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Nortek Global HVAC vs ZERO heat pumps

Measured against models of the same size and duct type, ZERO scores higher on 6 of the 6 ratings. Nortek Global HVAC has 109 outdoor models, ZERO has 119 outdoor models. ZERO has no QMID on file and is not ranked.

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CompareData as of updated · sources

Against comparable models

Each cell is the share of same-size, same-type models that the manufacturer’s typical model beats (50% is typical); the higher score is in bold. Raw medians are underneath for context: they depend on which sizes each one makes, so they are not compared.
Nortek Global HVAC and ZERO on every ratingPeer scores, 0–100 · grey ticks: every ranked manufacturer · shaded: the middle half of each one’s modelsMeasured against models of the same size and duct type, ZERO scores higher on 6 of the 6 ratings.
  • Nortek Global HVAC
  • ZERO
  • Other ranked manufacturers
Nortek G…ZERO

Source: AHRI Directory, NEEP · as of

Average peer percentile, raw median and rank among ranked manufacturers
RatingNortek Global HVACZERO
Efficiency index31%median — · 29th ranked53%median —
COP at 5°F23%median 1.75 · 29th ranked45%median 1.94
Capacity retention at 5°F28%median 49% · 29th ranked52%median 74%
HSPF228%median 7.5 · 29th ranked57%median 9.5
SEER232%median 14.3 · 29th ranked58%median 19.0
EER242%median 11.0 · 22nd ranked48%median 11.7
Heating capacity at 5°F28%median 16,200 Btu/h · 29th ranked55%median 18,750 Btu/h
Outdoor models109119
AHRI certifications781164

Share of models meeting each standard

Percent of each manufacturer’s models with a qualifying certification
StandardNortek Global HVACZERO
CEE 2025 Tier 1 (Split ASHP)28.4%31 models70.6%84 models
CEE 2026 Tier 1 (Split ASHP)24.8%27 models69.7%83 models
CEE Advanced Tier (Split ASHP)1.8%2 models0%0 models
Xcel Energy Colorado cold-climate ASHP (2025)20.2%22 models64.7%77 models
DOE Cold Climate Heat Pump Challenge1.8%2 models0%0 models
ENERGY STAR Cold Climate11%12 models52.9%63 models

Sizes and duct types offered

Models in each peer group, with the efficiency index of those models against the rest of the group.
Side by side, inside each size and duct typeShape: every model of the group · bars: each manufacturer’s middle half, median dot, 10th–90th line · 9 groups where both have models
  • Nortek Global HVAC
  • ZERO
  • All models of the group
Ducted, up to 1.5 tons1.901,783 modelsDucted, 2 tons2.001,090 modelsDucted, 2.5–3 tons2.001,909 modelsDucted, 3.5–4.5 tons2.002,224 modelsDucted, 5 tons and up2.00321 modelsNon-ducted, up to 1.5 tons1.953,455 modelsNon-ducted, 2 tons2.00863 modelsNon-ducted, 2.5–3 tons2.001,106 modelsNon-ducted, 3.5–4.5 tons2.00564 modelsNon-ducted, 5 tons and up2.0585 modelsmedian

Raw ratings are only placed side by side within one size and duct type, where they are comparable.

Source: AHRI Directory · as of

Models per peer group · efficiency index within the group
Size and duct typeNortek Global HVACZERO
Ducted, up to 1.5 tons6 · index 25%7 · index 68%
Ducted, 2 tons15 · index 25%13 · index 51%
Ducted, 2.5–3 tons28 · index 25%20 · index 54%
Ducted, 3.5–4.5 tons38 · index 30%26 · index 54%
Ducted, 5 tons and up4 · index 18%2 · index 64%
Non-ducted, up to 1.5 tons12 · index 44%39 · index 53%
Non-ducted, 2 tons4 · index 50%9 · index 50%
Non-ducted, 2.5–3 tons6 · index 42%13 · index 45%
Non-ducted, 3.5–4.5 tons1 · index 68%6 · index 52%
Non-ducted, 5 tons and upNone2 · index 27%

Cold-climate and all-around picks, size class by size class

Each manufacturer’s best model on each board in every size and duct type, side by side; the higher score is in bold. Both scores are 0–100 against every model of that size class (the line on each bar is 50, the typical model there), so the two compare fairly even when they make different sizes.

