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      48,000 BTU mini-split heat pump · BMS Series

      Bosch BMS500-AAS048-1CSXLD

      Below average cooling and heating efficiency for a 48,000 BTU mini-split heat pump, and certified for cold climates.

      Ranks #95 of 146 48,000 BTU mini-splits for cooling efficiency, and costs about $1,332 a year to run in a mixed climate like Atlanta.

      SEER2
      19.0 Cooling efficiency over a season
      Below average · beats 9%
      HSPF2
      9.9 Heating efficiency over a season
      Below average · beats 35%
      EER2
      9.5 Cooling efficiency on a 95°F day
      Below average · beats 3%
      Heat at 5°F
      40,500 BTU/h81% of its 47°F output
      Very good · beats 71%

      A good fit if…

      • Your winters get properly cold - it is ENERGY STAR cold-climate certified, with 40,500 BTU/h at 5°F.
      • You want steady temperatures and quiet running - the compressor varies its speed.

      Think twice if…

      • Cooling cost matters most - its SEER2 is below average for mini-splits.
      • You mainly need heat - its HSPF2 is below average for mini-splits.

      Calculate my running cost

      Details

      Specifications48,000 BTU, R-454B
      General
      BrandBosch
      Also sold asECO-AIR
      Outdoor unit modelBMS500-AAS048-1CSXLD
      SeriesBMS Series
      TypeMini-split heat pump
      Nominal size48,000 BTU
      CompressorVariable-speed units run longer at low powerContinuously variable
      RefrigerantR-454B
      Connected (smart) capableNo
      On the market sinceMarch 18, 2024
      Last certifiedMarch 4, 2025
      Cooling
      SEER2Seasonal efficiency, higher is better19.0 (range 17.1-19.0)
      EER2Efficiency at 95°F outdoors9.5-10.0
      Cooling capacity48,000 BTU/h
      Heating
      HSPF2Seasonal efficiency, higher is better9.8-9.9
      Capacity at 47°F50,000 BTU/h
      Capacity at 17°F36,600-39,000 BTU/h
      Capacity at 5°F38,000-40,500 BTU/h
      COP at 5°F2.0 = twice as efficient as a space heater2.00-2.11
      ENERGY STAR cold climateYes
      Heating output as it gets colder81% kept at 5°F

      Every heat pump delivers less heat as the outdoor temperature drops. Certified output of its matchup with BMS500-AAU048-1AHCXD at the standard test temperatures, in BTU/h:

      Certified matchups2 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-AAU048-1AHCXD BOSCH · cold climate19.09.59.940,500215223313
      BMS500-AAU048-1AHDXD BOSCH · cold climate17.110.09.838,000215223314
      Same unit, other model numbers1

      These model numbers have exactly the same certified ratings and matchups as the Bosch BMS500-AAS048-1CSXLD: the same equipment under another brand, or a variant code for voltage, colour or market. Everything on this page applies to them.

      Yearly running cost in 10 large cities$1,187-$3,187

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

      Questions6
      What is the SEER2 rating of the Bosch BMS500-AAS048-1CSXLD?
      The Bosch BMS500-AAS048-1CSXLD is rated at up to 19.0 SEER2 and 9.5 EER2 for cooling and up to 9.9 HSPF2 for heating. The exact figure depends on the indoor unit it is paired with; across its 2 certified matchups SEER2 ranges from 17.1-19.0.
      Is the Bosch BMS500-AAS048-1CSXLD good for cold climates?
      Yes. At least one certified matchup meets the ENERGY STAR cold-climate criteria, delivering up to 40,500 BTU/h at 5°F with a COP of 2.11, so it is still 2.1 times as efficient as electric resistance heat at that temperature.
      How much does the Bosch BMS500-AAS048-1CSXLD cost to run per year?
      At its rated efficiency it costs about $1,187-$3,187 a year in electricity in large U.S. cities, depending on climate and local rates - for example $1,465 in Phoenix and $2,664 in Minneapolis. The calculator on this page works it out for your city and compares it with your current system.
      Is the Bosch BMS500-AAS048-1CSXLD the same as the ECO-AIR EDSO-48E?
      Yes, as far as the certified ratings go. ENERGY STAR lists both model numbers with identical efficiency, capacity and matchups, which means the same outdoor unit sold under a different brand or with a minor variant code (voltage, colour or region). The full list is on this page.
      Which indoor units work with the Bosch BMS500-AAS048-1CSXLD?
      ENERGY STAR lists 2 certified combinations for this outdoor unit. The highest-rated ones use BOSCH BMS500-AAU048-1AHCXD, BOSCH BMS500-AAU048-1AHDXD.
      What refrigerant does the Bosch BMS500-AAS048-1CSXLD 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 $1,455/yrYou save $1,053/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-AAS048-1CSXLD
      3. What it replaces
      4. Price replace the example with your quote
      Heat pump, per year
      $1,455
      Current system, per year
      $2,508
      You save per year
      $1,053
      Payback
      17.1 years
      Net after 10 years
      -$7,472

      Cooling $889Heating $566Electricity used: 9,093 kWhSaved vs. a minimum-efficiency heat pump: $473

      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 146 48,000 BTU mini-splits, ranked

      Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), certification of March 4, 2025. How we use the data.