COMFORTSTAR vs ZERO: heat pump ratings compared
Against heat pumps of the same size and type, a typical COMFORTSTAR model beats 50% and a typical ZERO model 53%. ZERO rates slightly higher overall.
Covers heat pumps sold new today (R-454B and R-32 refrigerant). See older R-410A models · Updated
COMFORTSTAR
50%
of similar heat pumps beaten by its typical model
About average133 models listed
ZERO
53%
of similar heat pumps beaten by its typical model
About average119 models listed
- Efficiency on a 5°F dayCOP at 5°FCOMFORTSTAR: Beats 51%ZERO: Beats 45%
- Heating power kept at 5°FCapacity at 5°F vs 47°FCOMFORTSTAR: Beats 48%ZERO: Beats 52%
- Winter-long heating efficiencyHSPF2COMFORTSTAR: Beats 54%ZERO: Beats 57%
- Summer-long cooling efficiencySEER2COMFORTSTAR: Beats 49%ZERO: Beats 58%
- Hot-day cooling efficiencyEER2COMFORTSTAR: Beats 44%ZERO: Beats 48%
Average (50%)Dashed outline: the other brand, for comparison
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Rebate standards
CEE 2025
- COMFORTSTAR
- 53%
- ZERO
- 71%
Xcel CC
- COMFORTSTAR
- 47%
- ZERO
- 65%
CEE Advanced
- COMFORTSTAR
- 2%
- ZERO
- 0%
ENERGY STAR CC
- COMFORTSTAR
- 30%
- ZERO
- 53%
All-around best, ductless 3.5–4.5 tons
Balances heating (5°F output and efficiency, HSPF2) and cooling (SEER2, EER2), each rating against units their size.
Showing Ductless, 3.5–4.5 tons (39,000–56,999 Btu/h cooling). What size is my system?
COMFORTSTAR
- 1CVH3-60-6SHCOMFORTSTAR4.5 tons · 51,000 Btu/h · DuctlessCold-climate pick, score 69.9Meets 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
- 2.00 (COP at 5°F)
- Below the middle
- Winter efficiency
- 10.6 (HSPF2)
- Good
- Cooling efficiency
- 21.4 (SEER2)
- Good
- Hot-day cooling
- 12.0 (EER2)
- Good
- 2CVH3-48-6SHCOMFORTSTAR4 tons · 45,000 Btu/h · DuctlessCold-climate pick, score 68.7Meets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
- Heat kept at 5°F
- 98% (Capacity at 5°F vs 47°F)
- Top 10%
- Efficiency at 5°F
- 2.00 (COP at 5°F)
- Below the middle
- Winter efficiency
- 10.2 (HSPF2)
- Good
- Cooling efficiency
- 21.2 (SEER2)
- Good
- Hot-day cooling
- 12.0 (EER2)
- Good
- 3CMZ3-55-6ZCOMFORTSTAR4 tons · 45,000 Btu/h · DuctlessCold-climate pick, score 60.1Meets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
- Heat kept at 5°F
- 78% (Capacity at 5°F vs 47°F)
- Below the middle
- Efficiency at 5°F
- 2.10 (COP at 5°F)
- Great
- Winter efficiency
- 10.3 (HSPF2)
- Good
- Cooling efficiency
- 20.9 (SEER2)
- Below the middle
- Hot-day cooling
- 11.9 (EER2)
- Good
ZERO
- 1Z4SOV-53HDMB-USHHZERO4.5 tons · 51,000 Btu/h · DuctlessCold-climate pick, score 69.9Meets 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
- 2.00 (COP at 5°F)
- Below the middle
- Winter efficiency
- 10.6 (HSPF2)
- Good
- Cooling efficiency
- 21.4 (SEER2)
- Good
- Hot-day cooling
- 12.0 (EER2)
- Good
- 2Z4SOV-48HDMB-USHHZERO4 tons · 45,000 Btu/h · DuctlessCold-climate pick, score 68.7Meets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
- Heat kept at 5°F
- 98% (Capacity at 5°F vs 47°F)
- Top 10%
- Efficiency at 5°F
- 2.00 (COP at 5°F)
- Below the middle
- Winter efficiency
- 10.2 (HSPF2)
- Good
- Cooling efficiency
- 21.2 (SEER2)
- Good
- Hot-day cooling
- 12.0 (EER2)
- Good
- 3Z4SOV-48HDMB-USZEROAlso listed as Z6SOV-48HDMB-US4 tons · 45,000 Btu/h · DuctlessCold-climate pick, score 60.1Meets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
- Heat kept at 5°F
- 78% (Capacity at 5°F vs 47°F)
- Below the middle
- Efficiency at 5°F
- 2.10 (COP at 5°F)
- Great
- Winter efficiency
- 10.3 (HSPF2)
- Good
- Cooling efficiency
- 20.9 (SEER2)
- Below the middle
- Hot-day cooling
- 11.9 (EER2)
- Good
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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