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      3.5-ton central heat pump · W Series

      Rheem WP15AZ42AJ2N

      Below average cooling and heating efficiency for a 3.5-ton central heat pump, and certified for cold climates.

      Ranks #122 of 138 3.5 ton central heat pumps for cooling efficiency, and costs about $1,324 a year to run in a mixed climate like Atlanta.

      SEER2
      15.2 Cooling efficiency over a season
      Below average · beats 6%
      HSPF2
      8.1 Heating efficiency over a season
      Below average · beats 20%
      EER2
      11.7 Cooling efficiency on a 95°F day
      Average · beats 43%
      Heat at 5°F
      20,400 BTU/h52% of its 47°F output
      Average · beats 58%

      A good fit if…

      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 20,400 BTU/h at 5°F.
      • You want a choice of indoor units - 10 certified pairings.

      Think twice if…

      • Cooling cost matters most - its SEER2 is below average for central heat pumps.
      • You mainly need heat - its HSPF2 is below average for central heat pumps.
      • You want the newest refrigerant - it uses R-410A, which is being phased down.

      Calculate my running cost

      Details

      Specifications3.5 ton, R-410A
      General
      BrandRheem
      Also sold asRuud, WeatherKing, Fujitsu
      Outdoor unit modelWP15AZ42AJ2N
      SeriesW Series
      TypeCentral heat pump
      Nominal size3.5 ton
      CompressorVariable-speed units run longer at low powerTwo-stage
      RefrigerantR-410A
      Connected (smart) capableNo
      On the market sinceMarch 2, 2023
      Last certifiedJune 3, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better15.2 (range 15.2)
      EER2Efficiency at 95°F outdoors11.7
      Cooling capacity40,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better8.1
      Capacity at 47°F39,500 BTU/h
      Capacity at 17°F26,000 BTU/h
      Capacity at 5°F20,400 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.10
      ENERGY STAR cold climateYes
      Heating output as it gets colder52% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with FHRNTT4821S*ZTNA at the standard test temperatures, in BTU/h:

      Certified matchups10 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.
      FHRNTT4821S*ZTNA · cold climate15.211.78.120,400211641688
      RH2TZ4821STANN · cold climate15.211.78.120,400211627524
      RH2TZ4821STANN · cold climate15.211.78.120,400211627525
      WH2TZ4821STANN · cold climate15.211.78.120,400211627526
      WH2TZ4821STANN · cold climate15.211.78.120,400213318042
      WH2TZ4821STANN · cold climate15.211.78.120,400213318052
      WH3VZ4821STANN15.211.78.120,400214779287
      WH3VZ4821STANN15.211.78.120,400214779514
      RH3VZ4821STACN15.211.78.120,400214664614
      RH3VZ4821STACN15.211.78.120,400214664611
      Yearly running cost in 10 large cities$1,234-$3,124

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

      Questions5
      What is the SEER2 rating of the Rheem WP15AZ42AJ2N?
      The Rheem WP15AZ42AJ2N is rated at up to 15.2 SEER2 and 11.7 EER2 for cooling and up to 8.1 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with.
      Is the Rheem WP15AZ42AJ2N good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 20,400 BTU/h at 5°F with a COP of 2.10, so it is still 2.1 times as efficient as electric resistance heat at that temperature.
      How much does the Rheem WP15AZ42AJ2N cost to run per year?
      At its rated efficiency it costs about $1,234-$3,124 a year in electricity in large U.S. cities, depending on climate and local rates - for example $1,497 in Phoenix and $2,591 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 Rheem WP15AZ42AJ2N?
      ENERGY STAR lists 10 certified combinations for this outdoor unit. The highest-rated ones use FHRNTT4821S*ZTNA, RH2TZ4821STANN, WH2TZ4821STANN.
      What refrigerant does the Rheem WP15AZ42AJ2N use?
      It uses R-410A. R-410A is being phased down under the EPA AIM Act, and new systems are moving to R-454B and R-32.

      Running cost and savings

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

      Heat pump $1,472/yrYou save $582/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 Rheem WP15AZ42AJ2N
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $1,472
      Current system, per year
      $2,054
      You save per year
      $582
      Payback
      25.8 years
      Net after 10 years
      -$9,182

      Cooling $926Heating $546Electricity used: 9,203 kWhSaved vs. a minimum-efficiency heat pump: $102

      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.

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      Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of June 3, 2026. How we use the data.