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LG / Mid Static Ducted R-32

LG Mid Static Ducted 12k R-32 208/230V Mini-Split

Certified capacity
12,000 BTU/h[3]
SEER2
16.4 SEER2[3]
Heating floor
-4 F[1]
Voltage
208/230V[1]
Install path
Professional install

The Mid Static Ducted R-32 12k pairs KNUJB121A with KUSXB121A for a professional mid static ducted installation instead of a wall-mounted head. It certifies at 12,000 BTU cooling and 15,000 BTU heating at 47F, with 16.4 SEER2, 12 EER2, and 10.5 HSPF2. Its certified 5F output is 11,000 BTU, above the 17F rating, so it has real low-temperature heat to size against.

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

7.9 / 10

Methodology
Cooling efficiencyBottom quartile

(16.4 SEER2) among 12k systems

Heating efficiencyAbove average

(10.5 HSPF2) among 12k systems

Cold-weather performanceBelow average

(73.3% heat retained at 5F; -4 F heating floor) among 12k systems

WarrantyAbove average

(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

12,000BTU/h[3]

Rated heating

15,000BTU/h[3]

Best-fit use cases

Best for rooms where a short concealed duct run can hide the indoor unit and spread air through grilles around 400-600 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

Best for / skip if

Skip if

  • Top-efficiency cooling is the priority; SEER2 is 16.4.

Install difficulty

Professional install
  • Electrical: 208/230V; MCA 9 A; breaker/fuse 15 A.
  • Line set: connection type not sourced; max 65.6 ft.

Alternatives

Availability and price context

We could not verify a current retail price for this model. We could not find this exact model in stock at a retailer we work with when we last checked on 2026-08-05.

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

Warranty: 5 years parts and 7 years compressor as standard; 10 years parts and compressor if qualified registered installation.

Review methodology

Model context

LG dealer channel
LG alternate-form equipment here is professional-install; exact-pair retail offers only appear when we can verify the retailer destination.
Install path
This is professional-install equipment; no verified current retail offer is attached. Brand purchase-channel policy is shown in the buyer review snapshot.
Installation context
Concealed ducted installs depend on duct layout, static pressure, return-air path, condensate routing, and service access.

Strengths

  • 12,000 BTU of mid static ducted cooling capacity on current R-32 refrigerant.
  • 16.4 SEER2 / 12 EER2 / 10.5 HSPF2 certified efficiency.
  • 10,200 BTU at 17F and 11,000 BTU at 5F give concrete winter numbers for sizing.

Weaknesses

  • At 16.4 SEER2 it gives up 5.8 points to LG's 22.2 SEER2 cassette benchmark in the same R-32 batch, so choose the ducted layout for hidden grilles rather than top efficiency.

Climate suitability

Minimum heating ambient
-4 F[1]
Rated heating at 5F
11,000 BTU/h[3]
Rated heating at 17F
10,200 BTU/h[3]
Rated heating at 47F
15,000 BTU/h[3]

Specifications

Show
Manufacturer
LG
Brand
LG
Product line
Mid Static Ducted R-32
Model number
KNUJB121A indoor / KUSXB121A outdoor
Indoor unit model
KNUJB121A
Outdoor unit model
KUSXB121A
Number of zones
1
Max indoor units
not published
Rated cooling capacity
12,000 BTU/h[3]
Rated heating capacity
15,000 BTU/h[3]
Voltage
208/230V[1]
MCA
9 A[1]
Maximum fuse or breaker size
15 A[1]
Breaker needed
not published
SEER2
16.4 SEER2[3]
EER2
12 EER2[3]
HSPF2 (Region 4)
10.5 HSPF2[3]
HSPF2 (Region 5)
not published
COP
not published
COP at 47F
not published
COP at 5F
2.3 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
1/4" O.D. liquid / 3/8" 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
65.6 ft[1]
Max line set per indoor
not published
Maximum elevation difference
49.2 ft[1]
Max height between indoor units
not published
Wi-Fi support
supported[2]
Energy Star status
ENERGY STAR certified[4]
AHRI certification number
214826534[3]
Warranty
Standard: 5 yr parts / 7 yr compressor (standard coverage); Best case: 10 yr parts / 10 yr compressor (qualified registered installation). 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
We could not find this exact model in stock at a retailer we work with when we last checked on 2026-08-05.
Available retailers
not published
Manual links
AHRI Active public directory row 214826534, LG ProductSearch record for KSUJB121A, LG Mid Static Ducted R-32 submittal - KSUJB121A
Specification sheet
LG Mid Static Ducted R-32 submittal - KSUJB121A
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
9 A[1]
Breaker needed
not published
Maximum breaker size
15 A[1]
Maximum fuse size
15 A[1]
Maximum cooling current
not published
Maximum heating current
not published
Manufacturer wire notes
not published

Installation considerations

Show
Liquid line
1/4" O.D.[1]
Suction line
3/8" 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
65.6 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 Mid Static Ducted 12,000 BTU R-32 208/230V (KSUJB121A) myself, or do I need a pro?
LG Mid Static Ducted 12,000 BTU R-32 208/230V (KSUJB121A) 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 Mid Static Ducted 12,000 BTU R-32 208/230V (KSUJB121A) keep heating in a cold winter?
The manufacturer publishes 11,000 BTU/h of heating output at 5F. Rated heating operation extends down to -4 F. Certified heating efficiency is 10.5 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 Mid Static Ducted 12,000 BTU R-32 208/230V (KSUJB121A) need?
Published electrical requirements: 208/230V voltage, 9 A minimum circuit ampacity, and 15 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 65.6 ft. 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 LG Mid Static Ducted 12,000 BTU R-32 208/230V (KSUJB121A) carry?
The manufacturer publishes these warranty tiers: Standard: 5 yr parts / 7 yr compressor (standard coverage); Best case: 10 yr parts / 10 yr compressor (qualified registered installation). 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 Mid Static Ducted R-32 submittal KSUJB121ASourced - 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 Best-case compressor warranty, Best-case warranty conditions, Best-case parts warranty, Legacy compressor warranty value, Legacy warranty value, Standard compressor warranty and more

Last updated

Aug 5, 2026