SplitAtlas

LG / 1-Way Ceiling Cassette R-32

LG 1-Way Ceiling Cassette 18k One-Way Cassette R-32 208/230V Mini-Split

Certified capacity
18,000 BTU/h[3]
SEER2
20.5 SEER2[3]
Heating floor
-4 F[1]
Voltage
208/230V[1]
Install path
Professional install

The 1-Way Ceiling Cassette R-32 18k pairs KNUFB181A with KUSXB181A for a professional 1-way ceiling cassette installation instead of a wall-mounted head. It certifies at 18,000 BTU cooling and 19,000 BTU heating at 47F, with 20.5 SEER2, 12.2 EER2, and 9.5 HSPF2.

Its certified 5F output is 14,600 BTU, above the 17F rating, so it has real low-temperature heat to size against. LG also has an LGRED 18k 1-Way Ceiling Cassette pairing; that version reaches 17,000 BTU at 5F, while this one is the moderate-climate choice at 14,600 BTU.

The catch is ceiling execution: joist clearance, condensate lift, service access, and throw direction matter more than they would on a wall head.

1 zoneProfessional installCurrent

Refrigerant generation

R-32 - current-generation refrigerant

This system's warranty depends on licensed installation — get quotes from installers in your area.

Get installation quotes
Error Codes
Data completeness: 82%
Last sourced
Aug 5, 2026

SplitAtlas score

7.8 / 10

Methodology
Cooling efficiencyBelow average

(20.5 SEER2) among 18k systems

Heating efficiencyBottom quartile

(9.5 HSPF2) among 18k systems

Cold-weather performanceBelow average

(5F certified capacity: 76.8% of the 47F rating; -4 F heating floor) among 18k systems

WarrantyTop quartile

(10 yr parts / 10 yr compressor) across the catalogue

Feature setBottom quartile

(3 verified features) across the catalogue

Documentation & partsBelow average

(3 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.

    Get a quote

Key ratings

Rated cooling

18,000BTU/h[3]

Rated heating

19,000BTU/h[3]

Best-fit use cases

Best for narrow rooms, perimeter offices, and ceiling bays where single-direction throw is more useful than a centered wall head around 650-900 sq ft, where LG dealer installation and the alternate indoor form are worth more than the simplicity of a wall-mounted head.

Buyer review snapshot

Install difficulty

Professional install
  • Electrical: 208/230V; MCA 11.5 A; breaker/fuse 25 A.
  • Line set: connection type not sourced; max 164 ft.

Alternatives

Availability and price context

This system needs a professional install, and its warranty depends on who installs it. Its real price is an installed quote that depends on your home, so get installation quotes to price it.

Purchase channel policy

LG allows the online-purchase path only when the online source is expressly authorized by LG; an online purchase from a non-authorized source voids the limited warranty.

Warranty impact
The limited warranty is void and LG has no liability when the system is purchased online from a source not expressly authorized by LG.
Installation condition
The online source must be expressly authorized by LG; the system must also satisfy LG's qualified-system installation terms.
Authorized channel
Expressly authorized LG source with qualified installation by a trained, licensed HVAC contractor under LG warranty terms.

Buying online can keep warranty coverage only when the seller is expressly authorized by LG; confirm that status and the qualified installation path before purchase.

Compare online-purchase warranty rules by brand

Source: LG Electronics U.S.A., Inc.: LG R32 Residential / Light Commercial Systems Warranty Card; retrieved Aug 15, 2026.

Source date

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

Warranty tiers

Base
5 yr parts / 7 yr compressor - standard coverage
Registered
10 yr parts / 10 yr compressor - registration within 60 days of startup, by an installer with current LG training and an HVAC license

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

Review methodology

Strengths

  • 18,000 BTU of 1-way ceiling cassette cooling capacity on current R-32 refrigerant.
  • 20.5 SEER2 / 12.2 EER2 / 9.5 HSPF2 certified efficiency.
  • 12,000 BTU at 17F and 14,600 BTU at 5F give concrete winter numbers for sizing.

Weaknesses

  • The catch is ceiling execution: joist clearance, condensate lift, service access, and throw direction matter more than they would on a wall head.
  • Ceiling cassettes need a workable ceiling cavity, drain route, and service clearance, so they are not a drop-in wall-head substitute.

