Series photoLG · Single-Zone
~$1,143
LG Mega 9,000 BTU
Mild-climate bedrooms and small offices that want better efficiency than LG's entry line.
- BTU/h
- 9k
- Volts
- 230
- Refrig.
- R-32
- SEER2
- 21
- HSPF2
- 9.2
- Heats to
- 5°F
The maker's photo for this series, not this exact size; the outdoor unit grows with capacity
LG · Single-Zone
LG Mega 12,000 BTU
KNSAC121A / KUSAC121A
~$1,240approximate retailer price at last check, equipment only
- BTU/h
- 12k
- Volts
- 230
- Zones
- 1
- SEER2
- 20
- HSPF2
- 9
- Heats to
- 5°F
- Refrig.
- R-32
- Covers
- 600 ft²
- Wi-Fi
- Built in
Best forMild-to-moderate climates where one 12k head covers a living room or primary bedroom.
Overview
The Mega 12k is LG's volume 1-ton wall unit: 20 SEER2, 9.0 HSPF2 and 12.3 EER2 (AHRI 214931160), 11,000 BTU cooling and 12,000 BTU heating on the retailer's page, and ENERGY STAR certified. Heating works down to 5°F and cooling from 14°F to 118°F. At about $1,240 for the system it sits about $310 above the Standard 12k, which is already in the catalog, and about $920 below the LGRED 12k. A 115V version, KSSAC121B, is sold for $1,259. LG says the 12k covers up to 600 sq ft, a generous figure; 400 to 550 sq ft is the safer assumption in a cold climate. Wi-Fi works through LG ThinQ.
- ENERGY STAR
- 115V version available
- About $920 under the LGRED 12k
Cold-weather output
At 5°F it makes more heat than its 47°F rating (109%), according to the certified NEEP listing for this pairing. LG rates it to keep running down to 5°F.
- COP at 5°F
- 1.77
- Refrigerant
- R-32
- AHRI cert.
- 214931160
- ENERGY STAR cold climate
- Yes
Pairing: KUSAC121A with KNSAC121A. Checked October 8, 2026 on NEEP's ccASHP list; a different head or condenser posts different numbers.
Strengths and catches
Strengths
- +20 SEER2 / 9.0 HSPF2 under AHRI 214931160
- +ENERGY STAR listing
- +115V sibling available
- +Indoor unit 21 to 42 dB
Catches
- −5°F heating limit
- −Cooling and heating ratings sit low for the size at 11,000 / 12,000 BTU
- −$920 below LGRED but with far less cold-weather capability
- −Line set not included
Questions buyers ask
Will a 12k Mega cover my living room?+
LG says up to 600 sq ft, which is generous. The sizing is more realistic at 400 to 550 sq ft in a colder climate. NEEP certifies 12,000 BTU at 47°F.
How does it perform at 5°F?+
NEEP certifies 13,070 BTU at 5°F with a COP of 1.77. That is above its 47°F figure, though the 5°F operating limit means it is at the edge of its range there. It is ENERGY STAR cold climate listed.
Is the Mega 12k a better buy than the Gree Livo 12k?+
The Mega is $1,240 against $1,379 for the Livo, and rates 20 SEER2 and 9.0 HSPF2 against 19 and 8.5. The Livo answers with a 7-year compressor term and heating listed to -13°F. LG's term is 10 years with registration and licensed install.
Does it come in 115V?+
A KSSAC121B 115V version is sold for $1,259. This model is 230V on a 15 to 20 A breaker.
Is the LGRED 12k worth the premium over this?+
The LGRED is $2,162, about $922 more. It buys 25.5 SEER2 and heating rated to -31°F against the Mega's 20 SEER2 and 5°F. In a mild climate the extra cost is hard to recover.
Similar systems
Everything from LGSeries photo
LG · Single-Zone
~$929
LG Standard 18-SEER2 12,000 BTU
Moderate-climate rooms where the goal is the lowest installed price that still comes with a real brand warranty and parts network.
- BTU/h
- 12k
- Volts
- 230
- Refrig.
- R-32
- SEER2
- 18
- HSPF2
- 8.5
- Heats to
- 5°F
Series photoLG · Single-Zone
~$899
LG Standard 9,000 BTU
Mild-climate small rooms where price and a major-brand warranty matter more than winter output.
- BTU/h
- 9k
- Volts
- 230
- Refrig.
- R-32
- SEER2
- 18
- HSPF2
- 8.7
- Heats to
- 5°F