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Willis heat pumps

36 certified models, ranked by seasonal cooling efficiency (SEER2), then heating efficiency (HSPF2), highest first.

Filters Willis
  1. 1 AUHW18KR32-OWillis
    18,600 Btu/hheating at 47°F 18,000 Btu/hcooling at 95°F

    18,000 Btu (1.5-ton) · Mini-split · 5°F 18,000 Btu/h · Cold output 97% · HSPF2 10.0 · 1 pairing

  2. 2 AUHW24KR32-OWillis
    24,000 Btu/hheating at 47°F 22,000 Btu/hcooling at 95°F

    24,000 Btu (2-ton) · Mini-split · 5°F 24,000 Btu/h · Cold output 100% · HSPF2 10.0 · 1 pairing

  3. 3 PUHW24KR32-OWillis
    24,000 Btu/hheating at 47°F 22,000 Btu/hcooling at 95°F

    24,000 Btu (2-ton) · Mini-split · 5°F 19,000 Btu/h · Cold output 79% · HSPF2 10.0 · 1 pairing

  4. 4 PUHW18KR32-OWillis
    18,000 Btu/hheating at 47°F 18,000 Btu/hcooling at 95°F

    18,000 Btu (1.5-ton) · Mini-split · 5°F 14,600 Btu/h · Cold output 81% · HSPF2 9.0 · 1 pairing

  5. 5 PUHW12KCH24S2-OWillis
    12,000 Btu/hheating at 47°F 12,000 Btu/hcooling at 95°F

    12,000 Btu (1-ton) · Mini-split · 5°F 9,000 Btu/h · Cold output 75% · HSPF2 9.0 · 1 pairing

  6. 6 AUHW09KR32-OWillis
    10,500 Btu/hheating at 47°F 9,100 Btu/hcooling at 95°F

    9,000 Btu · Mini-split · 5°F 9,200 Btu/h · Cold output 81–108% · HSPF2 9.5 · 6 pairings

  7. 7 PUHW09KR32-OWillis
    10,500 Btu/hheating at 47°F 9,100 Btu/hcooling at 95°F

    9,000 Btu · Mini-split · 5°F 9,400 Btu/h · Cold output 72–95% · HSPF2 9.5 · 6 pairings

  8. 8 PUHW12KR32-OWillis
    12,000 Btu/hheating at 47°F 12,000 Btu/hcooling at 95°F

    12,000 Btu (1-ton) · Mini-split · 5°F 10,000 Btu/h · Cold output 83–92% · HSPF2 9.3 · 6 pairings

  9. 9 AUHW12KR32-OWillis
    12,000 Btu/hheating at 47°F 12,000 Btu/hcooling at 95°F

    12,000 Btu (1-ton) · Mini-split · 5°F 10,000 Btu/h · Cold output 83–100% · HSPF2 8.8 · 6 pairings

  10. 10 PUHW18KCH23S2-OWillis
    18,000 Btu/hheating at 47°F 18,000 Btu/hcooling at 95°F

    18,000 Btu (1.5-ton) · Mini-split · 5°F 13,000 Btu/h · Cold output 72% · HSPF2 8.5 · 1 pairing

  11. 11 CHW30KR32-OWillis
    30,000 Btu/hheating at 47°F 30,000 Btu/hcooling at 95°F

    30,000 Btu (2.5-ton) · Mini-split · 5°F 23,000 Btu/h · Cold output 77% · HSPF2 9.0 · 1 pairing

  12. 12 MZUHW36KCH21S2-OWillis
    36,000 Btu/hheating at 47°F 34,000 Btu/hcooling at 95°F

    36,000 Btu (3-ton) · Mini-split · 5°F 32,400 Btu/h · Cold output 90% · HSPF2 10.0 · 1 pairing

  13. 13 MZUHW42KCH21S2-OWillis
    40,000 Btu/hheating at 47°F 36,000 Btu/hcooling at 95°F

    36,000 Btu (3-ton) · Mini-split · 5°F 32,400 Btu/h · Cold output 81% · HSPF2 10.0 · 1 pairing

  14. 14 MZUHW30KCH21S2-OWillis
    30,000 Btu/hheating at 47°F 28,400 Btu/hcooling at 95°F

    30,000 Btu (2.5-ton) · Mini-split · 5°F 22,800 Btu/h · Cold output 76% · HSPF2 10.0 · 1 pairing

  15. 15 MZUHW24KCH21S2-OWillis
    24,000 Btu/hheating at 47°F 23,200 Btu/hcooling at 95°F

