ACiQ / ACiQ Extreme
ACiQ Extreme 18k R-454B 208/230V Mini-Split
This ton-and-a-half Extreme unit runs R-454B on 230V at 21.4 SEER2, 12.5 EER2, and 11 HSPF2, ENERGY STAR certified and cold-climate designated. Its heating curve is the most striking in the lineup: a dead-flat 18,000 BTU at 47F, 18,000 BTU at 17F, and 18,000 BTU at 5F. It simply does not lose rated capacity as the temperature drops.
Refrigerant generation
R-454B - current-generation refrigerant
Paid link
$1,800 / Fresh price - checked Jul 26, 2026
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Image: ACiQ
- Last sourced
- Jul 26, 2026
SplitAtlas score
8.8 / 10
(21.4 SEER2) among 18k systems
(11.0 HSPF2) among 18k systems
(100% heat retained at 5F; -22 F heating floor) among 18k systems
(19.5 dBA indoor min / 59 dBA outdoor) among 18k systems
(7 yr parts / 12 yr compressor) across the catalogue
(5 verified features) across the catalogue
($1,800 median retail) among 18k systems
(6 manuals; spec sheet) across the catalogue
Not evaluated
- Installation accessibility — not applicable (professional install)N/A
professional install - DIY-accessibility not applicable
Key ratings
Best-fit use cases
Best for a large room or open space on 230V in a severe climate where unwavering heat output through the coldest nights is the priority.
Buyer review snapshot
Install difficulty
- Electrical: 230V; MCA 19 A; breaker/fuse 20 A.
- Line set: connection type not sourced; precharged 25 ft.
Alternatives
- Blueridge XS6 Max Efficiency 18,000 BTU R-454B 208/230V (BXS6A18WM0 / BXS6A18UC0)
9.0 score / 18k / SEER2 25.6 / -22 F heating floor / 230V
Exact destination at Alpine Home Air: $2,359.00, checked Jul 24, 2026
- Senville ELITE 18,000 BTU R-454B 208/230V (SENE-18EL-IHH / SENE-18EL-OH)
8.9 score / 18k / SEER2 25.6 / -22 F heating floor / 187-253V
Exact destination at Senville: $1,899.99, checked Jul 24, 2026
Availability and price context
- Verified current price: $1,799.99 at HVACDirect; availability in_stock; checked Jul 26, 2026.
Source date
- Model data sourced
- Jul 26, 2026
- Page reviewed
- Jul 26, 2026
- Source-backed records
- 3
- Newest source retrieved
- Jul 26, 2026
Warranty tiers
Warranty: 7 years parts and 12 years compressor as standard.
Strengths
- Completely flat 18,000 BTU output from 47F down to 5F - no cold-weather derating at all.
- Cold-climate designated and ENERGY STAR certified, an ideal profile for reliable deep-winter heat.
Weaknesses
- SEER2 of 21.4 is the most modest of the Extreme line, so it trades some peak cooling efficiency for that flat heating curve.
- Value-brand support means fewer local techs are versed in the platform than premium cold-climate brands.
Climate suitability
- Minimum heating ambient
- -22 F[1]
- Rated heating at 5F
- 18,000 BTU/h[2]
- Rated heating at 17F
- 18,000 BTU/h[2]
- Rated heating at 47F
- 18,000 BTU/h[2]
Specifications
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- Manufacturer
- ACiQ
- Brand
- ACiQ
- Product line
- ACiQ Extreme
- Model number
- ACIQ-18W-HH-MD indoor / ACIQ-18ZPL-HP230C outdoor
- Indoor unit model
- ACIQ-18W-HH-MD
- Outdoor unit model
- ACIQ-18ZPL-HP230C
- Number of zones
- 1
- Max indoor units
- not published
- Rated cooling capacity
- 18,000 BTU/h[2]
- Rated heating capacity
- 18,000 BTU/h[2]
- Voltage
- 230 V[1]
- MCA
- 19 A[1]
- Maximum fuse or breaker size
- 20 A[1]
- Breaker needed
- not published
- SEER2
- 21.4 SEER2[2]
- EER2
- 12.5 EER2[2]
- HSPF2 (Region 4)
- 11 HSPF2[2]
- HSPF2 (Region 5)
- not published
- COP
- not published
- COP at 47F
- not published
- COP at 5F
- 1.92 COP[2]
- Minimum outdoor heating temperature
- -22 F[1]
- Minimum outdoor cooling temperature
- -22 F[1]
- Maximum outdoor temperature
- 122 F[1]
- Indoor noise range
- 19.5 / 39.5 dB(A)[1]
- Outdoor noise rating
- 59 dBA[1]
- Indoor weight
- 36.6 lb[1]
- Outdoor weight
- not published
- Refrigerant
- R-454B[2]
- Refrigerant charge
- not published
- Manufacturer coverage
- not published
- Line-set size
- 1/4 in liquid / 1/2 in suction
- Included line-set length
- Line set length is selected as an accessory on this HVACDirect system page.
