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      2.5-ton central heat pump · 15 SEER2 HP

      Grandaire W5H5S31*K*AAA

      Below average cooling and heating efficiency for a 2.5-ton central heat pump, but not rated for cold climates.

      Ranks #156 of 199 2.5 ton central heat pumps for cooling efficiency, and costs about $956 a year to run in a mixed climate like Atlanta.

      SEER2
      16.0 Cooling efficiency over a season
      Below average · beats 26%
      HSPF2
      8.0 Heating efficiency over a season
      Below average · beats 12%
      EER2
      13.0 Cooling efficiency on a 95°F day
      Very good · beats 89%
      Heat at 5°F
      14,000 BTU/h45% of its 47°F output
      Average · beats 51%

      A good fit if…

      • You want a choice of indoor units - 30 certified pairings.

      Think twice if…

      • You often see nights below 0°F - it is not cold-climate certified.
      • 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.
      • Comfort and noise matter - a single-stage compressor runs only full-on or off.

      Calculate my running cost

      Details

      Specifications2.5 ton, R-454B
      General
      BrandGrandaire
      Also sold asECOTEMP
      Outdoor unit modelW5H5S31*K*AAA
      Series15 SEER2 HP
      TypeCentral heat pump
      Nominal size2.5 ton
      CompressorVariable-speed units run longer at low powerSingle stage
      RefrigerantR-454B
      Connected (smart) capableNo
      On the market sinceJuly 31, 2025
      Last certifiedJune 29, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better16.0 (range 15.2-16.0)
      EER2Efficiency at 95°F outdoors12.0-13.0
      Cooling capacity27,400-29,400 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better7.8-8.0
      Capacity at 47°F29,400-30,600 BTU/h
      Capacity at 17°F17,500-18,100 BTU/h
      Capacity at 5°F13,400-14,000 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.00-2.06
      ENERGY STAR cold climateNo
      Heating output as it gets colder45% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with WCHL425*C at the standard test temperatures, in BTU/h:

      Certified matchups30 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.
      WCHL425*C-16.013.08.013,400217683397
      WCHL425*C-16.013.08.013,400217683398
      FM(C,U)5Z36**AL-16.012.58.013,400217683525
      FM(C,U)5Z36**AL-16.012.58.013,400217683526
      FM(C,U)5Z30**AL-16.012.58.013,400217683493
      FM(C,U)5Z30**AL-16.012.58.013,400217683494
      FMA5X30**AL-16.013.08.013,700217683621
      FMA5X30**AL-16.013.08.013,700217683622
      FMA5X36**AL-16.013.08.013,700217683653
      FMA5X36**AL-16.013.08.013,700217683654
      W5A*43M21XAWFEU080C060B*15.512.58.014,000217692248
      W5A*43M21XAWFEU080C060B*15.512.58.014,000217692249
      W5A*43M21XAWFAX100C060B*15.512.58.014,000217692765
      W5A*43M21XAWFAX100C060B*15.512.58.014,000217692766
      W5A*43M21XAWFE*110C060C*15.512.58.014,000217692087
      W5A*43M21XAWFE*110C060C*15.512.58.014,000217692088
      W5A*43M21XAWFEU060B048B*15.512.08.014,000217692221
      W5A*43M21XAWFEU060B048B*15.512.08.014,000217692222
      FM(C,U)5S36**AL-15.512.58.013,500218452507
      FM(C,U)5S36**AL-15.512.58.013,500218452506
      FM(C,U)5S30**AL-15.512.58.013,500218452488
      FM(C,U)5S30**AL-15.512.58.013,500218452487
      WCHL305*B-15.512.57.813,400217683269
      WCHL305*B-15.512.57.813,400217683270
      FEVA0036**+NAVA53601CK-15.512.57.813,400217702182
      FEVA0036**+NAVA53601CK-15.512.57.813,400217702183
      FEVB0036**+NAVA53601CK-15.512.57.813,400217702209
      FEVB0036**+NAVA53601CK-15.512.57.813,400217702210
      FMA5L30**AL-15.212.08.013,800217683557
      FMA5L30**AL-15.212.08.013,800217683558
      Yearly running cost in 10 large cities$824-$2,311

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

      Questions5
      What is the SEER2 rating of the Grandaire W5H5S31*K*AAA?
      The Grandaire W5H5S31*K*AAA is rated at up to 16.0 SEER2 and 13.0 EER2 for cooling and up to 8.0 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 30 certified matchups SEER2 ranges from 15.2-16.0.
      Is the Grandaire W5H5S31*K*AAA good for cold climates?
      It is not cold-climate certified: none of its matchups meet the ENERGY STAR cold-climate criteria (a COP of at least 1.75 at 5°F among other limits). In places with frequent sub-zero nights, pick a cold-climate 2.5-ton model.
      How much does the Grandaire W5H5S31*K*AAA cost to run per year?
      At its rated efficiency it costs about $824-$2,311 a year in electricity in large U.S. cities, depending on climate and local rates - for example $1,031 in Phoenix and $1,942 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 Grandaire W5H5S31*K*AAA?
      ENERGY STAR lists 30 certified combinations for this outdoor unit. The highest-rated ones use WCHL425*C, FM(C,U)5Z36**AL, FM(C,U)5Z30**AL.
      What refrigerant does the Grandaire W5H5S31*K*AAA 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 $1,030/yrYou save $440/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 Grandaire W5H5S31*K*AAA
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $1,030
      Current system, per year
      $1,470
      You save per year
      $440
      Payback
      23.9 years
      Net after 10 years
      -$6,105

      Cooling $616Heating $414Electricity used: 6,440 kWhSaved vs. a minimum-efficiency heat pump: $101

      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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      See all 199 2.5 ton central heat pumps, ranked

      Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of June 29, 2026. How we use the data.