SplitAtlas

ACiQ / Multi-Zone Standard Series

ACiQ Standard 18k R-454B 208/230V 2-Zone Mini-Split

Certified capacity
18,000 BTU/h[3]
SEER2
25.1 SEER2[3]
Heating floor
-13 F[1]
Voltage
230 V[1]
Install path
Professional install

The ACiQ Multi-Zone Standard Series 2-Zone 18k is the middle R-454B line, two heads on one 208/230V outdoor unit. It is stocked/purchasable, a priced condenser you can buy rather than a dealer quote, with professional installation still required.

Certified numbers are SEER2 25.1, EER2 14, HSPF2 9.8 - strong efficiency for the middle tier - and it is ENERGY STAR certified and AHRI cold-climate designated. Cooling capacity is 18000 BTU.

Heating falls through the cold - 19000 BTU at 47F, down to 16000 at 17F and 13500 at 5F.

2 zonesProfessional installCurrent

Refrigerant generation

R-454B - current-generation refrigerant

Paid link

$1,500 / Checked Jul 29, 2026

$1,500 at HVACDirect

Need this installed?

Get installation quotes
Error Codes
ACiQ Multi-Zone Standard Series 2-Zone 18,000 BTU R-454B 208/230V (ES-18Z-M3C) mini-split heat pump outdoor condenser

Image: HVACDirect

Data completeness: 100%
Last sourced
Jul 29, 2026

SplitAtlas score

8.6 / 10

Methodology
Cooling efficiencyTop 10%

(25.1 SEER2) among 18k systems

Heating efficiencyBelow average

(9.8 HSPF2) among 18k systems

Cold-weather performanceBelow average

(5F certified capacity: 71.1% of the 47F rating; -13 F heating floor) among 18k systems

WarrantyTop 10%

(7 yr parts / 12 yr compressor) across the catalogue

Feature setAbove average

(6 verified features) across the catalogue

Price-to-performanceAbove average

($1,500 median retail) among 18k systems

Documentation & partsBelow average

(9 manuals; spec sheet) across the catalogue

Not evaluated

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

    professional install - DIY-accessibility not applicable

Key ratings

Rated cooling

18,000BTU/hNon-Ducted Indoor Units[3]

Rated heating

19,000BTU/hNon-Ducted Indoor Units[3]

Buyer review snapshot

Best for / skip if

Best for

  • 2-zone projects in the 18k outdoor capacity class.
  • Top efficiency shortlists; SEER2 is 25.1.

Install difficulty

Complex professional install
  • Electrical: 230V; MCA 16 A; breaker/fuse 20 A.
  • Line set: connection type not sourced; precharged 24.6 ft; max 196.8 ft.
  • 2-zone condenser; indoor-head matching and branch layout are part of the job.

Availability and price context

  • Last seen at HVACDirect on Jul 29, 2026: $1,499.99. Open the listing for today's price.

Source date

Model data sourced
Jul 29, 2026
Page reviewed
Jul 29, 2026
Source-backed records
5
Newest source retrieved
Jul 29, 2026

Warranty tiers

Registered
7 yr parts / 12 yr compressor - published per-line ACiQ registration terms

The score uses Registered. Additional published terms are shown for reference and not counted in the score.

Review methodology

Model context

Install path
This is professional-install equipment; the listed price is for the equipment, so add installation labor.
Structured ratings
Certification: ENERGY STAR certified, ENERGY STAR cold-climate certified and AHRI cold-climate designated. Refrigerant: current low-GWP R-454B. Minimum heating ambient: -13 F.

Strengths

  • Certified SEER2 25.1 / EER2 14 / HSPF2 9.8 - strong efficiency for the middle line.
  • Stocked/purchasable, a priced R-454B condenser you can buy.
  • R-454B on the value Standard tier.

Weaknesses

  • Heating falls in the cold - 13500 BTU by 5F, below the 19000 at 47F.
  • Two zones is the smallest step.