- Maximum line-set length
- not published
- Max line set per indoor
- not published
- Maximum elevation difference
- not published
- Max height between indoor units
- not published
- Wi-Fi support
- supported[1]
- Energy Star status
- ENERGY STAR certified[3]
- AHRI certification number
- 216032336[2]
- Warranty
- Standard: 7 yr parts / 12 yr compressor (published per-line terms with online registration). 12-year compressor / 7-year parts with online registration
- Install path
- Professional install
- Retail price
- $1,799.99
- Available retailers
- HVACDirect
- Manual links
- AHRI public directory record 216032336, ENERGY STAR exact check 216032336, 18,000 BTU ACiQ Extreme 21.4 SEER2 Single Zone Wall Mount Mini Split Heat Pump System - R454B | 230V HVACDirect installation resources listing, 18,000 BTU ACiQ Extreme 21.4 SEER2 Single Zone Wall Mount Mini Split Heat Pump System - R454B | 230V, HVACDirect exact affiliate offer aciq-extreme-18k-r454b-230v, 18,000 BTU ACiQ Extreme 21.4 SEER2 Single Zone Wall Mount Mini Split Heat Pump System - R454B | 230V HVACDirect product specification grid
- Specification sheet
- 18,000 BTU ACiQ Extreme 21.4 SEER2 Single Zone Wall Mount Mini Split Heat Pump System - R454B | 230V HVACDirect product specification grid
- Last sourced date
- Jul 26, 2026
Retail purchase context
Some retailer links may earn us a commission at no extra cost; paid relationships never change scores or recommendations. Affiliate disclosure
Paid link
$1,800 / Fresh price - checked Jul 26, 2026
Installation considerations
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- 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
- Line set length is selected as an accessory on this HVACDirect system page.
- Maximum line-set length
- not published
- Max line set per indoor
- not published
- Max height between indoor units
- not published
- Indoor dimensions
- 40.06 x 12.60 x 9.72 in[1]
- Outdoor dimensions
- 35.04 x 26.50 x 13.46 in[1]
- Indoor weight
- 36.6 lb[1]
- Outdoor weight
- not published
- Drain size
- not published
Related systems and guides
- More ACiQ systems
- ACiQ Essentials 18k 230V
- ACiQ Multi-Zone Standard Series 18k 230V
- Serena Series Multi-Zone 17.7k
- ACiQ 230 V option
- Guide library
- Mini split buying guide
- Single-zone vs multi-zone mini splits
- Troubleshooting
- Do mini splits work in cold weather?
- ACiQ mini split review: is ACiQ 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 making loud noise
- Mini split not cooling
- Line sets
- Line-set covers
Frequently asked questions
- Can I install the ACiQ Extreme 18,000 BTU R-454B 208/230V (ACIQ-18W-HH-MD / ACIQ-18ZPL-HP230C) myself, or do I need a pro?
- ACiQ Extreme 18,000 BTU R-454B 208/230V (ACIQ-18W-HH-MD / ACIQ-18ZPL-HP230C) 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 ACiQ Extreme 18,000 BTU R-454B 208/230V (ACIQ-18W-HH-MD / ACIQ-18ZPL-HP230C) keep heating in a cold winter?
- The manufacturer publishes 18,000 BTU/h of heating output at 5F. Rated heating operation extends down to -22 F. Certified heating efficiency is 11 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 ACiQ Extreme 18,000 BTU R-454B 208/230V (ACIQ-18W-HH-MD / ACIQ-18ZPL-HP230C) need?
- Published electrical requirements: 230 V voltage, 19 A minimum circuit ampacity, and 20 A maximum breaker or fuse sizing. Confirm the final circuit against the unit nameplate and local code with a licensed electrician.
- What warranty does the ACiQ Extreme 18,000 BTU R-454B 208/230V (ACIQ-18W-HH-MD / ACIQ-18ZPL-HP230C) carry?
- The manufacturer publishes these warranty tiers: Standard: 7 yr parts / 12 yr compressor (published per-line terms with online registration). Registration requirements and proof of qualified installation commonly affect coverage, so read the warranty terms before install day.
Data sources
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- HVACDirect / ACiQ: 18,000 BTU ACiQ Extreme 21.4 SEER2 Single Zone Wall Mount Mini Split Heat Pump System - R454B | 230VSourced - manufacturer product page
Covers Frequency, Maximum breaker size, Maximum fuse size, Minimum circuit ampacity, Phase, Voltage and more
- Air-Conditioning, Heating, and Refrigeration Institute: AHRI Appendix M1 public detail for ACIQ-18ZPL-HP230C / ACIQ-18W-HH-MDSourced - 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 exact row check for AHRI 216032336Sourced - Energy Star listing
Covers Energy Star status
Last updated
Jul 26, 2026