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      12,000 BTU mini-split heat pump · BMS500

      Bosch BMS500-AAS012-1CSXRC

      Very good cooling efficiency and average heating efficiency for a 12,000 BTU mini-split heat pump, and certified for cold climates.

      Ranks #140 of 394 12,000 BTU mini-splits for cooling efficiency, and costs about $281 a year to run in a mixed climate like Atlanta.

      SEER2
      24.6 Cooling efficiency over a season
      Very good · beats 80%
      HSPF2
      10.7 Heating efficiency over a season
      Average · beats 68%
      EER2
      13.7 Cooling efficiency on a 95°F day
      Very good · beats 78%
      Heat at 5°F
      8,400 BTU/h67% of its 47°F output
      Excellent · beats 91%

      A good fit if…

      • You want low cooling bills - its SEER2 beats 80% of mini-splits.
      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 8,400 BTU/h at 5°F.
      • You want steady temperatures and quiet running - the compressor varies its speed.

      Think twice if…

      • You want the newest refrigerant - it uses R-410A, which is being phased down.

      Calculate my running cost

      Details

      Specifications12,000 BTU, R-410A
      General
      BrandBosch
      Outdoor unit modelBMS500-AAS012-1CSXRC
      SeriesBMS500
      TypeMini-split heat pump
      Nominal size12,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-410A
      Connected (smart) capableNo
      On the market sinceJanuary 1, 2022
      Last certifiedApril 27, 2026
      Cooling
      SEER2Seasonal efficiency, higher is better24.6 (range 19.0-24.6)
      EER2Efficiency at 95°F outdoors11.7-14.0
      Cooling capacity11,500-12,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better10.0-10.7
      Capacity at 47°F12,000 BTU/h
      Capacity at 17°F8,900-9,300 BTU/h
      Capacity at 5°F8,000-8,400 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.26-2.39
      ENERGY STAR cold climateYes
      Heating output as it gets colder67% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with BMS500-AAU012-1AHWXC at the standard test temperatures, in BTU/h:

      Certified matchups3 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.
      BMS500-AAU012-1AHWXC BOSCH24.613.710.78,000207759990
      BMS500-AAU012-1AHCXB BOSCH22.714.010.08,000207760045
      BMS500-AAU012-1AHDXB BOSCH · cold climate19.011.710.38,400207760002
      Yearly running cost in 10 large cities$230-$690

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

      Questions5
      What is the SEER2 rating of the Bosch BMS500-AAS012-1CSXRC?
      The Bosch BMS500-AAS012-1CSXRC is rated at up to 24.6 SEER2 and 13.7 EER2 for cooling and up to 10.7 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 3 certified matchups SEER2 ranges from 19.0-24.6.
      Is the Bosch BMS500-AAS012-1CSXRC good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 8,400 BTU/h at 5°F with a COP of 2.39, so it is still 2.4 times as efficient as electric resistance heat at that temperature.
      How much does the Bosch BMS500-AAS012-1CSXRC cost to run per year?
      At its rated efficiency it costs about $230-$690 a year in electricity in large U.S. cities, depending on climate and local rates - for example $294 in Phoenix and $584 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 Bosch BMS500-AAS012-1CSXRC?
      ENERGY STAR lists 3 certified combinations for this outdoor unit. The highest-rated ones use BOSCH BMS500-AAU012-1AHWXC, BOSCH BMS500-AAU012-1AHCXB, BOSCH BMS500-AAU012-1AHDXB.
      What refrigerant does the Bosch BMS500-AAS012-1CSXRC 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 $297/yrYou save $321/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 Bosch BMS500-AAS012-1CSXRC
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $297
      Current system, per year
      $619
      You save per year
      $321
      Payback
      14.0 years
      Net after 10 years
      -$1,286

      Cooling $172Heating $126Electricity used: 1,858 kWhSaved vs. a minimum-efficiency heat pump: $177

      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 April 27, 2026. How we use the data.