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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, ductless 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 Ductless, Up to 1.5 tons (under 21,000 Btu/h cooling). What size is my system?

Panasonic

  1. 1CU-XE9WKUAwith ductless indoor unit CS-XE9WKUAWPanasonic0.5 tons · 8,700 Btu/h · DuctlessKeeps 111% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    111% (Capacity at 5°F vs 47°F)
    Top 10%
    Efficiency at 5°F
    2.06 (COP at 5°F)
    Good
    Seasonal efficiency
    12.0 (HSPF2)
    Top 10%
    87.4score / 100
  2. 2CU-XE18WKUAwith ductless indoor unit CS-XE18WKUAWPanasonic1.5 tons · 17,200 Btu/h · DuctlessKeeps 102% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    102% (Capacity at 5°F vs 47°F)
    Top 10%
    Efficiency at 5°F
    2.05 (COP at 5°F)
    Good
    Seasonal efficiency
    10.9 (HSPF2)
    Great
    82.7score / 100
  3. 3CU-XE12WKUAwith ductless indoor unit CS-XE12WKUAWPanasonic1 ton · 11,500 Btu/h · DuctlessKeeps 89% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    89% (Capacity at 5°F vs 47°F)
    Great
    Efficiency at 5°F
    2.14 (COP at 5°F)
    Great
    Seasonal efficiency
    11.0 (HSPF2)
    Great
    82.1score / 100

WILLIS

  1. 1MZUHW18KCH21S2-OWILLIS1.5 tons · 17,000 Btu/h · DuctlessKeeps 76% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    76% (Capacity at 5°F vs 47°F)
    Good
    Efficiency at 5°F
    2.23 (COP at 5°F)
    Top 10%
    Seasonal efficiency
    10.0 (HSPF2)
    Good
    73.5score / 100
  2. 2HW12KUHR410A-Owith ductless indoor unit HW12KUHR410A-IWILLIS1 ton · 12,000 Btu/h · DuctlessKeeps 70% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC
    Heat kept at 5°F
    70% (Capacity at 5°F vs 47°F)
    Below the middle
    Efficiency at 5°F
    2.05 (COP at 5°F)
    Good
    Seasonal efficiency
    9.5 (HSPF2)
    Good
    55.8score / 100
  3. 3PUHW12KCH24S2-Owith ductless indoor unit PUHW12KCH24S2-IWILLIS1 ton · 12,000 Btu/h · DuctlessKeeps 75% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    75% (Capacity at 5°F vs 47°F)
    Good
    Efficiency at 5°F
    1.90 (COP at 5°F)
    Below the middle
    Seasonal efficiency
    9.0 (HSPF2)
    Below the middle
    50.0score / 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