Panasonic / Project Series High Wall
Panasonic Project High Wall 12k R-454B 208/230V Mini-Split
The Project Series 12k is Panasonic's builder-oriented line: SEER2 23.1 with a -13F heating floor, on current R-454B. It sits slightly below the ClimaPure XZ and EXTERIOS Z lines on efficiency (they reach 27.5) but holds a colder rating than their -15F suggests at this size, and it is aimed at multi-unit and new-construction work where consistency across a project matters more than the top number.
1 zoneProfessional installCurrent
Refrigerant generation
R-454B - current-generation refrigerant
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Image: Panasonic
Data completeness: 92%
- Last sourced
- Jul 23, 2026
SplitAtlas score
9.0 / 10
Cooling efficiencyAbove average
(23.1 SEER2) among 12k systems
Heating efficiencyTop 10%
(11.5 HSPF2) among 12k systems
Cold-weather performanceBelow average
(71.7% heat retained at 5F; -13 F heating floor) among 12k systems
NoiseAbove average
(-43 dBA indoor min / 54 dBA outdoor) among 12k systems
Feature setTop 10%
(7 verified features) across the catalogue
Documentation & partsBelow average
(10 manuals; spec sheet) 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
Buyer review snapshot
Best for / skip if
Best for
- High-efficiency shortlists; SEER2 is 23.1.
Install difficulty
Professional install
- Electrical: 230V; MCA 12 A; breaker/fuse 15 A.
- Line set: connection type not sourced; max 82 ft.
Availability and price context
We could not verify a current retail price for this model. We could not find this exact model in stock at a retailer we work with when we last checked on 2026-07-23.
Source date
- Model data sourced
- Jul 23, 2026
- Page reviewed
- Jul 23, 2026
- Source-backed records
- 4
- Newest source retrieved
- Jul 23, 2026
Strengths
- SEER2 23.1 with -13F rated heating on current R-454B.
- Built for project consistency across multiple units.
Weaknesses
- ClimaPure XZ and EXTERIOS Z certify higher, reaching SEER2 27.5.
- Panasonic has no line rated below -15F, so deep cold is not its strength.
Climate suitability
- Minimum heating ambient
- -13 F[1]
- Rated heating at 5F
- 8,600 BTU/h[3]
- Rated heating at 17F
- 10,400 BTU/h[3]
- Rated heating at 47F
- 12,000 BTU/h[3]
Specifications
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- Manufacturer
- Panasonic
- Brand
- Panasonic
- Product line
- Project Series High Wall
- Model number
- CS-YM12CKUW indoor / CU-YM12CBUC outdoor
- Indoor unit model
- CS-YM12CKUW
- Outdoor unit model
- CU-YM12CBUC
- Number of zones
- 1
- Max indoor units
- not published
- Rated cooling capacity
- 12,000 BTU/h[3]
- Rated heating capacity
- 12,000 BTU/h[3]
- Voltage
- 230 V[1]
- MCA
- 12 A[1]
- Maximum fuse or breaker size
- 15 A[1]
- Breaker needed
- not published
- SEER2
- 23.1 SEER2[3]
- EER2
- 12.2 EER2[3]
- HSPF2 (Region 4)
- 11.5 HSPF2[3]
- HSPF2 (Region 5)
- not published
- COP
- not published
- COP at 47F
- 3.69 COP[1]
- COP at 5F
- 2.35 COP[3]
- Minimum outdoor heating temperature
- -13 F[1]
- Minimum outdoor cooling temperature
- -13 F[1]
- Maximum outdoor temperature
- 122 F[1]
- Indoor noise range
- 20.0-43.0 dB(A)[1]
- Outdoor noise rating
- 54 dBA[1]
- Indoor weight
- 18.96 lb[1]
- Outdoor weight
- 62.17 lb[1]
- Refrigerant
- R-454B[1]
- Refrigerant charge
- 32.45 oz[1]
- Manufacturer coverage
- not published
- Line-set size
- 1/4 in liquid / 3/8 in suction
- Included line-set length
- Panasonic Project Series High Wall professional-install sources publish refrigerant piping size, maximum length, and height difference, but no included line set.
- Maximum line-set length
- 82 ft[1]
- Max line set per indoor
- not published
- Maximum elevation difference
- 49.2 ft[1]
- Max height between indoor units
- not published
- Wi-Fi support
- not supported[2]
- Energy Star status
- ENERGY STAR certified[4]
- AHRI certification number
- 218027961[3]
- Warranty
- not published
- Install path
- Professional install
- Retail price
- We could not find this exact model in stock at a retailer we work with when we last checked on 2026-07-23.
