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Bosch / Climate 5000 A/B legacy R-410A

Bosch Climate 5000 A B Legacy 12k Regular R-410A Mini-Split

Certified capacity
12,000 BTU/h[2]
SEER2
22.3 SEER2[2]
Heating floor
-13 F[1]
Voltage
230 V[1]
Install path
Professional install

This legacy 12k head runs the older R-410A refrigerant on 230V, with a SEER2 of 22.3, EER2 of 13.7, and HSPF2 of 8.8. Its heating is rated 12,000 BTU at 47F, 7,700 BTU at 17F, and 8,400 BTU at 5F - notably rebounding at the coldest point. It is a valid AHRI-certified unit but is not ENERGY STAR certified or cold-climate designated.

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Error Codes
Bosch Climate 5000 A/B legacy R-410A wall-mounted indoor unit (BMS500-AAU012-1AHWXB) for Bosch Climate 5000 A/B legacy R-410A 12,000 BTU Regular (BMS500-AAU012-1AHWXB / BMS500-AAS012-1CSXRA)

Image: Sid Harvey

Data completeness: 92%
Last sourced
Jul 26, 2026

SplitAtlas score

7.9 / 10

Methodology
Cooling efficiencyAbove average

(22.3 SEER2) among 12k systems

Heating efficiencyBottom quartile

(8.8 HSPF2) among 12k systems

Cold-weather performanceBelow average

(70% heat retained at 5F; -13 F heating floor) among 12k systems

NoiseAbove average

(-43 dBA indoor min / 55 dBA outdoor) among 12k systems

WarrantyAbove average

(10 yr parts / 10 yr compressor) across the catalogue

Feature setBottom quartile

(2 verified features) across the catalogue

Documentation & partsBottom quartile

(7 manuals; 18 error-code rows) across the catalogue

Not evaluated

  • Installation accessibility — not applicable (professional install)N/A

    professional install - DIY-accessibility not applicable

  • Price-to-value — not evaluatedN/A

    This is a professionally installed, quote-only system, so we can't score its price. Get an installed quote to compare real cost.

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Key ratings

Rated cooling

12,000BTU/h[2]

Rated heating

12,000BTU/h[2]

Buyer review snapshot

Best for / skip if

Best for

  • High-efficiency shortlists; SEER2 is 22.3.

Skip if

  • You are shopping for a current-generation recommendation; catalog lifecycle is LEGACY.

Install difficulty

Professional install
  • Electrical: 230V; MCA 12 A; breaker/fuse 15 A.
  • Line set: connection type not sourced; precharged 25 ft; max 82 ft.

Alternatives

Availability and price context

We could not verify a current retail price for this model. We could not find a published consumer price for this model when we last checked on 2026-07-26.

Source date

Model data sourced
Jul 26, 2026
Page reviewed
Jul 26, 2026
Source-backed records
4
Newest source retrieved
Jul 26, 2026

Warranty tiers

Warranty: 10 years parts and compressor as standard.

Review methodology

Strengths

  • Heat rebounds to 8,400 BTU at 5F, above its 17F output, which is unusual for a non-cold-climate head.
  • Bosch dealer and warranty support apply as they do across the range.

Weaknesses

  • Built on R-410A, a refrigerant being phased down under tightening restrictions.
  • Not ENERGY STAR certified and not cold-climate rated.

Climate suitability

Minimum heating ambient
-13 F[1]
Rated heating at 5F
8,400 BTU/h[2]
Rated heating at 17F
7,700 BTU/h[2]
Rated heating at 47F
12,000 BTU/h[2]

Specifications

Show
Manufacturer
Bosch
Brand
Bosch
Product line
Climate 5000 A/B legacy R-410A
Model number
BMS500-AAU012-1AHWXB indoor / BMS500-AAS012-1CSXRA outdoor
Indoor unit model
BMS500-AAU012-1AHWXB
Outdoor unit model
BMS500-AAS012-1CSXRA
Number of zones
1
Max indoor units
not published
Rated cooling capacity
12,000 BTU/h[2]
Rated heating capacity
12,000 BTU/h[2]
Voltage
230 V[1]
MCA
12 A[1]
Maximum fuse or breaker size
15 A[1]
Breaker needed
not published
SEER2
22.3 SEER2[2]
EER2
13.7 EER2[2]
HSPF2 (Region 4)
8.8 HSPF2[2]
HSPF2 (Region 5)
not published
COP
not published
COP at 47F
not published
COP at 5F
1.78 COP[2]
Minimum outdoor heating temperature
-13 F[1]
Minimum outdoor cooling temperature
-13 F[1]
Maximum outdoor temperature
122 F[1]
Indoor noise range
24-43 dB(A)[1]
Outdoor noise rating
55 dBA[1]
Indoor weight
19.8 lb[1]
Outdoor weight
76.7 lb[1]
Refrigerant
R-410A[2]
Refrigerant charge
40.6 oz[1]
Manufacturer coverage
not published
Line-set size
1/4 in liquid / 1/2 in suction
Included line-set length
Bosch submittals publish field piping sizes and precharged refrigerant length, but do not specify an included line set for these professional-install systems.
Maximum line-set length
82 ft[1]
Max line set per indoor
not published
Maximum elevation difference
33 ft[1]
Max height between indoor units
not published
Wi-Fi support
not published
Energy Star status
Not ENERGY STAR certified[3]
AHRI certification number
203991149[2]
Warranty
Standard: 10 yr parts / 10 yr compressor (limited residential warranty terms). 10-year compressor / 10-year parts limited residential warranty; terms and field-installed component limits apply.
Install path
Professional install
Retail price
We could not find a published consumer price for this model when we last checked on 2026-07-26.
Available retailers
not published
Manual links
AHRI public directory record 203991149, ENERGY STAR exact check 203991149, Climate 5000 Ductless Mini-Split Heat Pump (R-410A Version) discontinued page, Bosch Climate 5000 ductless mini-split submittal sheet directory, BMS500-AAU012-1AHWXB & BMS500-AAS012-1CSXRA Bosch Climate 5000 A/B legacy R-410A submittal, HVACDirect exact Bosch offer check bosch-climate-5000-r410a-ab-12k-regular-230v, Bosch Home Comfort official Climate 5000 G2/A-B Ductless AC-HP IDU and ODU Service Manuals, wall-mounted error-code tables and diagnosis sections
Specification sheet
not published
Last sourced date
Jul 26, 2026

