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DIAMONDAIR vs ZEPHYR: heat pump ratings compared

Against heat pumps of the same size and type, a typical DIAMONDAIR model beats 42% and a typical ZEPHYR model 58%. ZEPHYR rates higher overall.

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

DIAMONDAIR

42%

of similar heat pumps beaten by its typical model

Below average

25 models listed

ZEPHYR

58%

of similar heat pumps beaten by its typical model

Above average

25 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°FDIAMONDAIR: Beats 30%ZEPHYR: Beats 40%
  • Heating power kept at 5°FCapacity at 5°F vs 47°FDIAMONDAIR: Beats 34%ZEPHYR: Beats 68%
  • Winter-long heating efficiencyHSPF2DIAMONDAIR: Beats 42%ZEPHYR: Beats 43%
  • Summer-long cooling efficiencySEER2DIAMONDAIR: Beats 38%ZEPHYR: Beats 53%
  • Hot-day cooling efficiencyEER2DIAMONDAIR: Beats 53%ZEPHYR: Beats 52%

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

    DIAMONDAIR
    36%
    ZEPHYR
    76%

  • Xcel CC

    DIAMONDAIR
    24%
    ZEPHYR
    76%

  • CEE Advanced

    DIAMONDAIR
    0%
    ZEPHYR
    0%

  • ENERGY STAR CC

    DIAMONDAIR
    0%
    ZEPHYR
    36%

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?

DIAMONDAIR

  1. 1DF30M2Z3DIAMONDAIR2.5 tons · 28,000 Btu/h · DuctedCold-climate pick, score 57.4Meets CEE 2025, CEE 2026, Xcel CC
    Heat kept at 5°F
    71% (Capacity at 5°F vs 47°F)
    Good
    Efficiency at 5°F
    1.83 (COP at 5°F)
    Below the middle
    Winter efficiency
    9.2 (HSPF2)
    Good
    Cooling efficiency
    21.0 (SEER2)
    Top 10%
    Hot-day cooling
    11.7 (EER2)
    Good
    71.5score / 100Heating 57 · Cooling 86
  2. 2DF36M2Z4DIAMONDAIR3 tons · 36,000 Btu/h · DuctedNot a cold-climate pick: keeps 64% of its heat at 5°FMeets none of the standards tracked here
    Heat kept at 5°F
    65% (Capacity at 5°F vs 47°F)
    Below the middle
    Efficiency at 5°F
    1.68 (COP at 5°F)
    Below the middle
    Winter efficiency
    9.2 (HSPF2)
    Good
    Cooling efficiency
    20.0 (SEER2)
    Top 10%
    Hot-day cooling
    11.0 (EER2)
    Below the middle
    56.6score / 100Heating 44 · Cooling 69
  3. 3D1436HPL2DIAMONDAIR3 tons · 34,200 Btu/h · DuctedNot a cold-climate pick: keeps 33% of its heat at 5°FMeets none of the standards tracked here
    Heat kept at 5°F
    34% (Capacity at 5°F vs 47°F)
    Below the middle
    Efficiency at 5°F
    1.40 (COP at 5°F)
    Below the middle
    Winter efficiency
    6.7 (HSPF2)
    Below the middle
    Cooling efficiency
    13.4 (SEER2)
    Below the middle
    Hot-day cooling
    11.2 (EER2)
    Good
    17.3score / 100Heating 4 · Cooling 31

ZEPHYR

  1. 1ZE-36HPBwith ducted air handler AH-36BZEPHYR3 tons · 34,000 Btu/h · DuctedCold-climate pick, score 75.1Meets 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
    2.05 (COP at 5°F)
    Great
    Winter efficiency
    9.5 (HSPF2)
    Great
    Cooling efficiency
    18.0 (SEER2)
    Great
    Hot-day cooling
    10.1 (EER2)
    Below the middle
    63.2score / 100Heating 75 · Cooling 51

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