Climate suitability

Minimum heating ambient
-13 F[1]
Certified heating at 5F
13,500 BTU/hNon-Ducted Indoor Units[3]
Rated heating at 17F
16,000 BTU/hNon-Ducted Indoor Units[3]
Rated heating at 47F
19,000 BTU/hNon-Ducted Indoor Units[3]

Specifications

Show
Manufacturer
ACiQ
Brand
ACiQ
Product line
Multi-Zone Standard Series
Model number
ES-18Z-M3C
Indoor unit model
Depends on the indoor units you choose
Outdoor unit model
ES-18Z-M3C
Number of zones
2
Max indoor units
2 units[2]
Rated cooling capacity
18,000 BTU/hNon-Ducted Indoor Units[3]
Rated heating capacity
19,000 BTU/hNon-Ducted Indoor Units[3]
Voltage
230 V[1]
MCA
16 A[1]
Maximum fuse or breaker size
20 A[1]
Breaker needed
not published
SEER2
25.1 SEER2Non-Ducted Indoor Units[3]
EER2
14 EER2Non-Ducted Indoor Units[3]
HSPF2 (Region 4)
9.8 HSPF2Non-Ducted Indoor Units[3]
HSPF2 (Region 5)
Varies by indoor-unit combination
COP
not published
COP at 47F
not published
COP at 5F
2.3 COPNon-Ducted Indoor Units[3]
Minimum outdoor heating temperature
-13 F[1]
Minimum outdoor cooling temperature
-13 F[1]
Maximum outdoor temperature
122 F[1]
Indoor noise range
Depends on the indoor units you choose
Outdoor noise rating
59.5 dBA[1]
Indoor weight
Depends on the indoor units you choose
Outdoor weight
100.53 lb[1]
Refrigerant
R-454B[3]
Refrigerant charge
61.73 oz[1]
Manufacturer coverage
not published
Line-set size
3 x 1/4 in liquid / 3 x 3/8 in suction
Included line-set length
Depends on the indoor units you choose
Maximum line-set length
196.8 ft[1]
Max line set per indoor
98.4 ft[1]
Maximum elevation difference
49.2 ft[1]
Max height between indoor units
ACiQ R-454B submittal extraction for this outdoor-only condenser did not publish a universal indoor-to-indoor height limit; selected indoor configuration governs.
Wi-Fi support
Depends on the indoor units you choose
Energy Star status
ENERGY STAR certified[4]
AHRI certification number
216032376Non-Ducted Indoor Units[3]
Warranty
Registered: 7 yr parts / 12 yr compressor (published per-line ACiQ registration terms). Score uses Registered.. 12-year compressor / 7-year parts warranty with ACiQ registration terms.
Install path
Professional install
Retail price
$1,499.99
Available retailers
HVACDirect
Manual links
AHRI public detail 216032376, ACiQ R454B Multi-Zone Compatibility Chart, ENERGY STAR exact lookup 216032376, ACiQ multi-zone installation and owner manual, ACiQ Multi-Zone Standard Series official category for ES-18Z-M3C, HVACDirect exact condenser listing for ES-18Z-M3C, ACiQ multi-zone service manual, ACiQ ES-18Z-M3C non-ducted multi-zone submittal
Specification sheet
ACiQ ES-18Z-M3C non-ducted multi-zone submittal
Last sourced date
Jul 29, 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

$1,500 at HVACDirect

$1,500 / Checked Jul 29, 2026

Compatible indoor units

This is an outdoor unit. You choose its indoor heads separately - up to the maximum this condenser supports - and you can mix room sizes and styles across the zones. The models below are the heads this unit is documented to pair with.