Electrical requirements

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Voltage
230 V[1]
Voltage range
208/230V[1]
Phase
1[1]
Frequency
60 Hz[1]
MCA
12 A[1]
Breaker needed
not published
Maximum breaker size
15 A[1]
Maximum fuse size
15 A[1]
Maximum cooling current
not published
Maximum heating current
not published
Manufacturer wire notes
not published

Installation considerations

Show
Liquid line
1/4 in[1]
Suction line
1/2 in[1]
Line connection type
not published
Precharged length
25 ft[1]
Included line-set length
Bosch submittals publish field piping sizes and precharged refrigerant length, but do not specify an included line set for these professional-install systems.
Maximum line-set length
82 ft[1]
Max line set per indoor
not published
Max height between indoor units
not published
Indoor dimensions
32.9 x 7.8 x 11.0 in[1]
Outdoor dimensions
31.5 x 13.1 x 21.8 in[1]
Indoor weight
19.8 lb[1]
Outdoor weight
76.7 lb[1]
Drain size
not published

Related systems and guides

Frequently asked questions

Can I install the Bosch Climate 5000 A/B legacy R-410A 12,000 BTU Regular (BMS500-AAU012-1AHWXB / BMS500-AAS012-1CSXRA) myself, or do I need a pro?
Bosch Climate 5000 A/B legacy R-410A 12,000 BTU Regular (BMS500-AAU012-1AHWXB / BMS500-AAS012-1CSXRA) is built for professional installation: the line set must be flared, evacuated, and charged, which requires EPA-certified refrigerant handling. Installing it outside the manufacturer's requirements can void the warranty, so budget for a qualified HVAC installer.
Will the Bosch Climate 5000 A/B legacy R-410A 12,000 BTU Regular (BMS500-AAU012-1AHWXB / BMS500-AAS012-1CSXRA) keep heating in a cold winter?
The manufacturer publishes 8,400 BTU/h of heating output at 5F. Rated heating operation extends down to -13 F. Certified heating efficiency is 8.8 HSPF2. Match those numbers against your climate's design temperature - in cold regions, output at 5F matters far more than the nameplate capacity measured at 47F.
What electrical circuit does the Bosch Climate 5000 A/B legacy R-410A 12,000 BTU Regular (BMS500-AAU012-1AHWXB / BMS500-AAS012-1CSXRA) need?
Published electrical requirements: 230 V voltage, 12 A minimum circuit ampacity, and 15 A maximum breaker or fuse sizing. Confirm the final circuit against the unit nameplate and local code with a licensed electrician.
How far can the outdoor unit be from the indoor head?
The published maximum line-set length is 82 ft, and the included line set comes pre-charged for 25 ft. Longer runs than the included set allows typically mean added refrigerant and a pro visit, so measure the planned routing before ordering.
What warranty does the Bosch Climate 5000 A/B legacy R-410A 12,000 BTU Regular (BMS500-AAU012-1AHWXB / BMS500-AAS012-1CSXRA) carry?
The manufacturer publishes these warranty tiers: Standard: 10 yr parts / 10 yr compressor (limited residential warranty terms). Registration requirements and proof of qualified installation commonly affect coverage, so read the warranty terms before install day.

Data sources

Show
  1. Bosch Thermotechnology Corp.: BMS500-AAU012-1AHWXB & BMS500-AAS012-1CSXRA Bosch Climate 5000 A/B legacy submittalSourced - manufacturer technical document

    Covers Frequency, Maximum breaker size, Maximum fuse size, Minimum circuit ampacity, Phase, Voltage and more

  2. Air-Conditioning, Heating, and Refrigeration Institute: AHRI Appendix M1 public detail for BMS500-AAS012-1CSXRA / BMS500-AAU012-1AHWXBSourced - AHRI directory

    Covers AHRI certification number, performance_spec.cold_climate_designation, Rated cooling capacity, COP at 5F, EER2, Rated heating capacity and more

  3. ENERGY STAR: ENERGY STAR exact row check for AHRI 203991149Sourced - Energy Star listing

    Covers Energy Star status

  4. Bosch Thermotechnology Corp.: Climate 5000 R-454B limited residential warranty statementSourced - manufacturer product page

    Covers Legacy compressor warranty value, Legacy warranty value, Standard compressor warranty, Standard warranty conditions, Standard parts warranty, Warranty notes

Last updated

Jul 26, 2026