Carrier / Infinity 35
Carrier Infinity 35 18k R-454B 208/230V Mini-Split
This 1.5-ton Infinity 35 on 230V and R-454B is rated 25.8 SEER2, 15 EER2, and the highest HSPF2 in the whole lineup at 16.2. Its hyper-heat curve rises to 20,000 BTU at 47F, 19,300 BTU at 17F, and 22,600 BTU at 5F. It is ENERGY STAR certified and cold-climate designated.
1 zoneProfessional installCurrent
Refrigerant generation
R-454B - current-generation refrigerant
Image: Carrier
Data completeness: 100%
- Last sourced
- Jul 27, 2026
SplitAtlas score
9.4 / 10
Cooling efficiencyTop 10%
(25.8 SEER2) among 18k systems
Heating efficiencyTop 10%
(16.2 HSPF2) among 18k systems
Cold-weather performanceTop quartile
(100% heat retained at 5F; -22 F heating floor) among 18k systems
WarrantyAbove average
(10 yr parts / 10 yr compressor) across the catalogue
Feature setAbove average
(6 verified features) across the catalogue
Documentation & partsBelow average
(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
quote-only - no retail price to evaluate
Key ratings
Buyer review snapshot
Best for / skip if
Best for
- Top efficiency shortlists; SEER2 is 25.8.
Install difficulty
Professional install
- Electrical: 230V.
Availability and price context
- Warranty warning: Warranty coverage does not apply to any product purchased over the Internet. Online listing: $4,599.99 at HVACDirect; checked Jul 27, 2026; price source is HVACDirect.
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
- 4
- Newest source retrieved
- Jul 27, 2026
Warranty tiers
Warranty: 10 years parts and no separate compressor term published as standard.
Model context
- Structured ratings
- Certification: ENERGY STAR certified and AHRI cold-climate designated. Refrigerant: current low-GWP R-454B. Minimum heating ambient: -22 F.
Strengths
- Lineup-topping 16.2 HSPF2, the best seasonal heating efficiency of any head here.
- Heat climbs to 22,600 BTU at 5F, above its 47F rating, true flagship hyper-heat behavior.
- Cold-climate and ENERGY STAR certified at a whole-room capacity, with Carrier's warranty backing.
Weaknesses
- SEER2 of 25.8 is lower than the smaller Infinity 35 heads, so cooling efficiency, while good, is not class-leading.
- Flagship pricing and 230V wiring requirements apply.
Climate suitability
- Minimum heating ambient
- -22 F[1]
- Rated heating at 5F
- 22,600 BTU/h[2]
- Rated heating at 17F
- 19,300 BTU/h[2]
- Rated heating at 47F
- 20,000 BTU/h[2]
Specifications
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- Manufacturer
- Carrier
- Brand
- Carrier
- Product line
- Infinity 35
- Model number
- 45MPHAQ18XA3 indoor / 37MPRAQ18AA3 outdoor
- Indoor unit model
- 45MPHAQ18XA3
- Outdoor unit model
- 37MPRAQ18AA3
- Number of zones
- 1
- Max indoor units
- not published
- Rated cooling capacity
- 18,000 BTU/h[2]
- Rated heating capacity
- 20,000 BTU/h[2]
- Voltage
- 230 V[1]
- MCA
- No model-specific value is published on the current Carrier consumer listing
- Maximum fuse or breaker size
- No model-specific value is published on the current Carrier consumer listing
- Breaker needed
- not published
- SEER2
- 25.8 SEER2[2]
- EER2
- 15 EER2[2]
- HSPF2 (Region 4)
- 16.2 HSPF2[2]
- HSPF2 (Region 5)
- not published
- COP
- not published
- COP at 47F
- not published
- COP at 5F
- 2.34 COP[2]
- Minimum outdoor heating temperature
- -22 F[1]
- Minimum outdoor cooling temperature
- No model-specific value is published on the current Carrier consumer listing
- Maximum outdoor temperature
- 122 F[1]
- Indoor noise range
- No model-specific value is published on the current Carrier consumer listing
- Outdoor noise rating
- No model-specific value is published on the current Carrier consumer listing
- Indoor weight
- No model-specific value is published on the current Carrier consumer listing
- Outdoor weight
- No model-specific value is published on the current Carrier consumer listing
- Refrigerant
- R-454B[2]
- Refrigerant charge
- not published
- Manufacturer coverage
- not published
- Line-set size
- No model-specific value is published on the current Carrier consumer listing liquid / No model-specific value is published on the current Carrier consumer listing suction
- Included line-set length
- Professional installations use separately selected line sets
- Maximum line-set length
- No model-specific value is published on the current Carrier consumer listing
- Max line set per indoor
- not published
- Maximum elevation difference
- No model-specific value is published on the current Carrier consumer listing
- Max height between indoor units
- not published
- Wi-Fi support
- No model-specific value is published on the current Carrier consumer listing
- Energy Star status
- ENERGY STAR certified[3]
- AHRI certification number
- 215413144[2]
- Warranty
- Standard: 10 yr parts / no separate compressor term (eligible timely registered residential installation). 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: $4,599.99
- Available retailers
- HVACDirect
- Manual links
- AHRI public directory record 215413144, ENERGY STAR exact check 215413144, Infinity 35 installation documentation locator, Carrier Infinity 35 Mini Split Heat Pump with Basepan Heater, HVACDirect exact Carrier affiliate offer carrier-infinity-35-18k-r454b-230v, AHRI Appendix M1 public detail 215413144
- Specification sheet
- AHRI Appendix M1 public detail 215413144
- 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
Listed at HVACDirect: $4,600. Checked Jul 27, 2026; price source HVACDirect.