    24,000 Btu (2-ton) · Mini-split · 5°F 21,600 Btu/h · Cold output 90% · HSPF2 10.0 · 1 pairing

  16. 16 MZUHW18KCH21S2-OWillis
    18,000 Btu/hheating at 47°F 17,000 Btu/hcooling at 95°F

    18,000 Btu (1.5-ton) · Mini-split · 5°F 13,600 Btu/h · Cold output 76% · HSPF2 10.0 · 1 pairing

  17. 17 CHW36KR32-OWillis
    34,000 Btu/hheating at 47°F 33,600 Btu/hcooling at 95°F

    36,000 Btu (3-ton) · Mini-split · 5°F 24,600 Btu/h · Cold output 72% · HSPF2 8.5 · 1 pairing

  18. 18 PUHW36KR32-OWillis
    34,000 Btu/hheating at 47°F 33,600 Btu/hcooling at 95°F

    36,000 Btu (3-ton) · Mini-split · 5°F 24,600 Btu/h · Cold output 72% · HSPF2 8.5 · 1 pairing

  19. 19 CHW09KAR32-OWillis
    10,000 Btu/hheating at 47°F 9,100 Btu/hcooling at 95°F

    9,000 Btu · Mini-split · 5°F 7,600 Btu/h · Cold output 76% · HSPF2 8.8 · 1 pairing

  20. 20 CHW18KR32-OWillis
    17,000 Btu/hheating at 47°F 18,000 Btu/hcooling at 95°F

    18,000 Btu (1.5-ton) · Mini-split · 5°F 12,100 Btu/h · Cold output 71% · HSPF2 8.5 · 1 pairing

  21. 21 HW-COND36KWillis
    32,000 Btu/hheating at 47°F 32,000 Btu/hcooling at 95°F

    30,000 Btu (2.5-ton) · Central · 5°F 31,000 Btu/h · Cold output 97% · HSPF2 10.5 · 1 pairing

  22. 22 FLEX48KUHR32Willis
    48,000 Btu/hheating at 47°F 48,000 Btu/hcooling at 95°F

    48,000 Btu (4-ton) · Central · 5°F 48,000 Btu/h · Cold output 100% · HSPF2 10.0 · 1 pairing

  23. 23 MZUHW42KR32-OWillis
    42,000 Btu/hheating at 47°F 42,000 Btu/hcooling at 95°F

    42,000 Btu (3.5-ton) · Mini-split · 5°F 37,000 Btu/h · Cold output 86–90% · HSPF2 9.0 · 3 pairings

  24. 24 MZUHW36KR32-OWillis
    36,000 Btu/hheating at 47°F 36,000 Btu/hcooling at 95°F

    36,000 Btu (3-ton) · Mini-split · 5°F 34,000 Btu/h · Cold output 92–100% · HSPF2 9.0 · 3 pairings

  25. 25 MZUHW30KR32-OWillis
    30,000 Btu/hheating at 47°F 28,400 Btu/hcooling at 95°F

    30,000 Btu (2.5-ton) · Mini-split · 5°F 26,400 Btu/h · Cold output 87–90% · HSPF2 9.0 · 3 pairings

  26. 26 MZUHW24KR32-OWillis
    24,000 Btu/hheating at 47°F 24,000 Btu/hcooling at 95°F

    24,000 Btu (2-ton) · Mini-split · 5°F 21,600 Btu/h · Cold output 90% · HSPF2 9.0 · 3 pairings

  27. 27 MZUHW18KR32-OWillis
    18,000 Btu/hheating at 47°F 18,000 Btu/hcooling at 95°F

    18,000 Btu (1.5-ton) · Mini-split · 5°F 13,700 Btu/h · Cold output 76–77% · HSPF2 9.0 · 3 pairings

  28. 28 CHW24KR32-OWillis
    22,400 Btu/hheating at 47°F 24,000 Btu/hcooling at 95°F

    24,000 Btu (2-ton) · Mini-split · 5°F 15,700 Btu/h · Cold output 70% · HSPF2 8.5 · 1 pairing

  29. 29 CHW12KR32-OWillis
    12,000 Btu/hheating at 47°F 12,000 Btu/hcooling at 95°F

    12,000 Btu (1-ton) · Mini-split · 5°F 9,100 Btu/h · Cold output 76% · HSPF2 8.5 · 1 pairing

  30. 30 FLEX24KUHR32Willis
    25,000 Btu/hheating at 47°F 24,000 Btu/hcooling at 95°F

    24,000 Btu (2-ton) · Central · 5°F 25,000 Btu/h · Cold output 100% · HSPF2 10.0 · 1 pairing

