, Xcel CC
    Heat kept at 5°F
    106% (Capacity at 5°F vs 47°F)
    Top 10%
    Efficiency at 5°F
    2.00 (COP at 5°F)
    Good
    Winter efficiency
    10.4 (HSPF2)
    Top 10%
    Cooling efficiency
    19.4 (SEER2)
    Great
    Hot-day cooling
    12.0 (EER2)
    Great
    84.0score / 100Heating 83 · Cooling 85
  2. 2CU-4YM27CBUCPanasonic2.5 tons · 28,000 Btu/h · DuctedCold-climate pick, score 73.3Meets CEE 2025, CEE 2026, Xcel CC
    Heat kept at 5°F
    96% (Capacity at 5°F vs 47°F)
    Great
    Efficiency at 5°F
    2.00 (COP at 5°F)
    Good
    Winter efficiency
    9.5 (HSPF2)
    Great
    Cooling efficiency
    19.0 (SEER2)
    Great
    Hot-day cooling
    12.0 (EER2)
    Great
    77.7score / 100Heating 73 · Cooling 82
  3. 3CU-HM36BAHUwith ducted air handler CS-HM36BAHUPanasonic3 tons · 36,000 Btu/h · DuctedCold-climate pick, score 73.1Meets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    105% (Capacity at 5°F vs 47°F)
    Top 10%
    Efficiency at 5°F
    1.90 (COP at 5°F)
    Below the middle
    Winter efficiency
    10.3 (HSPF2)
    Top 10%
    Cooling efficiency
    17.4 (SEER2)
    Good
    Hot-day cooling
    11.7 (EER2)
    Good
    67.3score / 100Heating 73 · Cooling 62

WILLIS

  1. 1HW-COND36Kwith ducted air handler HW-AHU36KWILLIS2.5 tons · 32,000 Btu/h · DuctedCold-climate pick, score 87.9Meets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    97% (Capacity at 5°F vs 47°F)
    Great
    Efficiency at 5°F
    2.15 (COP at 5°F)
    Great
    Winter efficiency
    10.5 (HSPF2)
    Top 10%
    Cooling efficiency
    19.5 (SEER2)
    Top 10%
    Hot-day cooling
    11.7 (EER2)
    Good
    82.3score / 100Heating 88 · Cooling 77
  2. 2MZUHW30KR32-OWILLIS2.5 tons · 28,400 Btu/h · DuctedCold-climate pick, score 48.2Meets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    87% (Capacity at 5°F vs 47°F)
    Good
    Efficiency at 5°F
    1.88 (COP at 5°F)
    Below the middle
    Winter efficiency
    8.1 (HSPF2)
    Below the middle
    Cooling efficiency
    18.0 (SEER2)
    Good
    Hot-day cooling
    12.0 (EER2)
    Great
    61.6score / 100Heating 48 · Cooling 75
  3. 3MZUHW36KR32-OWILLIS3 tons · 36,000 Btu/h · DuctedCold-climate pick, score 52.2Meets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    92% (Capacity at 5°F vs 47°F)
    Great
    Efficiency at 5°F
    1.90 (COP at 5°F)
    Below the middle
    Winter efficiency
    8.1 (HSPF2)
    Below the middle
    Cooling efficiency
    18.0 (SEER2)
    Good
    Hot-day cooling
    11.7 (EER2)
    Good
    59.0score / 100Heating 52 · Cooling 66

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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