- Available retailers
- not published
- Manual links
- AHRI certificate 218027961, AHRI public directory record 218027961, ENERGY STAR record 4520552 for CU-YM12CBUC / CS-YM12CKUW, HVACDirect exact Panasonic Project Series High Wall model search summary, Panasonic Project Series High Wall 12,000 BTU submittal extracted text, Panasonic Project Series catalog extracted text, Panasonic Project Series High Wall manufacturer page snapshot, Panasonic Project Series High Wall source manifest, Panasonic Project Series Heat Pump Solutions catalog, Panasonic Project Series High Wall 12,000 BTU submittal
- Specification sheet
- Panasonic Project Series Heat Pump Solutions catalog
- Last sourced date
- Jul 23, 2026
Installation considerations
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- Liquid line
- 1/4 in[1]
- Suction line
- 3/8 in[1]
- Line connection type
- not published
- Precharged length
- not published
- Included line-set length
- Panasonic Project Series High Wall professional-install sources publish refrigerant piping size, maximum length, and height difference, but no included line set.
- Maximum line-set length
- 82 ft[1]
- Max line set per indoor
- not published
- Max height between indoor units
- not published
- Indoor dimensions
- 31-9/16 x 7-7/8 x 11-5/8 in[1]
- Outdoor dimensions
- 30-1/8 x 11-15/16 x 21-7/8 in[1]
- Indoor weight
- 18.96 lb[1]
- Outdoor weight
- 62.17 lb[1]
- Drain size
- not published
Related systems and guides
- More Panasonic systems
- DIY 5th Gen Hyper Heat 12k
- Perfect Aire Quick Connect 12k 115V
- EXTERIOS Z Series 11.5k
- Panasonic ClimaPure XZ Series 14.7k 230V
- Guide library
- Mini split buying guide
- Single-zone vs multi-zone mini splits
- Troubleshooting
- Do mini splits work in cold weather?
- The best 12,000 BTU mini splits of 2026
- The best cold-climate mini splits of 2026
- The best mini splits for heating of 2026
- Mini split heating capacity in the cold: what your unit actually delivers at 5F
- The mini split defrost cycle, explained
- The best DIY mini splits of 2026
- What "DIY mini split" actually means
- How to install a mini split (DIY overview)
- R-32 vs R-454B: the mini split refrigerant change explained
- Mini split not heating
- Mini split indoor unit freezing up
- Mini split remote not working
- Mini split Wi-Fi not connecting
- Your mini split is showing a refrigerant leak code
- Line sets
- Line-set covers
Frequently asked questions
- Can I install the Panasonic Project Series High Wall 12,000 BTU R-454B 208/230V (CS-YM12CKUW / CU-YM12CBUC) myself, or do I need a pro?
- Panasonic Project Series High Wall 12,000 BTU R-454B 208/230V (CS-YM12CKUW / CU-YM12CBUC) 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 Panasonic Project Series High Wall 12,000 BTU R-454B 208/230V (CS-YM12CKUW / CU-YM12CBUC) keep heating in a cold winter?
- The manufacturer publishes 8,600 BTU/h of heating output at 5F. Rated heating operation extends down to -13 F. Certified heating efficiency is 11.5 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 Panasonic Project Series High Wall 12,000 BTU R-454B 208/230V (CS-YM12CKUW / CU-YM12CBUC) 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. Longer runs than the included set allows typically mean added refrigerant and a pro visit, so measure the planned routing before ordering.
Data sources
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- Panasonic Corporation of North America: Panasonic Project Series Heat Pump Solutions catalog high-wall specificationsSourced - manufacturer technical document
Covers Frequency, Maximum breaker size, Maximum fuse size, Minimum circuit ampacity, Phase, Voltage and more
- Panasonic Corporation of North America: CS-YM12CKUW & CU-YM12CBUC Panasonic Project Series High Wall submittalSourced - manufacturer technical document
Covers Wi-Fi support
- Air-Conditioning, Heating, and Refrigeration Institute: AHRI public detail 218027961 for CS-YM12CKUW / CU-YM12CBUCSourced - AHRI directory
Covers AHRI certification number, Rated cooling capacity, COP at 5F, EER2, Rated heating capacity, HSPF2 (Region 4) and more
- ENERGY STAR: ENERGY STAR record 4520552 for CU-YM12CBUC / CS-YM12CKUWSourced - Energy Star listing
Covers Energy Star status
Last updated
Jul 23, 2026