Electrical requirements
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- Voltage
- 230 V[1]
- Voltage range
- 208/230V[1]
- Phase
- 1[1]
- Frequency
- 60 Hz[1]
- MCA
- No model-specific value is published on the current Carrier consumer listing
- Breaker needed
- not published
- Maximum breaker size
- No model-specific value is published on the current Carrier consumer listing
- Maximum fuse size
- No model-specific value is published on the current Carrier consumer listing
- Maximum cooling current
- not published
- Maximum heating current
- not published
- Manufacturer wire notes
- not published
Installation considerations
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- Liquid line
- No model-specific value is published on the current Carrier consumer listing
- Suction line
- No model-specific value is published on the current Carrier consumer listing
- Line connection type
- not published
- Precharged length
- not published
- Included line-set length
- Professional installations use separately selected line sets
- Maximum line-set length
- No model-specific value is published on the current Carrier consumer listing
- Max line set per indoor
- not published
- Max height between indoor units
- not published
- Indoor dimensions
- No model-specific value is published on the current Carrier consumer listing
- Outdoor dimensions
- No model-specific value is published on the current Carrier consumer listing
- Indoor weight
- No model-specific value is published on the current Carrier consumer listing
- Outdoor weight
- No model-specific value is published on the current Carrier consumer listing
- Drain size
- not published
Related systems and guides
- More Carrier systems
- Carrier Infinity 27 18k 230V
- Infinity 38MPRA/40MPHA legacy 18k
Previous generation
- Comfort 22 18k
- Carrier Infinity 38MPRA/40MPHB legacy 18k 230V
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 18,000 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 35 18,000 BTU R-454B 208/230V (45MPHAQ18XA3 / 37MPRAQ18AA3) myself, or do I need a pro?
- Carrier Infinity 35 18,000 BTU R-454B 208/230V (45MPHAQ18XA3 / 37MPRAQ18AA3) 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 35 18,000 BTU R-454B 208/230V (45MPHAQ18XA3 / 37MPRAQ18AA3) keep heating in a cold winter?
- The manufacturer publishes 22,600 BTU/h of heating output at 5F. Rated heating operation extends down to -22 F. Certified heating efficiency is 16.2 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 35 18,000 BTU R-454B 208/230V (45MPHAQ18XA3 / 37MPRAQ18AA3) need?
- Published electrical requirements: 230 V voltage, No model-specific value is published on the current Carrier consumer listing minimum circuit ampacity, and No model-specific value is published on the current Carrier consumer listing 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 No model-specific value is published on the current Carrier consumer listing. 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 Carrier Infinity 35 18,000 BTU R-454B 208/230V (45MPHAQ18XA3 / 37MPRAQ18AA3) carry?
- The manufacturer publishes these warranty tiers: Standard: 10 yr parts / no separate compressor term (eligible timely registered residential installation). 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 35 Mini Split Heat Pump with Basepan HeaterSourced - manufacturer product page
Covers Frequency, Phase, Voltage, Voltage range, Minimum outdoor heating temperature, Maximum outdoor temperature and more
- Air-Conditioning, Heating, and Refrigeration Institute: AHRI Appendix M1 public detail for 37MPRAQ18AA3 / 45MPHAQ18XA3Sourced - 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 215413144Sourced - Energy Star listing
Covers Energy Star status
- HVACDirect: HVACDirect exact Carrier offer for 37MPRAQ18AA3 / 45MPHAQ18XA3Sourced - retailer listing
Covers Retail price
Last updated
Jul 27, 2026