Cold-climate picks

Best cold-climate pick per size and duct type (keeps at least 70% of its heat at 5°F). Qualifies when its capacity retention at 5°F (capacity at 5°F as a share of capacity at 47°F) is at least 70% and Capacity retention at 5°F, COP at 5°F, HSPF2 are all rated. Score = the equal-weight mean of its peer percentiles on Capacity retention at 5°F, COP at 5°F, HSPF2 (share of the other models in its peer group it beats, 0–100), all from one certified pairing: in each duct type a model is sold in, its qualifying pairing of that type with the best score; equal scores (one decimal) go to the higher heating capacity at 5°F.
Size and duct typeNortek Global HVACCold-climate score, best modelZEROCold-climate score, best model
Ducted, up to 1.5 tons39.3(50 is the typical model of its size class)DXH18FMK3IH1 of 6 models qualify · AHRI 21574631572.6(50 is the typical model of its size class) (higher)Z4SOV-18HDMB-USAlso listed as Z3SOV-18HDMB-US5 of 7 models qualify · AHRI 217138401
Ducted, 2 tons49.0(50 is the typical model of its size class)DXH24FMK3IH1 of 14 models qualify · AHRI 21574631770.4(50 is the typical model of its size class) (higher)ZRRV07HPBYFC-18SAlso listed as ZPRVO7HPBYFC-18S, ZPRV07HPBYFC-18S11 of 13 models qualify · AHRI 217904930
Ducted, 2.5–3 tons76.9(50 is the typical model of its size class)UXH24-36MSK3IHwith ducted air handler UMD36MSK3IH3 of 29 models qualify · AHRI 21713820782.5(50 is the typical model of its size class) (higher)Z4SOV-36HDMB-USHH13 of 20 models qualify · AHRI 217752806
Ducted, 3.5–4.5 tons85.1(50 is the typical model of its size class) (higher)UXH48-60MSK3IHwith ducted air handler UMD60MSK3IH2 of 38 models qualify · AHRI 21713820982.7(50 is the typical model of its size class)Z4SOV-48HDMB-USHH19 of 26 models qualify · AHRI 217752809
Ducted, 5 tons and upNone on this board (0 of 4 models qualify)None on this board (0 of 2 models qualify)
Non-ducted, up to 1.5 tons66.8(50 is the typical model of its size class)WHS18SZB21Swith ductless indoor unit WHS18WMB21S10 of 12 models qualify · AHRI 21710198185.9(50 is the typical model of its size class) (higher)ZMSB-09HV-USHHR2-Owith ductless indoor unit ZMSB-09HV-USHHR2-I31 of 39 models qualify · AHRI 216097679
Non-ducted, 2 tons67.5(50 is the typical model of its size class)DXH24FMK3IH4 of 4 models qualify · AHRI 21574631177.2(50 is the typical model of its size class) (higher)ZMSB-24HV-USHHCR2-Owith ductless indoor unit ZMSB-24HV-USHHCR2-I7 of 9 models qualify · AHRI 216097676
Non-ducted, 2.5–3 tons77.2(50 is the typical model of its size class) (higher)DXH36FMK3IH5 of 6 models qualify · AHRI 21574631372.6(50 is the typical model of its size class)Z4SOV-36HDMB-USHH9 of 13 models qualify · AHRI 217752807
Non-ducted, 3.5–4.5 tons66.5(50 is the typical model of its size class)DXH42FMK3IH1 of 1 models qualify · AHRI 21574631469.9(50 is the typical model of its size class) (higher)Z4SOV-53HDMB-USHH6 of 6 models qualify · AHRI 217752813
Non-ducted, 5 tons and upNo models in this size classNone on this board (0 of 2 models qualify)