  31. 31 CHW12KCH18S2-OWillis
    12,000 Btu/hheating at 47°F 12,000 Btu/hcooling at 95°F

    12,000 Btu (1-ton) · Mini-split · 5°F 8,500 Btu/h · Cold output 71% · HSPF2 8.5 · 1 pairing

  32. 32 FLEX60KUHR32Willis
    48,000 Btu/hheating at 47°F 47,000 Btu/hcooling at 95°F

    48,000 Btu (4-ton) · Central · 5°F 48,000 Btu/h · Cold output 100% · HSPF2 9.5 · 4 pairings

  33. 33 FLEX36KUHR32Willis
    24,000 Btu/hheating at 47°F 23,000 Btu/hcooling at 95°F

    24,000 Btu (2-ton) · Central · 5°F 24,000 Btu/h · Cold output 91–100% · HSPF2 9.3 · 4 pairings

  34. 34 PRT60KUHWillis
    57,000 Btu/hheating at 47°F 56,000 Btu/hcooling at 95°F

    54,000 Btu (4.5-ton) · Central · 5°F 45,000 Btu/h · Cold output 79% · HSPF2 8.3 · 1 pairing

  35. 35 FLEX48/60KUHWillis
    54,000 Btu/hheating at 47°F 54,000 Btu/hcooling at 95°F

    54,000 Btu (4.5-ton) · Central · 5°F 41,000 Btu/h · Cold output 76% · HSPF2 9.0 · 1 pairing

  36. 36 FLEX24/36KUHWillis
    35,000 Btu/hheating at 47°F 34,000 Btu/hcooling at 95°F

    36,000 Btu (3-ton) · Central · 5°F 28,000 Btu/h · Cold output 80% · HSPF2 9.0 · 1 pairing

