Our take in 30 seconds
Best for: mixed climates with occasional hard freezesStrengths
- Heating efficiency (HSPF2 10.5) beats 85% of models
- Cooling efficiency up to SEER2 21.7, better than 79% of models
- Variable-speed compressor: quieter, steadier temperatures and better humidity control
- Uses newer, lower-impact R-32 refrigerant
Good to know
- Efficiency depends on the indoor unit: SEER2 ranges 16.4–21.7, so ask which pairing you're quoted
Running-cost calculator
Pre-filled with EIA prices · edit any fieldUses the base certified SEER2 (16.4) and HSPF2 (10.5). Assumes the unit is correctly sized. How we calculate.
Heating capacity as it gets colder
A heat pump's output falls as outdoor temperature drops. This is the certified heat output of the LG KUSXB121A at the three ENERGY STAR test temperatures (cooling capacity is 12,000 BTU/h for reference).
Retention at 17°F: 66% · at 5°F: 74%. Learn how to use these numbers in our cold-climate guide.
Estimated running cost in every state
Same unit, very different bills: from about $320 a year in Louisiana to $1,318 in Maine, driven by local electricity prices and how much heating or cooling the climate needs. Click a column to sort.
| State | Price | Heating | Cooling | Total / yr |
|---|---|---|---|---|
| Louisiana | 12.87¢ | $132 | $188 | $320 |
| Florida | 14.99¢ | $99 | $263 | $362 |
| Mississippi | 14.43¢ | $190 | $190 | $381 |
| Nevada | 12.72¢ | $224 | $168 | $391 |
| Arizona | 15.05¢ | $155 | $242 | $397 |
| Washington | 14.63¢ | $365 | $37 | $402 |
| Tennessee | 13.42¢ | $276 | $128 | $403 |
| Oregon | 15.92¢ | $374 | $52 | $426 |
| North Carolina | 14.95¢ | $285 | $142 | $427 |
| Arkansas | 14.37¢ | $274 | $158 | $432 |
| Kentucky | 13.80¢ | $324 | $111 | $435 |
| South Carolina | 15.76¢ | $254 | $185 | $439 |
| Georgia | 15.90¢ | $257 | $186 | $443 |
| Texas | 15.91¢ | $210 | $233 | $443 |
| Alabama | 16.33¢ | $263 | $191 | $455 |
| Utah | 13.31¢ | $371 | $88 | $459 |
| Oklahoma | 14.82¢ | $304 | $163 | $467 |
| Idaho | 13.37¢ | $412 | $68 | $480 |
| New Mexico | 16.51¢ | $363 | $121 | $484 |
| Nebraska | 13.54¢ | $417 | $89 | $506 |
| West Virginia | 16.31¢ | $431 | $95 | $526 |
| Missouri | 16.02¢ | $399 | $129 | $528 |
| Virginia | 17.64¢ | $388 | $142 | $530 |
| Kansas | 15.47¢ | $408 | $125 | $533 |
| Wyoming | 14.43¢ | $529 | $53 | $582 |
| Colorado | 17.17¢ | $504 | $88 | $592 |
| Delaware | 18.70¢ | $466 | $137 | $603 |
| Indiana | 17.02¢ | $499 | $106 | $605 |
| North Dakota | 13.31¢ | $566 | $44 | $610 |
| California | 29.75¢ | $393 | $218 | $610 |
| Montana | 15.57¢ | $571 | $51 | $622 |
| South Dakota | 15.15¢ | $556 | $72 | $628 |
| Iowa | 17.06¢ | $575 | $94 | $669 |
| Ohio | 19.38¢ | $568 | $113 | $682 |
| Maryland | 21.40¢ | $534 | $157 | $690 |
| Illinois | 19.32¢ | $595 | $113 | $708 |
| Minnesota | 17.20¢ | $681 | $69 | $750 |
| Pennsylvania | 21.77¢ | $639 | $127 | $766 |
| Wisconsin | 19.41¢ | $712 | $85 | $797 |
| New Jersey | 24.61¢ | $650 | $162 | $812 |
| District of Columbia | 25.98¢ | $610 | $209 | $819 |
| Connecticut | 24.51¢ | $791 | $117 | $907 |
| Michigan | 22.99¢ | $809 | $101 | $910 |
| Hawaii | 47.18¢ | $35 | $898 | $932 |
| Vermont | 23.84¢ | $909 | $78 | $988 |
| Rhode Island | 28.18¢ | $909 | $124 | $1,033 |
| New York | 28.65¢ | $924 | $136 | $1,061 |
| New Hampshire | 27.64¢ | $1,013 | $101 | $1,115 |
| Massachusetts | 30.48¢ | $1,028 | $134 | $1,162 |
| Alaska | 29.41¢ | $1,294 | $22 | $1,316 |
| Maine | 32.11¢ | $1,224 | $94 | $1,318 |
Similar-size alternatives
Other mini-split / multi-split units within ±15% of this model's cooling capacity, sorted by efficiency. Cost difference is versus the LG KUSXB121A at U.S.-average rates.
