Carrier / Infinity 27
Carrier Infinity 27 9k R-454B 208/230V Mini-Split
This 9,000 BTU Infinity 27 on 230V and R-454B leads the series on cooling efficiency at 27.5 SEER2, with 15.5 EER2 and 12.5 HSPF2. Heating holds dead flat at 12,000 BTU at 47F, 12,000 BTU at 17F, and 11,500 BTU at 5F. It is ENERGY STAR certified and cold-climate designated.
Refrigerant generation
R-454B - current-generation refrigerant
This brand doesn't honor its warranty on systems bought online. Buy it through a local contractor who installs it: get quotes from installers in your area, and ask whether they're an authorized dealer for this brand.
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Image: Carrier
- Last sourced
- Jul 27, 2026
SplitAtlas score
9.0 / 10
(27.5 SEER2) among <=9k systems
(12.5 HSPF2) among <=9k systems
(5F certified capacity: 95.8% of the 47F rating; -22 F heating floor) among <=9k systems
(10 yr parts, no separate compressor term) across the catalogue
(6 verified features) across the catalogue
(6 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
- Top efficiency shortlists; SEER2 is 27.5.
Install difficulty
- Electrical: 230V.
Availability and price context
- Carrier doesn't honor its warranty on systems bought online. Buy it through an authorized dealer or contractor.
Purchase channel policy
Carrier's ductless warranty excludes products purchased over the Internet; buyers should treat public online carts as outside the warranty-covered purchase channel.
- Warranty consequence
- Warranty coverage does not apply to any product purchased over the Internet.
- Authorized channel
- Licensed HVAC technician installation with defective parts returned to the distributor through a registered servicing dealer; not an internet purchase.
Any online offer for this brand should be treated as a warranty-risk warning, not a recommendation.
Compare online-purchase warranty rules by brand
Source: Carrier Corporation: CAC/BDP Limited Warranty Certificate - Limited Warranty for Ductless Split Units; retrieved Aug 15, 2026.
Source date
- Model data sourced
- Jul 27, 2026
- Page reviewed
- Jul 27, 2026
- Source-backed records
- 5
- Newest source retrieved
- Sep 12, 2026
Warranty tiers
- Registered
- 10 yr parts / no separate compressor term - eligible timely registered residential installation
- Dealer alternative
- 5 yr parts / no separate compressor term - Consumer Choice dealer alternative: 5-year parts plus 3-year labor through a participating dealer
The score uses Registered. Additional published terms are shown for reference and not counted in the score.
Model context
- Structured ratings
- Certification: ENERGY STAR certified and AHRI cold-climate designated. Refrigerant: current low-GWP R-454B.
Strengths
- High 27.5 SEER2 and a strong 15.5 EER2 in a compact premium head.
- Heat stays flat at 12,000 BTU from 47F through 17F and barely dips at 5F, a genuine cold-climate advantage.
- Cold-climate and ENERGY STAR certified with Carrier's premium warranty and dealer backing.
Weaknesses
- Premium pricing that only pays off where efficiency and deep-cold heat are priorities.
- 230V only, requiring the appropriate dedicated circuit.
Climate suitability
- Minimum heating ambient
- -22 F[4]
- Certified heating at 5F
- 11,500 BTU/h[2]
- Rated heating at 17F
- 12,000 BTU/h[2]
- Rated heating at 47F
- 12,000 BTU/h[2]
Specifications
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- Manufacturer
- Carrier
- Brand
- Carrier
- Product line
- Infinity 27
- Model number
- 45MAHAQ09XA3 indoor / 37MAHAQ09AA3 outdoor
- Indoor unit model
- 45MAHAQ09XA3
- Outdoor unit model
- 37MAHAQ09AA3
- Number of zones
- 1
- Max indoor units
- not published
- Rated cooling capacity
- 9,000 BTU/h[2]
- Rated heating capacity
- 12,000 BTU/h[2]
- Voltage
- 230 V[1]
- MCA
- Not published for this model
- Maximum fuse or breaker size
- Not published for this model
- Breaker needed
- not published
- SEER2
- 27.5 SEER2[2]
- EER2
- 15.5 EER2[2]
- HSPF2 (Region 4)
- 12.5 HSPF2[2]
- HSPF2 (Region 5)
- not published
- COP
- not published
- COP at 47F
- not published
- COP at 5F
- 1.8 COP[2]
- Minimum outdoor heating temperature
- -22 F[4]
- Minimum outdoor cooling temperature
- -22 F[4]
- Maximum outdoor temperature
- 122 F[4]
- Indoor noise range
- Not published for this model
- Outdoor noise rating
- Not published for this model
- Indoor weight
- Not published for this model
- Outdoor weight
- Not published for this model
- Refrigerant
- R-454B[2]
- Refrigerant charge
- not published
- Manufacturer coverage
- not published
- Line-set size
- Not published for this model liquid / Not published for this model suction
- Included line-set length
- Professional installations use separately selected line sets
- Maximum line-set length
- Not published for this model
- Max line set per indoor
- not published
- Maximum elevation difference
- Not published for this model
- Max height between indoor units
- not published
- Wi-Fi support
- Not published for this model
- Energy Star status
- ENERGY STAR certified[3]
- AHRI certification number
- 215323743[2]
- Warranty
- Registered: 10 yr parts / no separate compressor term (eligible timely registered residential installation); Dealer alternative: 5 yr parts / no separate compressor term (Consumer Choice dealer alternative: 5-year parts plus 3-year labor through a participating dealer). Score uses Registered. Additional published terms are shown for reference and not counted in the score.. Consumer Choice Warranty: 10-year parts-only or 5-year parts plus 3-year labor for eligible timely registered residential installations; terms and participating dealer requirements apply.