Willis heat pumps, ranked by seasonal cooling efficiency (SEER2), then heating efficiency (HSPF2)
# Model Brands Type Size At 5°FBtu/h · heating At 47°FBtu/h · heating At 95°FBtu/h · cooling Cold output% of 47°F rating COP 5°Ffull speed SEER2median pairing HSPF2Btu/Wh · median pairing Compressor Refrigerant Market Pairings
1 AUHW18KR32-O Willis Mini-split 18,000 Btu (1.5-ton)18,000 18,600 18,000 97% 1.80 27.5 10.0 Variable R-32 US CA 1
2 AUHW24KR32-O Willis Mini-split 24,000 Btu (2-ton)24,000 24,000 22,000 100% 1.80 27.0 10.0 Variable R-32 US CA 1
3 PUHW24KR32-O Willis Mini-split 24,000 Btu (2-ton)19,000 24,000 22,000 79% 1.80 26.0 10.0 Variable R-32 US CA 1
4 PUHW18KR32-O Willis Mini-split 18,000 Btu (1.5-ton)14,600 18,000 18,000 81% 1.90 24.5 9.0 Variable R-32 US CA 1
5 PUHW12KCH24S2-O Willis Mini-split 12,000 Btu (1-ton)9,000 12,000 12,000 75% 1.85 24.0 9.0 Variable R-410A US CA 1
6 AUHW09KR32-O Willis Mini-split 9,000 Btu9,200 10,500 9,100 81–108% 1.82 23.9 9.5 Variable R-32 US CA 6
7 PUHW09KR32-O Willis Mini-split 9,000 Btu9,400 10,500 9,100 72–95% 1.94 23.5 9.5 Variable R-32 US CA 6
8 PUHW12KR32-O Willis Mini-split 12,000 Btu (1-ton)10,000 12,000 12,000 83–92% 1.90 23.0 9.3 Variable R-32 US CA 6
9 AUHW12KR32-O Willis Mini-split 12,000 Btu (1-ton)10,000 12,000 12,000 83–100% 1.90 23.0 8.8 Variable R-32 US CA 6
10 PUHW18KCH23S2-O Willis Mini-split 18,000 Btu (1.5-ton)13,000 18,000 18,000 72% 1.85 23.0 8.5 Variable R-410A US CA 1
11 CHW30KR32-O Willis Mini-split 30,000 Btu (2.5-ton)23,000 30,000 30,000 77% 1.80 22.0 9.0 Variable R-32 US CA 1
12 MZUHW36KCH21S2-O Willis Mini-split 36,000 Btu (3-ton)32,400 36,000 34,000 90% 1.82 21.0 10.0 Variable R-410A US CA 1
13 MZUHW42KCH21S2-O Willis Mini-split 36,000 Btu (3-ton)32,400 40,000 36,000 81% 1.92 21.0 10.0 Variable R-410A US CA 1
14 MZUHW30KCH21S2-O Willis Mini-split 30,000 Btu (2.5-ton)22,800 30,000 28,400 76% 1.84 21.0 10.0 Variable R-410A US CA 1
15 MZUHW24KCH21S2-O Willis Mini-split 24,000 Btu (2-ton)21,600 24,000 23,200 90% 2.10 21.0 10.0 Variable R-410A US CA 1
16 MZUHW18KCH21S2-O Willis Mini-split 18,000 Btu (1.5-ton)13,600 18,000 17,000 76% 2.22 21.0 10.0 Variable R-410A US CA 1
17 CHW36KR32-O Willis Mini-split 36,000 Btu (3-ton)24,600 34,000 33,600 72% 1.80 21.0 8.5 Variable R-32 US CA 1
18 PUHW36KR32-O Willis Mini-split 36,000 Btu (3-ton)24,600 34,000 33,600 72% 1.80 21.0 8.5 Variable R-32 US CA 1
19 CHW09KAR32-O Willis Mini-split 9,000 Btu7,600 10,000 9,100 76% 1.86 20.5 8.8 Variable R-32 US CA 1
20 CHW18KR32-O Willis Mini-split 18,000 Btu (1.5-ton)12,100 17,000 18,000 71% 1.85 20.0 8.5 Variable R-32 US CA 1
21 HW-COND36K Willis Central 30,000 Btu (2.5-ton)31,000 32,000 32,000 97% 2.15 19.5 10.5 Variable R-454B CA 1
22 FLEX48KUHR32 Willis Central 48,000 Btu (4-ton)48,000 48,000 48,000 100% 2.00 19.0 10.0 Variable R-32 US CA 1
23 MZUHW42KR32-O Willis Mini-split 42,000 Btu (3.5-ton)37,000 42,000 42,000 86–90% 1.90 19.0 9.0 Variable R-32 US CA 3
24 MZUHW36KR32-O Willis Mini-split 36,000 Btu (3-ton)34,000 36,000 36,000 92–100% 1.90 19.0 9.0 Variable R-32 US CA 3
25 MZUHW30KR32-O Willis Mini-split 30,000 Btu (2.5-ton)26,400 30,000 28,400 87–90% 1.88 19.0 9.0 Variable R-32 US CA 3
26 MZUHW24KR32-O Willis Mini-split 24,000 Btu (2-ton)21,600 24,000 24,000 90% 1.86 19.0 9.0 Variable R-32 US CA 3
27 MZUHW18KR32-O Willis Mini-split 18,000 Btu (1.5-ton)13,700 18,000 18,000 76–77% 1.86 19.0 9.0 Variable R-32 US CA 3
28 CHW24KR32-O Willis Mini-split 24,000 Btu (2-ton)15,700 22,400 24,000 70% 1.75 19.0 8.5 Variable R-32 US CA 1
29 CHW12KR32-O Willis Mini-split 12,000 Btu (1-ton)9,100 12,000 12,000 76% 1.80 19.0 8.5 Variable R-32 US CA 1
30 FLEX24KUHR32 Willis Central 24,000 Btu (2-ton)25,000 25,000 24,000 100% 2.00 18.0 10.0 Variable R-32 US CA 1
31 CHW12KCH18S2-O Willis Mini-split 12,000 Btu (1-ton)8,500 12,000 12,000 71% 1.80 17.5 8.5 Variable R-410A US CA 1
32 FLEX60KUHR32 Willis Central 48,000 Btu (4-ton)48,000 48,000 47,000 100% 1.93 17.1 9.5 Variable R-32 US CA 4
33 FLEX36KUHR32 Willis Central 24,000 Btu (2-ton)24,000 24,000 23,000 91–100% 1.90 17.0 9.3 Variable R-32 US CA 4
34 PRT60KUH Willis Central 54,000 Btu (4.5-ton)45,000 57,000 56,000 79% 1.80 17.0 8.3 Variable R-410A US CA 1
35 FLEX48/60KUH Willis Central 54,000 Btu (4.5-ton)41,000 54,000 54,000 76% 1.80 16.0 9.0 Variable R-410A US CA 1
36 FLEX24/36KUH Willis Central 36,000 Btu (3-ton)28,000 35,000 34,000 80% 1.80 16.0 9.0 Variable R-410A US CA 1

The share is heat output at 5°F divided by the 47°F rating. Tests use different compressor speeds.

36 of 36 units

Other sizes

Every size class, with how many units it holds and its median heat output at 5°F