Climate suitability

Minimum heating ambient
-4 F[1]
Certified heating at 5F
14,600 BTU/h[3]
Rated heating at 17F
12,000 BTU/h[3]
Rated heating at 47F
19,000 BTU/h[3]

Specifications

Show
Manufacturer
LG
Brand
LG
Product line
1-Way Ceiling Cassette R-32
Model number
KNUFB181A indoor / KUSXB181A outdoor
Indoor unit model
KNUFB181A
Outdoor unit model
KUSXB181A
Number of zones
1
Max indoor units
not published
Rated cooling capacity
18,000 BTU/h[3]
Rated heating capacity
19,000 BTU/h[3]
Voltage
208/230V[1]
MCA
11.5 A[1]
Maximum fuse or breaker size
25 A[1]
Breaker needed
not published
SEER2
20.5 SEER2[3]
EER2
12.2 EER2[3]
HSPF2 (Region 4)
9.5 HSPF2[3]
HSPF2 (Region 5)
not published
COP
not published
COP at 47F
not published
COP at 5F
1.8 COP[3]
Minimum outdoor heating temperature
-4 F[1]
Minimum outdoor cooling temperature
5 F[1]
Maximum outdoor temperature
118 F[1]
Indoor noise range
not published
Outdoor noise rating
not published
Indoor weight
not published
Outdoor weight
not published
Refrigerant
R-32[3]
Refrigerant charge
not published
Manufacturer coverage
not published
Line-set size
3/8" O.D. liquid / 5/8" O.D. suction
Included line-set length
LG cassette and ducted submittals publish piping limits; the installing contractor supplies the refrigerant line set.
Maximum line-set length
164 ft[1]
Max line set per indoor
not published
Maximum elevation difference
98.4 ft[1]
Max height between indoor units
not published
Wi-Fi support
supported[2]
Energy Star status
ENERGY STAR certified[4]
AHRI certification number
216778957[3]
Warranty
Base: 5 yr parts / 7 yr compressor (standard coverage); Registered: 10 yr parts / 10 yr compressor (registration within 60 days of startup, by an installer with current LG training and an HVAC license). Score uses Registered.. Standard 5-year parts and 7-year compressor coverage; qualified registered installations extend to 10 years total parts and compressor coverage.
Install path
Professional install
Retail price
Installed quote only
Available retailers
not published
Manual links
AHRI Active public directory row 216778957, LG ProductSearch record for KSUFB181A, LG 1-Way Ceiling Cassette R-32 submittal - KSUFB181A
Specification sheet
LG 1-Way Ceiling Cassette R-32 submittal - KSUFB181A
Last sourced date
Aug 5, 2026

Electrical requirements

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

Installation considerations

Show
Liquid line
3/8" O.D.[1]
Suction line
5/8" O.D.[1]
Line connection type
not published
Precharged length
not published
Included line-set length
LG cassette and ducted submittals publish piping limits; the installing contractor supplies the refrigerant line set.
Maximum line-set length
164 ft[1]
Max line set per indoor
not published
Max height between indoor units
not published
Indoor dimensions
not published
Outdoor dimensions
not published
Indoor weight
not published
Outdoor weight
not published
Drain size
not published

Related systems and guides

Frequently asked questions

Can I install the LG 1-Way Ceiling Cassette 18,000 BTU R-32 208/230V (KSUFB181A) myself, or do I need a pro?
LG 1-Way Ceiling Cassette 18,000 BTU R-32 208/230V (KSUFB181A) 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 LG 1-Way Ceiling Cassette 18,000 BTU R-32 208/230V (KSUFB181A) keep heating in a cold winter?
The AHRI/ENERGY STAR certification lists 14,600 BTU/h of heating capacity at 5F. Rated heating operation extends down to -4 F. Certified heating efficiency is 9.5 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 LG 1-Way Ceiling Cassette 18,000 BTU R-32 208/230V (KSUFB181A) need?
Published electrical requirements: 208/230V voltage, 11.5 A minimum circuit ampacity, and 25 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 164 ft. Measure the planned routing before ordering.
What warranty does the LG 1-Way Ceiling Cassette 18,000 BTU R-32 208/230V (KSUFB181A) carry?
The manufacturer publishes these warranty tiers: Base: 5 yr parts / 7 yr compressor (standard coverage); Registered: 10 yr parts / 10 yr compressor (registration within 60 days of startup, by an installer with current LG training and an HVAC license). 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. LG Electronics U.S.A., Inc.: LG 1-Way Ceiling Cassette R-32 submittal KSUFB181ASourced - manufacturer technical document

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

  2. LG Electronics U.S.A., Inc.: LG ProductSearch 1-Way Ceiling Cassette recordSourced - manufacturer product page

    Covers Wi-Fi support

  3. Air-Conditioning, Heating, and Refrigeration Institute: AHRI Active LG R-32 form-factor row 216778956Sourced - AHRI directory

    Covers AHRI certification number, Rated cooling capacity, COP at 5F, EER2, Rated heating capacity, HSPF2 (Region 4) and more

  4. ENERGY STAR: ENERGY STAR exact mini-split row 216778956Sourced - Energy Star listing

    Covers Energy Star status

  5. LG Electronics U.S.A., Inc.: LG R32 Residential / Light Commercial Systems Warranty CardSourced - manufacturer technical document

    Covers Legacy compressor warranty value, Legacy warranty value, Registered compressor warranty, Registered warranty conditions, Registered parts warranty, Base compressor warranty and more

Last updated

Aug 5, 2026