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Top cold-climate picks by size

Heat pumps that keep most of their heat when it is 5°F outside, ranked on three ratings at once against units their size: how much heat they keep, how efficient they are at 5°F, and how efficient they are over a whole winter (HSPF2).

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

Showing Ductless, 3.5–4.5 tons (39,000–56,999 Btu/h cooling). What size is my system?

Top cold-climate picks, ductless 3.5–4.5 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.

264 of 479 models in this size class qualify. 164 keep less than 70% of their heat at 5°F and 41 have no 5°F heat output rating, so they cannot show it.

  1. 1LMU421HHVLG3.5 tons · 42,000 Btu/h · DuctlessKeeps 100% of its heat at 5°FMeets CEE 2025, CEE 2026, CEE Advanced, Xcel CC, DOE CCHP, ENERGY STAR CC
    Heat kept at 5°F
    100% (Capacity at 5°F vs 47°F)
    Top 10%
    Efficiency at 5°F
    2.29 (COP at 5°F)
    Top 10%
    Seasonal efficiency
    11.0 (HSPF2)
    Top 10%
    97.4score / 100
  2. 2LMU480HHVLG4 tons · 48,000 Btu/h · DuctlessKeeps 100% of its heat at 5°FMeets CEE 2025, CEE 2026, CEE Advanced, Xcel CC, DOE CCHP, ENERGY STAR CC
    Heat kept at 5°F
    100% (Capacity at 5°F vs 47°F)
    Top 10%
    Efficiency at 5°F
    2.34 (COP at 5°F)
    Top 10%
    Seasonal efficiency
    10.5 (HSPF2)
    Top 10%
    95.8score / 100
  3. 3PUMY-HP48NKMU1Mitsubishi ElectricAlso sold as Trane / Mitsubishi Electric NTXMSH48A182A; also listed as MXZ-SM48NAMHZ4 tons · 48,000 Btu/h · DuctlessKeeps 100% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC
    Heat kept at 5°F
    100% (Capacity at 5°F vs 47°F)
    Top 10%
    Efficiency at 5°F
    2.00 (COP at 5°F)
    Good
    Seasonal efficiency
    11.5 (HSPF2)
    Top 10%
    90.4score / 100
  4. 4M5OG-42HFN1-M-[X]with ductless indoor unit MSEPB-09HRFN1-MY5W(GA)Midea (sold as MDV)3.5 tons · 42,000 Btu/h · DuctlessKeeps 100% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    100% (Capacity at 5°F vs 47°F)
    Top 10%
    Efficiency at 5°F
    2.00 (COP at 5°F)
    Good
    Seasonal efficiency
    10.5 (HSPF2)
    Top 10%
    87.5score / 100
  5. 5MXZ-SM42NAMHZ2Mitsubishi ElectricAlso sold as Trane / Mitsubishi Electric NTXMSH42A152B; also listed as PUMY-HP42NKMU23.5 tons · 42,000 Btu/h · DuctlessKeeps 92% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC, ENERGY STAR CC
    Heat kept at 5°F
    92% (Capacity at 5°F vs 47°F)
    Great
    Efficiency at 5°F
    2.00 (COP at 5°F)
    Good
    Seasonal efficiency
    11.1 (HSPF2)
    Top 10%
    83.9score / 100
  6. 6LUU420HHVwith ductless indoor unit LCN429HVLG3.5 tons · 42,000 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
    2.20 (COP at 5°F)
    Top 10%
    Seasonal efficiency
    10.8 (HSPF2)
    Top 10%
    83.8score / 100
  7. 7MXZ-SM42NAMHZ***Mitsubishi ElectricAlso sold as Trane / Mitsubishi Electric NTXMSH42A152A, Trane / Mitsubishi Electric NTXMSH42A152B; also listed as MXZ-SM42NAMHZ23.5 tons · 42,000 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
    2.00 (COP at 5°F)
    Good
    Seasonal efficiency
    11.1 (HSPF2)
    Top 10%
    83.6score / 100
  8. 8RZQ42TBVJU*with ductless indoor unit FCQ42AAVJUDaikin3.5 tons · 42,000 Btu/h · DuctlessKeeps 86% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC
    Heat kept at 5°F
    86% (Capacity at 5°F vs 47°F)
    Good
    Efficiency at 5°F
    2.11 (COP at 5°F)
    Top 10%
    Seasonal efficiency
    10.2 (HSPF2)
    Great
    83.0score / 100
  9. 9MXZ-SM48NAMHZ2Mitsubishi ElectricAlso sold as Trane / Mitsubishi Electric NTXMSH48A182B; also listed as PUMY-HP48NKMU24 tons · 48,000 Btu/h · DuctlessKeeps 87% of its heat at 5°FMeets 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)
    Good
    Seasonal efficiency
    11.5 (HSPF2)
    Top 10%
    82.0score / 100
  10. 10MCY-MAP0487HS-UL*Carrier (sold as Toshiba Carrier)4 tons · 48,000 Btu/h · DuctlessKeeps 79% of its heat at 5°FMeets CEE 2025, CEE 2026, Xcel CC
    Heat kept at 5°F
    79% (Capacity at 5°F vs 47°F)
    Good
    Efficiency at 5°F
    2.60 (COP at 5°F)
    Top 10%
    Seasonal efficiency
    10.3 (HSPF2)
    Great
    82.0score / 100

These are certified test ratings, not a recommendation for your home. The right size comes from a load calculation by a contractor.

Want every qualifier’s peer percentiles and the all-sizes board? Switch to Advanced

What good looks like: ductless, 3.5–4.5 tons

Good is better than half of this size class, great is the top quarter, top is the top 10%. The scale comes from the class’s own ratings.

  • Capacity at 5°F vs 47°F

    Heating power kept at 5°F

    How much of its mild-weather heating power the unit still delivers at 5°F.

    Good
    71%+
    Great
    91%+
    Top 10%
    92%+

  • COP at 5°F

    Efficiency on a 5°F day

    How much heat the unit makes from each unit of electricity when it is 5°F outside.

    Good
    1.97+
    Great
    2.00+
    Top 10%
    2.10+

  • HSPF2

    Winter-long heating efficiency

    Heating efficiency over a whole winter, measured with a federal test.

    Good
    9.5+
    Great
    9.8+
    Top 10%
    10.5+

Next steps

The advanced view adds the all-sizes boards, each qualifier’s peer percentiles, charts of every model in each size class, and the EER2 and heat output boards.

Open the advanced view