- Install path
- Professional install
- Retail price
- online listing with warranty risk: $2,559.99
- Available retailers
- HVACDirect
- Manual links
- AHRI public directory record 215323743, ENERGY STAR exact check 215323743, Infinity 27 installation documentation locator, Carrier Infinity 27 Mini Split Heat Pump, AHRI Appendix M1 public detail 215323743
- Specification sheet
- AHRI Appendix M1 public detail 215323743
- Last sourced date
- Jul 27, 2026
Retail purchase context
Warranty consequence
Warranty coverage does not apply to any product purchased over the Internet.
Any online offer for this brand should be treated as a warranty-risk warning, not a recommendation.
Authorized channel: Licensed HVAC technician installation with defective parts returned to the distributor through a registered servicing dealer; not an internet purchase.
Some retailer links may earn us a commission at no extra cost; paid relationships never change scores or recommendations. Affiliate disclosure
Paid link
Warranty-risk online listing
Last seen at HVACDirect on Jul 27, 2026: $2,560
Electrical requirements
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- Voltage
- 230 V[1]
- Voltage range
- 208/230V[1]
- Phase
- 1[1]
- Frequency
- 60 Hz[1]
- MCA
- Not published for this model
- Breaker needed
- not published
- Maximum breaker size
- Not published for this model
- Maximum fuse size
- Not published for this model
- Maximum cooling current
- not published
- Maximum heating current
- not published
- Manufacturer wire notes
- not published
Installation considerations
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- Liquid line
- Not published for this model
- Suction line
- Not published for this model
- Line connection type
- not published
- Precharged length
- not published
- Included line-set length
- Professional installations use separately selected line sets
- Maximum line-set length
- Not published for this model
- Max line set per indoor
- not published
- Max height between indoor units
- not published
- Indoor dimensions
- Not published for this model
- Outdoor dimensions
- Not published for this model
- Indoor weight
- Not published for this model
- Outdoor weight
- Not published for this model
- Drain size
- not published
Related systems and guides
- More Carrier systems
- Carrier Comfort 22 9k R-454B 208/230V Mini-Split
- Carrier Infinity 35 9k R-454B 208/230V Mini-Split
- Carrier Comfort 22 9k R-454B 115V Mini-Split
- Carrier Infinity Legacy 9k A/A R-410A 208/230V Mini-Split
Previous generation
- Guide library
- Mini split buying guide
- Single-zone vs multi-zone mini splits
- Troubleshooting
- Do mini splits work in cold weather?
- Carrier mini split review: is Carrier any good?
- The best 9,000 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)
- Mini split not heating
- Mini split indoor unit freezing up
- Mini split remote not working
- Mini split condensate pump problems
- Mini split Wi-Fi not connecting
- Line sets
- Line-set covers
Frequently asked questions
- Can I install the Carrier Infinity 27 9,000 BTU R-454B 208/230V (45MAHAQ09XA3 / 37MAHAQ09AA3) myself, or do I need a pro?
- Carrier Infinity 27 9,000 BTU R-454B 208/230V (45MAHAQ09XA3 / 37MAHAQ09AA3) 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 Carrier Infinity 27 9,000 BTU R-454B 208/230V (45MAHAQ09XA3 / 37MAHAQ09AA3) keep heating in a cold winter?
- The AHRI/ENERGY STAR certification lists 11,500 BTU/h of heating capacity at 5F. Certified heating efficiency is 12.5 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 Carrier Infinity 27 9,000 BTU R-454B 208/230V (45MAHAQ09XA3 / 37MAHAQ09AA3) need?
- Published electrical requirements: 230 V voltage. Confirm the final circuit against the unit nameplate and local code with a licensed electrician.
- What warranty does the Carrier Infinity 27 9,000 BTU R-454B 208/230V (45MAHAQ09XA3 / 37MAHAQ09AA3) carry?
- The manufacturer publishes these warranty tiers: Registered: 10 yr parts / no separate compressor term (eligible timely registered residential installation); Dealer alternative: 5 yr parts / no separate compressor term (Consumer Choice dealer alternative: 5-year parts plus 3-year labor through a participating dealer). Score uses Registered. Additional published terms are shown for reference and not counted in the score.. Registration requirements and proof of qualified installation commonly affect coverage, so read the warranty terms before install day.
Data sources
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- Carrier Corporation: Carrier Infinity 27 Mini Split Heat PumpSourced - manufacturer product page
Covers Frequency, Phase, Voltage, Voltage range, Additional compressor warranty status, Additional published warranty conditions and more
- Air-Conditioning, Heating, and Refrigeration Institute: AHRI Appendix M1 public detail for 37MAHAQ09AA3 / 45MAHAQ09XA3Sourced - AHRI directory
Covers AHRI certification number, performance_spec.cold_climate_designation, Rated cooling capacity, COP at 5F, EER2, Rated heating capacity and more
- ENERGY STAR: ENERGY STAR exact row check for AHRI 215323743Sourced - Energy Star listing
Covers Energy Star status
- Carrier Corporation: 37MAHA Product Data (37MAHA_D5CSHAH-01PD)Sourced - manufacturer technical document
Covers Minimum outdoor cooling temperature, Minimum outdoor heating temperature, Maximum outdoor temperature
- HVACDirect: HVACDirect exact Carrier offer for 37MAHAQ09AA3 / 45MAHAQ09XA3Sourced - retailer listing
Covers Retail price
Last updated
Jul 27, 2026