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      2.5-ton central heat pump · MAINLINE 16 SEER2 HP

      Heil B5H6S31*K*AAA

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

      Ranks #157 of 199 2.5 ton central heat pumps for cooling efficiency, and costs about $992 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/h46% of its 47°F output
      Average · beats 51%

      A good fit if…

      • You want a choice of indoor units - 304 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
      BrandHeil
      Also sold asKenmore, Arcoaire, Airquest, Keeprite, Day & Night, Comfortmaker, Tempstar
      Outdoor unit modelB5H6S31*K*AAA
      SeriesMAINLINE 16 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 certifiedJuly 16, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better16.0 (range 15.2-16.0)
      EER2Efficiency at 95°F outdoors11.7-13.0
      Cooling capacity27,400-29,400 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better7.8-8.0
      Capacity at 47°F29,200-30,600 BTU/h
      Capacity at 17°F17,300-18,200 BTU/h
      Capacity at 5°F13,100-14,000 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 colder46% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with FMA5X36**AL at the standard test temperatures, in BTU/h:

      Certified matchups304 indoor units

      The same outdoor unit scores differently with each indoor unit and furnace. The 60 highest-rated of 304 are shown. Ask your installer for the AHRI reference number of the exact system you are quoted.

      Indoor unitFurnaceSEER2EER2HSPF2Heat @5°FAHRI ref.
      FMA5X36**AL-16.013.08.013,700218188634
      FMA5X30**AL-16.013.08.013,700218188633
      FM(C,U)5Z36**AL-16.012.58.013,400218188630
      FM(C,U)5Z30**AL-16.012.58.013,400218188629
      FHMA5*42L*C-16.013.08.013,400218188626
      F5MA5*42L*C-16.013.08.013,400218190802
      FMA5X36**AL-16.013.08.013,700218197701
      FMA5X30**AL-16.013.08.013,700218197700
      FM(C,U)5Z36**AL-16.012.58.013,400218197697
      FM(C,U)5Z30**AL-16.012.58.013,400218197696
      F5MA5*42L*C-16.013.08.013,400218197693
      FHMA5*42L*C-16.013.08.013,400218197692
      FMA5X36**AL-16.013.08.013,700218205335
      FMA5X30**AL-16.013.08.013,700218205331
      FM(C,U)5Z36**AL-16.012.58.013,400218205325
      FM(C,U)5Z30**AL-16.012.58.013,400218205321
      F5MA5*42L*C-16.013.08.013,400218205312
      FHMA5*42L*C-16.013.08.013,400218205308
      FMA5X36**AL-16.013.08.013,700218206436
      FMA5X36**AL-16.013.08.013,700218206435
      FMA5X36**AL-16.013.08.013,700218206434
      FMA5X30**AL-16.013.08.013,700218206433
      FMA5X30**AL-16.013.08.013,700218206432
      FMA5X30**AL-16.013.08.013,700218206431
      FM(C,U)5Z36**AL-16.012.58.013,400218206424
      FM(C,U)5Z36**AL-16.012.58.013,400218206423
      FM(C,U)5Z36**AL-16.012.58.013,400218206422
      FM(C,U)5Z30**AL-16.012.58.013,400218206421
      FM(C,U)5Z30**AL-16.012.58.013,400218206420
      FM(C,U)5Z30**AL-16.012.58.013,400218206419
      F5MA5*42L*C-16.013.08.013,400218206412
      FHMA5*42L*C-16.013.08.013,400218206411
      F5MA5*42L*C-16.013.08.013,400218206410
      FHMA5*42L*C-16.013.08.013,400218206409
      F5MA5*42L*C-16.013.08.013,400218206408
      FHMA5*42L*C-16.013.08.013,400218206407
      FMA5X36**AL-16.013.08.013,700218210719
      FMA5X36**AL-16.013.08.013,700218210718
      FMA5X30**AL-16.013.08.013,700218210717
      FMA5X30**AL-16.013.08.013,700218210716
      FM(C,U)5Z36**AL-16.012.58.013,400218210711
      FM(C,U)5Z36**AL-16.012.58.013,400218210710
      FM(C,U)5Z30**AL-16.012.58.013,400218210709
      FM(C,U)5Z30**AL-16.012.58.013,400218210708
      F5MA5*42L*C-16.013.08.013,400218210703
      FHMA5*42L*C-16.013.08.013,400218210702
      F5MA5*42L*C-16.013.08.013,400218210701
      FHMA5*42L*C-16.013.08.013,400218210700
      EA*5X37M21A*92MSN1002122A*15.512.58.014,000218188997
      EA*5X37M21A*92MSN1002120A*15.512.58.014,000218188996
      EA*5X37M21A*92MSN0802120A*15.512.58.014,000218188995
      EA*5X37M21A*80MSU0802120A*15.512.58.014,000218188974
      EA*5X37M21A*80MSU0601716A*15.512.08.014,000218188973
      EA*5X37M21A*80VSL1102122B*15.512.58.014,000218188971
      EA*5X37M21A*80MS(N,L)1102120A*15.512.58.014,000218188967
      EA*5X37M21A*80MS(N,L)0902120A*15.512.58.014,000218188966
      EA*5X37M21A*+WALLCON*80CSU0802120B*15.512.58.014,000218188959
      EA*5X37M21A*+WALLCON*80CSU0401712B*15.512.08.013,900218188957
      EA*5X43M21A*97VTN1002122A*15.513.08.014,000218190429
      EA*5X43M21A*96VTN1002122B*15.513.08.014,000218190424
      Yearly running cost in 10 large cities$859-$2,393

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

      Questions5
      What is the SEER2 rating of the Heil B5H6S31*K*AAA?
      The Heil B5H6S31*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 304 certified matchups SEER2 ranges from 15.2-16.0.
      Is the Heil B5H6S31*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 Heil B5H6S31*K*AAA cost to run per year?
      At its rated efficiency it costs about $859-$2,393 a year in electricity in large U.S. cities, depending on climate and local rates - for example $1,072 in Phoenix and $2,009 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 Heil B5H6S31*K*AAA?
      ENERGY STAR lists 304 certified combinations for this outdoor unit. The highest-rated ones use FMA5X36**AL, FMA5X30**AL, FM(C,U)5Z36**AL.
      What refrigerant does the Heil B5H6S31*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 $1,071/yrYou save $458/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 Heil B5H6S31*K*AAA
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $1,071
      Current system, per year
      $1,529
      You save per year
      $458
      Payback
      24.0 years
      Net after 10 years
      -$6,423

      Cooling $642Heating $428Electricity used: 6,693 kWhSaved vs. a minimum-efficiency heat pump: $105

      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 2.5 ton models

      See all 199 2.5 ton central heat pumps, ranked

      Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of July 16, 2026. How we use the data.