Photo may vary slightly — verify by model number before ordering.LG KSUJB121A 12,000 BTU Mid-Static Ducted Single-Zone Heat Pump System, R32, 16.40 SEER2 (KNUJB121A + KUSXB121A)
Not sure it's the right unit? Send the model and serial — help@totalhvacparts.com or 302-219-4994.
Min. order: 1 unit · Weight: 151.1 lb · Truck Freight
Overview
LG KSUJB121A is the complete 12,000 BTU (1 Ton) R32 single-zone mid-static ducted mini split heat pump system from LG's Mid-Static Ducted line: the KNUJB121A indoor unit and the KUSXB121A inverter outdoor unit, sold together as the matched, AHRI-rated pair. It is rated 16.40 SEER2, 12.00 EER2, 10.50 HSPF2, runs on 208-230/60/1 power (13.4 A MCA / 15 A MOP), and is the direct R32 replacement for the R-410A LH128HV1 (LHN128HV1 + LUU120HV).
Capacity modulates across 4,640 / 12,000 / 14,000 Btu/h in cooling and 6,400 / 15,000 / 17,800 Btu/h in heating (min / rated / max), so the system idles at part load instead of cycling. Heating continues down to -4°F outdoor, with 13,100 Btu/h available at 17°F and 11,000 Btu/h at 5°F. The indoor unit runs as low as 28 dB(A); the outdoor unit is 49 dB(A) in cooling.
Features
- Inverter (Variable Speed Auto Changeover
- Compressor) Night Quiet Operation
- Internal Condensate Pump Optional Wi-Fi Control
- Jet Cool / Jet Heat Optional Drain Pan Heater
- Auto Restart Direct / Indirect Wind
- Smart Mode
- Refresh Mode
What's in the bundle
- 1 × LG KNUJB121A 12,000 BTU mid-static ducted indoor unit indoor unit
- 1 × LG KUSXB121A R32 inverter heat pump outdoor unit
What you still need
- 1/4 × 3/8 line set, 16.4 / 65.6 ft
- Interconnect cable, disconnect and breaker sized to the MCA/MOP in the specifications; pad or wall bracket; condensate drain
Typical coverage is roughly 450–550 sq ft depending on climate, insulation and layout. AHRI reference 214826534 (Energy Star, Energy Star Cold Climate). Installation and warranty registration should be completed by a licensed contractor who has completed LG training; the LG limited warranty document is linked under Documentation.
What's Included
This system ships as the LG-matched pair below. Each component is also sold separately — see Companion Units further down.
- Includes KNUJB121A indoor unit
- Includes KUSXB121A outdoor unit
Specifications
Documentation
Companion Units & System Bundle
After You Order
Order number and confirmation by email the moment you check out.
In-stock parts are pulled from our shelf and ship the same business day when ordered before 1pm ET, Mon–Fri. Lead-time parts ship by the date shown on their product page — if that changes, we tell you before it ships.
Tracking number lands in your inbox the moment it leaves the building.
Check the part number on the label against your order before installing. Wrong or damaged? Tell us — we'll sort it out.
Ask the Parts Desk
Not sure this fits? Need more than what's in stock? Send the model and serial from the unit's data plate — a real person reads it and confirms before you order.
Common Questions
What is included with the KSUJB121A system?
KSUJB121A ships as Includes KNUJB121A indoor unit and Includes KUSXB121A outdoor unit. Line set, interconnect wiring, disconnect, pad or bracket and condensate drain are field supplied.
What does the KSUJB121A replace?
KSUJB121A is LG's current R32 model in this position and replaces the discontinued LH128HV1, LHN128HV1 + LUU120HV. R32 and R-410A equipment cannot be mixed — replace the indoor and outdoor unit together.
What power does the KSUJB121A need?
208-230V, 1-phase. Minimum circuit ampacity and maximum overcurrent protection are listed in the Specifications table above and on the LG submittal under Documentation; size the breaker and wire to those values and local code.
Is the submittal sheet and installation manual available for KSUJB121A?
Yes — the LG submittal data sheet, engineering manual, installation manual and warranty document are all linked under Documentation on this page and can be downloaded without an account.
Is the stock number on this page real?
Yes — it's the live count from our own shelf, not an availability estimate. If it says 1, that's how many are physically here. When it hits zero, this page says so.
Is this a genuine LG unit, or aftermarket?
Genuine LG OEM equipment — not an aftermarket substitute.
I see this listed under a different name on other sites. Is it the same part?
Yes — manufacturers and distributors sometimes use different brand names or legacy labels for the same part number. Part number KSUJB121A is identical across all name variations.
What's the warranty on this part?
Warranty terms vary by manufacturer. Contact us with your order number for details specific to this part.
How fast does this ship?
In-stock items ship the same business day on orders placed before 1pm ET, Monday–Friday. Standard ground delivers to most of the continental US in 2–5 business days. This part ships by LTL freight, so transit runs on the freight schedule — we'll contact you to arrange delivery.
Does everything ship UPS or FedEx Ground?
This part ships by truck freight rather than parcel — still free, included in the price shown, and we'll contact you to schedule delivery before it ships.Most orders ship UPS or FedEx Ground. A small number of large or heavy parts across the catalog ship by truck freight instead — that's still free, and we reach out to arrange a delivery window before those orders leave the warehouse.