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      2-ton central heat pump · ZAVA Series

      ZERO ZSOVA-24HDMB-USHH

      Very good cooling and heating efficiency for a 2-ton central heat pump, and certified for cold climates.

      Ranks #127 of 331 2 ton central heat pumps for cooling efficiency, and costs about $644 a year to run in a mixed climate like Atlanta.

      SEER2
      18.3 Cooling efficiency over a season
      Very good · beats 74%
      HSPF2
      10.0 Heating efficiency over a season
      Very good · beats 84%
      EER2
      11.7 Cooling efficiency on a 95°F day
      Average · beats 43%
      Heat at 5°F
      21,600 BTU/h90% of its 47°F output
      Below average · beats 14%

      A good fit if…

      • You want low cooling bills - its SEER2 beats 74% of central heat pumps.
      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 21,600 BTU/h at 5°F.
      • It will heat most of the year - its HSPF2 beats 84% of central heat pumps.
      • You want steady temperatures and quiet running - the compressor varies its speed.

      Think twice if…

      • Nothing stands out - its ratings have no weak spot for its class.

      Calculate my running cost

      Details

      Specifications2 ton, R-454B
      General
      BrandZERO
      Also sold asSLIMAIR, ECOER
      Outdoor unit modelZSOVA-24HDMB-USHH
      SeriesZAVA Series
      TypeCentral heat pump
      Nominal size2 ton
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-454B
      Connected (smart) capableNo
      On the market sinceFebruary 10, 2025
      Last certifiedSeptember 30, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better18.3 (range 18.3)
      EER2Efficiency at 95°F outdoors11.7
      Cooling capacity23,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better10.0
      Capacity at 47°F24,000 BTU/h
      Capacity at 17°F20,800 BTU/h
      Capacity at 5°F21,600 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater1.87
      ENERGY STAR cold climateYes
      Heating output as it gets colder90% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with ZAVA-24HDMB-US at the standard test temperatures, in BTU/h:

      Certified matchups1 indoor units

      The same outdoor unit scores differently with each indoor unit. Ask your installer for the AHRI reference number of the exact system you are quoted.

      Indoor unitSEER2EER2HSPF2Heat @5°FAHRI ref.
      ZAVA-24HDMB-US · cold climate18.311.710.021,600216980496
      Same unit, other model numbers2

      These model numbers have exactly the same certified ratings and matchups as the ZERO ZSOVA-24HDMB-USHH: the same equipment under another brand, or a variant code for voltage, colour or market. Everything on this page applies to them.

      Yearly running cost in 10 large cities$590-$1,528

      At each state's average electricity price and the city's typical heating and cooling hours.

      Questions6
      What is the SEER2 rating of the ZERO ZSOVA-24HDMB-USHH?
      The ZERO ZSOVA-24HDMB-USHH is rated at up to 18.3 SEER2 and 11.7 EER2 for cooling and up to 10.0 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
      Is the ZERO ZSOVA-24HDMB-USHH good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 21,600 BTU/h at 5°F with a COP of 1.87, so it is still 1.9 times as efficient as electric resistance heat at that temperature.
      How much does the ZERO ZSOVA-24HDMB-USHH cost to run per year?
      At its rated efficiency it costs about $590-$1,528 a year in electricity in large U.S. cities, depending on climate and local rates - for example $720 in Phoenix and $1,271 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
      Is the ZERO ZSOVA-24HDMB-USHH the same as the SLIMAIR SHC24AH224V?
      Yes, as far as the certified ratings go. ENERGY STAR lists 3 model numbers with identical efficiency, capacity and matchups, which means the same outdoor unit sold under a different brand or with a minor variant code (voltage, colour or region). The full list is on this page.
      Which indoor units work with the ZERO ZSOVA-24HDMB-USHH?
      ENERGY STAR lists 1 certified combination for this outdoor unit. The highest-rated one uses ZAVA-24HDMB-US.
      What refrigerant does the ZERO ZSOVA-24HDMB-USHH use?
      It uses R-454B.

      Running cost and savings

      Pre-filled with this model. Pick your city and what you heat with today; everything else is optional.

      Heat pump $711/yrYou save $491/yrSee details ↓
      1. Where you live
      Adjust heating and cooling hours

      Filled in from your city's climate. Change them if you run the system much more or less than usual.

      2. The heat pump ZERO ZSOVA-24HDMB-USHH
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $711
      Current system, per year
      $1,202
      You save per year
      $491
      Payback
      17.3 years
      Net after 10 years
      -$3,589

      Cooling $442Heating $269Electricity used: 4,445 kWhSaved vs. a minimum-efficiency heat pump: $213

      Estimates use the unit's rated SEER2 and HSPF2, full-load hours derived from NOAA 1991-2020 degree days, average residential electricity prices from the U.S. EIA (12 months to July 2026) and fuel prices from EIA (2025 for natural gas, week of 2026-10-05 for propane and heating oil). Very cold days that need backup heat are not modelled. Federal minimum for comparison: 14.3 SEER2 / 7.5 HSPF2.

      Similar 2 ton models

      See all 331 2 ton central heat pumps, ranked

      Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of September 30, 2026. How we use the data.