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      3.5-ton central heat pump · DRU Series

      DuraSTAR DRU1H42S2A

      Average cooling efficiency and very good heating efficiency for a 3.5-ton central heat pump, and certified for cold climates.

      Ranks #41 of 138 3.5 ton central heat pumps for cooling efficiency, and costs about $1,331 a year to run in a mixed climate like Atlanta.

      SEER2
      16.7 Cooling efficiency over a season
      Average · beats 43%
      HSPF2
      9.5 Heating efficiency over a season
      Very good · beats 70%
      EER2
      11.7 Cooling efficiency on a 95°F day
      Average · beats 43%
      Heat at 5°F
      46,000 BTU/h92% of its 47°F output
      Below average · beats 20%

      A good fit if…

      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 46,000 BTU/h at 5°F.
      • It will heat most of the year - its HSPF2 beats 70% of central heat pumps.
      • You want steady temperatures and quiet running - the compressor varies its speed.
      • You want a choice of indoor units - 28 certified pairings.

      Think twice if…

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

      Calculate my running cost

      Details

      Specifications3.5 ton, R-454B
      General
      BrandDuraSTAR
      Outdoor unit modelDRU1H42S2A
      SeriesDRU Series
      TypeCentral heat pump
      Nominal size3.5 ton
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-454B
      Connected (smart) capableNo
      On the market sinceDecember 8, 2020
      Last certifiedMay 1, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better16.7 (range 15.2-16.7)
      EER2Efficiency at 95°F outdoors9.8-11.7
      Cooling capacity42,000-48,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better8.1-9.5
      Capacity at 47°F46,000-50,000 BTU/h
      Capacity at 17°F30,000-39,500 BTU/h
      Capacity at 5°F41,000-46,000 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater1.75-1.90
      ENERGY STAR cold climateYes
      Heating output as it gets colder92% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with DRUM4260S2A at the standard test temperatures, in BTU/h:

      Certified matchups28 indoor units

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

      Indoor unitFurnaceSEER2EER2HSPF2Heat @5°FAHRI ref.
      DRUM4260S2A · cold climate-16.711.79.546,000215374888
      DRUC6021S2A · cold climateS9V2C100U5VS***16.610.08.642,000218071908
      DRUC6021S2A · cold climateS9V2C100D5VS***16.610.08.642,000218071907
      DRUC6021S2A · cold climateS9V2B080U4VS***16.610.08.541,000218071719
      DRUC6021S2A · cold climateS9V2C080U5VS***16.510.08.542,000218071906
      DRUC6021S2A · cold climateML296UH110XV60C*16.510.58.241,000218072333
      DRUC6021S2A · cold climateS9X2C080U5PSB**16.410.28.341,000218071986
      DRUC6021S2A · cold climateS9X1C080U5PSB**16.410.28.341,000218071909
      DRUC6021S2A · cold climateML193UH110XE48B*16.310.68.141,000218072326
      DRUC6021S2A · cold climateML193UH110XE48C*16.310.68.141,000218072412
      DRUC6024S2A · cold climateS9V2D120U5VS***16.19.88.541,000218071913
      DRUC6024S2A · cold climateS9V2D120D5VS***16.19.88.541,000218071912
      DRUC6021S2A · cold climateML193UH090XE48B*16.110.28.242,000218072325
      DRUC6021S2A · cold climateRL18100C20MPS116.110.58.242,000218072100
      DRUC6021S2A · cold climateRL18100C16MPS116.110.58.242,000218072099
      DRUC6021S2A · cold climateML193UH090XE48C*16.110.28.242,000218072409
      DRUC6021S2A · cold climateML296UH090XV48B*16.010.48.141,000218072332
      DRUC6021S2A · cold climateML296UH090XV48C*16.010.48.141,000218072419
      DRUC6021S2A · cold climateML296DF090XV60C*15.910.38.141,000218072331
      DRUC6021S2A · cold climateRG19100C20MPS115.810.28.342,000218072049
      DRUC6021S2A · cold climateML196UH090XE60C*15.510.38.342,000218072329
      DRUC6021S2A · cold climateMGV96U100C5C15.510.48.341,000218071747
      DRUC6021S2A · cold climateML193UH110XE60C*15.410.58.442,000218072327
      DRUC6024S2A · cold climateRL18130D20MPS115.49.98.242,000218072101
      DRUC6021S2A · cold climateRG19100C16MPS115.410.38.242,000218072048
      DRUC6021S2A · cold climateML196DF110XE60C*15.310.68.442,000218072328
      DRUC6021S2A · cold climateML196UH110XE60C*15.310.58.341,000218072330
      DRUC6021S2A · cold climateMGV96U080C4C15.210.58.542,000218071746
      Yearly running cost in 10 large cities$1,262-$3,121

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

      Questions5
      What is the SEER2 rating of the DuraSTAR DRU1H42S2A?
      The DuraSTAR DRU1H42S2A is rated at up to 16.7 SEER2 and 11.7 EER2 for cooling and up to 9.5 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 28 certified matchups SEER2 ranges from 15.2-16.7.
      Is the DuraSTAR DRU1H42S2A good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 46,000 BTU/h at 5°F with a COP of 1.90, so it is still 1.9 times as efficient as electric resistance heat at that temperature.
      How much does the DuraSTAR DRU1H42S2A cost to run per year?
      At its rated efficiency it costs about $1,262-$3,121 a year in electricity in large U.S. cities, depending on climate and local rates - for example $1,521 in Phoenix and $2,581 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
      Which indoor units work with the DuraSTAR DRU1H42S2A?
      ENERGY STAR lists 28 certified combinations for this outdoor unit. The highest-rated ones use DRUM4260S2A, DRUC6021S2A, DRUC6024S2A.
      What refrigerant does the DuraSTAR DRU1H42S2A 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 $1,491/yrYou save $846/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 DuraSTAR DRU1H42S2A
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $1,491
      Current system, per year
      $2,337
      You save per year
      $846
      Payback
      20.1 years
      Net after 10 years
      -$8,541

      Cooling $949Heating $542Electricity used: 9,318 kWhSaved vs. a minimum-efficiency heat pump: $304

      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 3.5 ton models

      See all 138 3.5 ton central heat pumps, ranked

      Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of May 1, 2026. How we use the data.