All-around best

Best all-around model per size and duct type. Score = 50% heating, the mean of its peer percentiles on COP at 5°F, Capacity retention at 5°F, HSPF2, plus 50% cooling, the mean of its peer percentiles on SEER2 and EER2 (share of the other models in its peer group it beats, 0–100). All five ratings are required; there is no minimum heat kept at 5°F. In each duct type a model is sold in, it is scored on its pairing of that type with the best score; equal scores (one decimal) go to the higher cold-climate score, then the higher heating capacity at 5°F.
Size and duct typeNortek Global HVACAll-around score, best modelZEROAll-around score, best model
Ducted, up to 1.5 tons48.6(50 is the typical model of its size class)DXH18FMK3IH6 of 6 models have all five ratings · AHRI 21574631577.4(50 is the typical model of its size class) (higher)Z4SOV-18HDMB-USHH6 of 7 models have all five ratings · AHRI 217752800
Ducted, 2 tons72.4(50 is the typical model of its size class)UXH24-36MSK3IHwith ducted air handler UMD24MSK3IH15 of 15 models have all five ratings · AHRI 21713820679.6(50 is the typical model of its size class) (higher)ZOV-24HDGBwith ducted air handler ZAV-24HDGB12 of 13 models have all five ratings · AHRI 217619841
Ducted, 2.5–3 tons61.6(50 is the typical model of its size class)DXH30FMK3IH25 of 28 models have all five ratings · AHRI 21574631883.6(50 is the typical model of its size class) (higher)Z4SOV-36HDMB-USHH18 of 20 models have all five ratings · AHRI 217752806
Ducted, 3.5–4.5 tons83.1(50 is the typical model of its size class)UXH48-60MSK3IHwith ducted air handler UMD48MSK3IH35 of 38 models have all five ratings · AHRI 21713820885.1(50 is the typical model of its size class) (higher)Z4SOV-48HDMB-USAlso listed as Z6SOV-48HDMB-US23 of 26 models have all five ratings · AHRI 217138410
Ducted, 5 tons and up17.9(50 is the typical model of its size class)RHPXYB060AJT1 of 4 models have all five ratings · AHRI 21746914964.7(50 is the typical model of its size class) (higher)Z4SOV-60HDMB-US2 of 2 models have all five ratings · AHRI 217138413
Non-ducted, up to 1.5 tons78.0(50 is the typical model of its size class)DXH09PSK3IHwith ductless indoor unit DHH09PUK3IH12 of 12 models have all five ratings · AHRI 21601176786.7(50 is the typical model of its size class) (higher)ZMSB-09HV-USHHR2-Owith ductless indoor unit ZMSB-09HV-USHHR2-I39 of 39 models have all five ratings · AHRI 216097679
Non-ducted, 2 tons72.2(50 is the typical model of its size class)DXH24PSK3IHwith ductless indoor unit DHH24PUK3IH4 of 4 models have all five ratings · AHRI 21601177174.3(50 is the typical model of its size class) (higher)ZMSB-24HV-USHHR2-Owith ductless indoor unit ZMSB-24HV-USHHR2-I9 of 9 models have all five ratings · AHRI 216097682
Non-ducted, 2.5–3 tons70.5(50 is the typical model of its size class) (higher)DXH30FMK3IH6 of 6 models have all five ratings · AHRI 21574631266.3(50 is the typical model of its size class)Z4SOV-36HDMB-USHH13 of 13 models have all five ratings · AHRI 217752805
Non-ducted, 3.5–4.5 tons67.7(50 is the typical model of its size class) (higher)DXH42FMK3IH1 of 1 models have all five ratings · AHRI 21574631462.6(50 is the typical model of its size class)Z4SOV-53HDMB-USHH6 of 6 models have all five ratings · AHRI 217752811
Non-ducted, 5 tons and upNo models in this size class32.5(50 is the typical model of its size class)Z4SOV-60HDMB-USAlso listed as Z6SOV-60HDMB-US2 of 2 models have all five ratings · AHRI 217138412

All-around board, every manufacturer

Standout model on each rating

Each manufacturer’s model that beats the largest share of comparable models on the rating; the higher share is in bold.
Top model per rating by peer percentile, with its AHRI-certified value and peer group
RatingNortek Global HVACZERO
COP at 5°Fbeats 100% · 2.53WHS18SZB21SNon-ducted, up to 1.5 tonsbeats 99% · 2.80ZOU-42HDCA-S14Ducted, 3.5–4.5 tons
Capacity retention at 5°Fbeats 99% · 114%UXH48-60MSK3IHDucted, 3.5–4.5 tonsbeats 97% · 103%ZRRV07HPBYFC-18SAlso listed as ZPRVO7HPBYFC-18S, ZPRV07HPBYFC-18SDucted, 2 tons
HSPF2beats 90% · 10.5UXH48-60MSK3IHDucted, 3.5–4.5 tonsbeats 99% · 11.0Z4SOV-48HDMB-USHHDucted, 3.5–4.5 tons
SEER2beats 97% · 26.0DXH24PSK3IHNon-ducted, 2 tonsbeats 99% · 22.0Z3SOV-27HDTB-USDucted, 2.5–3 tons
EER2beats 94% · 13.0DXH42FMK3IHNon-ducted, 3.5–4.5 tonsbeats 93% · 13.3ZOV-24HDGBDucted, 2 tons
Heating capacity at 5°Fbeats 98% · 54,000 Btu/hUXH48-60MSK3IHDucted, 3.5–4.5 tonsbeats 97% · 39,000 Btu/hZSOVA-36HDMB-USHHDucted, 2.5–3 tons

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