Our take in 30 seconds
Best for: cold and very cold climatesStrengths
- Keeps 95% of its heat at 5°F, so backup heat rarely runs
- Heating efficiency (HSPF2 11.3) beats 93% of models
- Cooling efficiency up to SEER2 21.5, better than 78% of models
- Variable-speed compressor: quieter, steadier temperatures and better humidity control
Good to know
- Uses R-410A, a refrigerant being phased down; future service may cost more
- Efficiency depends on the indoor unit: SEER2 ranges 18–21.5, so ask which pairing you're quoted
Running-cost calculator
Pre-filled with EIA prices · edit any fieldUses the base certified SEER2 (18) and HSPF2 (11.3). 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 Senville SENA/18HF/OQ at the three ENERGY STAR test temperatures (cooling capacity is 18,000 BTU/h for reference).
Retention at 17°F: 82% · at 5°F: 95%. Learn how to use these numbers in our cold-climate guide.
Estimated running cost in every state
Same unit, very different bills: from about $409 a year in Louisiana to $1,532 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¢ | $151 | $257 | $409 |
| Washington | 14.63¢ | $418 | $51 | $469 |
| Florida | 14.99¢ | $113 | $360 | $473 |
| Mississippi | 14.43¢ | $218 | $260 | $478 |
| Nevada | 12.72¢ | $257 | $229 | $486 |
| Tennessee | 13.42¢ | $316 | $174 | $490 |
| Oregon | 15.92¢ | $428 | $72 | $500 |
| Arizona | 15.05¢ | $177 | $331 | $508 |
| North Carolina | 14.95¢ | $327 | $194 | $521 |
| Kentucky | 13.80¢ | $371 | $152 | $523 |
| Arkansas | 14.37¢ | $314 | $216 | $530 |
| South Carolina | 15.76¢ | $291 | $252 | $544 |
| Utah | 13.31¢ | $425 | $120 | $545 |
| Georgia | 15.90¢ | $294 | $254 | $548 |
| Texas | 15.91¢ | $241 | $318 | $559 |
| Alabama | 16.33¢ | $302 | $261 | $563 |
| Idaho | 13.37¢ | $472 | $94 | $566 |
| Oklahoma | 14.82¢ | $349 | $222 | $571 |
| New Mexico | 16.51¢ | $416 | $165 | $582 |
| Nebraska | 13.54¢ | $478 | $122 | $600 |
| West Virginia | 16.31¢ | $494 | $130 | $624 |
| Missouri | 16.02¢ | $458 | $176 | $634 |
| Kansas | 15.47¢ | $468 | $170 | $638 |
| Virginia | 17.64¢ | $445 | $194 | $639 |
| Wyoming | 14.43¢ | $607 | $72 | $679 |
| Colorado | 17.17¢ | $577 | $120 | $698 |
| North Dakota | 13.31¢ | $649 | $60 | $709 |
| Indiana | 17.02¢ | $572 | $145 | $717 |
| Delaware | 18.70¢ | $535 | $187 | $722 |
| Montana | 15.57¢ | $654 | $70 | $725 |
| South Dakota | 15.15¢ | $637 | $98 | $735 |
| California | 29.75¢ | $450 | $298 | $748 |
| Iowa | 17.06¢ | $660 | $128 | $788 |
| Ohio | 19.38¢ | $652 | $155 | $807 |
| Maryland | 21.40¢ | $612 | $214 | $826 |
| Illinois | 19.32¢ | $682 | $155 | $837 |
| Minnesota | 17.20¢ | $781 | $95 | $875 |
| Pennsylvania | 21.77¢ | $732 | $174 | $906 |
| Wisconsin | 19.41¢ | $816 | $116 | $932 |
| New Jersey | 24.61¢ | $745 | $221 | $966 |
| District of Columbia | 25.98¢ | $699 | $286 | $985 |
| Michigan | 22.99¢ | $928 | $138 | $1,066 |
| Connecticut | 24.51¢ | $907 | $159 | $1,066 |
| Vermont | 23.84¢ | $1,042 | $107 | $1,149 |
| Rhode Island | 28.18¢ | $1,042 | $169 | $1,211 |
| New York | 28.65¢ | $1,060 | $186 | $1,246 |
| Hawaii | 47.18¢ | $40 | $1,227 | $1,266 |
| New Hampshire | 27.64¢ | $1,162 | $138 | $1,300 |
| Massachusetts | 30.48¢ | $1,179 | $183 | $1,362 |
| Alaska | 29.41¢ | $1,484 | $29 | $1,513 |
| Maine | 32.11¢ | $1,404 | $128 | $1,532 |
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 Senville SENA/18HF/OQ at U.S.-average rates.
| Model | Cooling BTU/h | SEER2 | HSPF2 | 5°F kept | Est. yearly cost | |
|---|---|---|---|---|---|---|
| Bryant 37MARAQ18AA3 | 18,000 | 20–23.9 | 13.5 | 71% | $610 (−$78) | Compare |
| Bryant 37MAHAQ18AA3 | 18,000 | 18–21.5 | 12.4 | 90% | $668 (−$20) | Compare |
| Senville SENA-18HF-OG | 18,000 | 18–21.4 | 12.3 | 90% | $672 (−$16) | Compare |
| Fujitsu AOUH18KUAS1 | 18,000 | 18.6–26.3 | 11.4 | 82% | $744 (+$56) | Compare |
| Fujitsu AOUH18LUAS1 | 18,000 | 18.6–23.5 | 11.2 | 95% | $660 (−$28) | Compare |
| Payne 38MARBQ18AA3 | 18,000 | 18–21.5 | 11.3 | 90% | $714 (+$26) | Compare |
Full specifications
| Brand | Senville |
| Outdoor model | SENA/18HF/OQ |
| Certified by | Senville Air Conditioners |
| Product type | Mini-split / multi-split |
| Compressor | Variable-speed (inverter) |
| Refrigerant | R-410A |
| Cooling capacity | 18,000 BTU/h |
| Nominal size | 1.5 tons |
| SEER2 (certified range) | 18 – 21.5 |
| EER2 (best) | 12.5 |
| HSPF2 (best) | 11.3 |
| Heating capacity @ 47°F | 19,000 BTU/h |
| Heating capacity @ 17°F | 15,600 BTU/h |
| Heating capacity @ 5°F | 18,000 BTU/h |
| COP @ 5°F | 1.86 |
| ENERGY STAR cold-climate | Yes |
| Certified indoor pairings | 6 |
| Latest certification | 2026-06 |
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 Senville SENA/18HF/OQ 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 $688 per year ($489 heating, $200 cooling). It ranges from about $409 in Louisiana to $1,532 in Maine.
Does the Senville SENA/18HF/OQ work in cold weather?
Yes. It is ENERGY STAR cold-climate certified and delivers 18,000 BTU/h at 5°F, 95% of its 47°F capacity, with a COP of 1.86 at 5°F.
What size is the Senville SENA/18HF/OQ?
It is rated at 18,000 BTU/h of cooling, roughly 1.5 tons, and 19,000 BTU/h of heating at 47°F. Proper sizing should be confirmed with a Manual J load calculation.