KUSXB421A
LG · HP - Split System
15.2–21BTU/Wh
8.5–10.8BTU/Wh
41000–42000BTU/hr
Yes
LG KUSXB421A: SEER2 21 BTU/Wh, around the middle of the range for air-source heat pumps (category median 20 BTU/Wh).
SEER2: better than 77% of the 574 comparable models within 10% of this capacity. Their median is 16 BTU/Wh.
Where this model sits
The LG KUSXB421A is a 42000 BTU/hr hp - split system using R-32, a refrigerant with moderate global warming potential (GWP 675). At 21 BTU/Wh it ranks around the middle of the 12,218 certified air-source heat pumps models. Among similar-sized air-source heat pumps (within 10% of its size), it is more efficient than the peer median of 16 BTU/Wh.
Specifications
| Efficiency | |
|---|---|
| SEER2 (best combination) | 21BTU/Wh |
| SEER2 (worst combination) | 15.2BTU/Wh |
| HSPF2 (best combination) | 10.8BTU/Wh |
| HSPF2 (worst combination) | 8.5BTU/Wh |
| EER2 (best combination) | 13.2BTU/Wh |
| COP at 5 °F | 1.96 |
| Capacity | |
| Cooling Capacity (max) | 42000BTU/hr |
| Cooling Capacity (min) | 41000BTU/hr |
| Heating at 47 °F | 48000BTU/hr |
| Heating at 17 °F | 31000BTU/hr |
| Heating at 5 °F | 40000BTU/hr |
All 25 specifications
| Configuration | |
|---|---|
| Product Type | HP - Split System |
| Compressor Staging | Continuously variable |
| Cold Climate Certified | Yes |
| Connected Capability | No |
| Series | KUSXB421A |
| Indoor-Unit Combinations Rated | 6 |
| Refrigerant | |
| Type | R-32 |
| GWP Rating | R-32 (GWP:675 | Lower GWP) |
| Identifiers | |
| Model Number | KUSXB421A |
| ENERGY STAR ID | ES_1118034_KUSXB421A_12022024013003_20216445249 |
| Partner | LG Electronics, Inc. |
| Date Certified | 2026-04-22 |
| Available From | 2026-04-15 |
| Markets | United States, Canada |
Documentation
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