  • Ceiling cassette air handlers

    9k, 12k, 18k

    Model numbers
    • 9k: ACiQ-09CC-HH-MC
    • 12k: ACiQ-12CC-HH-MC
    • 18k: ACiQ-18CC-HH-MC

  • Concealed duct air handlers

    9k, 12k

    Model numbers
    • 9k: ACiQ-09CD-HH-MC
    • 12k: ACiQ-12CD-HH-MC

  • Floor console / floor-ceiling air handlers

    9k, 12k, 18k

    Model numbers
    • 9k: ACiQ-09FM-HH-MD
    • 12k: ACiQ-12FM-HH-MD
    • 18k: ACiQ-18FM-HH-MD

  • Slim ceiling cassette air handlers

    18k

    Model numbers
    • 18k: SCC-18-HH-MB

  • Wall-mounted air handlers

    6k, 9k, 12k, 18k

    Model numbers
    • 6k: ACiQ-06W-HH-MD
    • 9k: ACiQ-09W-HH-MD
    • 12k: ACiQ-12W-HH-MD
    • 18k: ACiQ-18W-HH-MD

Sizing note: do not just add up the rooms. Multi-zone condensers have a maximum total connected capacity, and connecting more head capacity than the unit is rated for is a common installer mistake that hurts efficiency and comfort. Match total head capacity to the condenser's rating.

Electrical requirements

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

Installation considerations

Show
Liquid line
3 x 1/4 in[1]
Suction line
3 x 3/8 in[1]
Line connection type
not published
Precharged length
24.6 ft[1]
Included line-set length
Depends on the indoor units you choose
Maximum line-set length
196.8 ft[1]
Max line set per indoor
98.4 ft[1]
Max height between indoor units
ACiQ R-454B submittal extraction for this outdoor-only condenser did not publish a universal indoor-to-indoor height limit; selected indoor configuration governs.
Indoor dimensions
Depends on the indoor units you choose
Outdoor dimensions
35.04 x 13.46 x 26.50 in[1]
Indoor weight
Depends on the indoor units you choose
Outdoor weight
100.53 lb[1]
Drain size
not published

Related systems and guides

Frequently asked questions

Can I install the ACiQ Multi-Zone Standard Series 2-Zone 18,000 BTU R-454B 208/230V (ES-18Z-M3C) myself, or do I need a pro?
ACiQ Multi-Zone Standard Series 2-Zone 18,000 BTU R-454B 208/230V (ES-18Z-M3C) 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 Multi-Zone Standard Series 2-Zone 18,000 BTU R-454B 208/230V (ES-18Z-M3C) keep heating in a cold winter?
The AHRI/ENERGY STAR certification lists 13,500 BTU/h of heating capacity at 5F. Rated heating operation extends down to -13 F. Certified heating efficiency is 9.8 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 ACiQ Multi-Zone Standard Series 2-Zone 18,000 BTU R-454B 208/230V (ES-18Z-M3C) need?
Published electrical requirements: 230 V voltage, 16 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.
How far can the outdoor unit be from the indoor head?
The published maximum line-set length from the outdoor unit to one indoor head is 98.4 ft. The combined piping limit across all heads is 196.8 ft. The outdoor unit's factory charge covers up to 24.6 ft of line; longer runs need added refrigerant. Measure the planned routing before ordering.
What warranty does the ACiQ Multi-Zone Standard Series 2-Zone 18,000 BTU R-454B 208/230V (ES-18Z-M3C) carry?
The manufacturer publishes these warranty tiers: Registered: 7 yr parts / 12 yr compressor (published per-line ACiQ registration terms). Score uses Registered.. Registration requirements and proof of qualified installation commonly affect coverage, so read the warranty terms before install day.

Data sources

Show
  1. ACiQ: ACiQ ES-18Z-M3C non-ducted multi-zone submittalSourced - manufacturer technical document

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

  2. ACiQ: ACiQ Multi-Zone Standard Series official categorySourced - manufacturer product page

    Covers Max indoor units, product_line.name

  3. AHRI certificate #216032376 - search the AHRI DirectorySourced - AHRI directory

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

  4. ENERGY STAR: ENERGY STAR exact row check for AHRI 215735288Sourced - Energy Star listing

    Covers performance_spec.energy_star_cold_climate, Energy Star status

  5. HVACDirect: HVACDirect exact condenser listing for ES-18Z-M3CSourced - retailer listing

    Covers Retail price

  6. ACiQ R454B Multi-Zone Compatibility ChartSourced - manual

    Covers Manual links

Last updated

Jul 29, 2026