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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%

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?

DIAMONDAIR

  1. 1D2009SHO2with ductless indoor unit DF2009HMSI2DIAMONDAIR1 ton · 9,000 Btu/h · DuctlessKeeps 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
    1.90 (COP at 5°F)
    Below the middle
    Seasonal efficiency
    11.6 (HSPF2)
    Top 10%
    74.8score / 100
  2. 2D2018SHO2with ductless indoor unit DF2018HMSI2DIAMONDAIR1.5 tons · 18,000 Btu/h · DuctlessKeeps 96% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC
    Heat kept at 5°F
    96% (Capacity at 5°F vs 47°F)
    Great
    Efficiency at 5°F
    1.89 (COP at 5°F)
    Below the middle
    Seasonal efficiency
    10.6 (HSPF2)
    Great
    70.2score / 100
  3. 3D2012SHO2with ductless indoor unit DF2012HMSI2DIAMONDAIR1 ton · 12,000 Btu/h · DuctlessKeeps 92% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC
    Heat kept at 5°F
    92% (Capacity at 5°F vs 47°F)
    Great
    Efficiency at 5°F
    1.89 (COP at 5°F)
    Below the middle
    Seasonal efficiency
    10.5 (HSPF2)
    Great
    68.2score / 100

ZEPHYR

  1. 1ZE-09UH24SCOwith ductless indoor unit ZE-09UH24SCIZEPHYR1 ton · 9,000 Btu/h · DuctlessKeeps 96% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    96% (Capacity at 5°F vs 47°F)
    Great
    Efficiency at 5°F
    1.94 (COP at 5°F)
    Good
    Seasonal efficiency
    10.5 (HSPF2)
    Great
    72.9score / 100
  2. 2ZE-09CA22SEXTwith ductless indoor unit ZE-09CA22SINTZEPHYR1 ton · 9,000 Btu/h · DuctlessKeeps 80% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC
    Heat kept at 5°F
    80% (Capacity at 5°F vs 47°F)
    Good
    Efficiency at 5°F
    2.07 (COP at 5°F)
    Good
    Seasonal efficiency
    9.0 (HSPF2)
    Below the middle
    60.5score / 100
  3. 3ZE-12UH24SCOwith ductless indoor unit ZE-12UH24SCIZEPHYR1 ton · 12,000 Btu/h · DuctlessKeeps 83% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    83% (Capacity at 5°F vs 47°F)
    Good
    Efficiency at 5°F
    1.89 (COP at 5°F)
    Below the middle
    Seasonal efficiency
    9.5 (HSPF2)
    Good
    58.2score / 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.

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