| Model | Cooling BTU/h | SEER2 | HSPF2 | 5°F kept | Est. yearly cost | |
|---|---|---|---|---|---|---|
| Fujitsu AOUH12KTAP1 | 12,000 | 31.5–31.5 | 13.7 | 106% | $401 (−$172) | Compare |
| Bryant 37MAHAQ12AA3 | 12,000 | 20–25.5 | 11.6 | 96% | $433 (−$139) | Compare |
| Senville SENA-12HF-OG | 12,000 | 20–25.4 | 11.6 | 94% | $433 (−$139) | Compare |
| Mitsubishi Electric PUZ-A12NKA7*** | 12,000 | 21.3–26.9 | 10.9 | 38% | $646 (+$73) | Compare |
| Payne 37MARAQ12AA3 | 12,000 | 19–25.5 | 11 | 74% | $443 (−$129) | Compare |
| Bryant 38MARBQ12AA3 | 12,000 | 19.5–25.5 | 10.7 | 97% | $462 (−$110) | Compare |
Full specifications
| Brand | LG |
| Outdoor model | KUSXB121A |
| Certified by | LG Electronics, Inc. |
| Product type | Mini-split / multi-split |
| Compressor | Variable-speed (inverter) |
| Refrigerant | R-32 |
| Cooling capacity | 12,000 BTU/h |
| Nominal size | 1 ton |
| SEER2 (certified range) | 16.4 – 21.7 |
| EER2 (best) | 13 |
| HSPF2 (best) | 10.5 |
| Heating capacity @ 47°F | 15,400 BTU/h |
| Heating capacity @ 17°F | 10,200 BTU/h |
| Heating capacity @ 5°F | 11,400 BTU/h |
| COP @ 5°F | 2.3 |
| ENERGY STAR cold-climate | Yes |
| Certified indoor pairings | 5 |
| Latest certification | 2026-04 |
Source: ENERGY STAR Certified Heat Pumps (U.S. EPA), retrieved November 7, 2026. Capacities and HSPF2 are the highest values across certified pairings; confirm your exact system's AHRI reference number with your installer.
Frequently asked questions
How much does the LG KUSXB121A cost to run per year?
At the U.S. average residential electricity price of 18.16¢/kWh and typical national heating and cooling hours, we estimate about $572 per year ($426 heating, $146 cooling). It ranges from about $320 in Louisiana to $1,318 in Maine.
Does the LG KUSXB121A work in cold weather?
Yes. It is ENERGY STAR cold-climate certified and delivers 11,400 BTU/h at 5°F, 74% of its 47°F capacity, with a COP of 2.3 at 5°F.
What size is the LG KUSXB121A?
It is rated at 12,000 BTU/h of cooling, roughly 1 ton, and 15,400 BTU/h of heating at 47°F. Proper sizing should be confirmed with a Manual J load calculation.