Can a mini split heat a home through a cold winter?
Short answer: A mini split can carry most of a cold winter. DIY EasyPro and DIY 5th Gen keep heating down to −13°F outside (DIY Select to −12°F, the DIY 5th Gen 55K multi-zone to −22°F). In most of these states, winter design days stay above −13°F. In Fargo, Bismarck and Great Falls they don’t, and every state in this guide has seen colder nights in the last ten winters, so keep a backup heat source for the coldest nights.
This guide covers Vermont, Nebraska, Rhode Island, Idaho, South Dakota, Montana, Wyoming and North Dakota. Other cold states have their own page: see Mini splits by state.
How cold it gets
| State (city) | Winter design low | Coldest, last 10 winters | Heating hours | Mini split as main heat? |
|---|---|---|---|---|
| Vermont, Burlington | −7.1°F | −20°F | 2,651 | Yes, with backup for the coldest nights |
| Nebraska, Omaha | −2.8°F | −23°F | 2,327 | Yes, with backup for the coldest nights |
| Nebraska, North Platte | −3.7°F | −29°F | 2,403 | Yes, with backup for the coldest nights |
| Rhode Island, Providence | 8.1°F | −9°F | 2,532 | Yes, with backup for the coldest nights |
| Idaho, Boise | 11.4°F | −11°F | 2,532 | Yes, with backup for the coldest nights |
| Idaho, Idaho Falls | −5.5°F | −32°F | 2,590 | Yes, with backup for the coldest nights |
| South Dakota, Sioux Falls | −11.1°F | −27°F | 2,490 | Yes, with backup for the coldest nights |
| South Dakota, Rapid City | −8.4°F | −26°F | 2,434 | Yes, with backup for the coldest nights |
| Montana, Billings | −8.6°F | −26°F | 2,308 | Yes, with backup for the coldest nights |
| Montana, Great Falls | −15.1°F | −37°F | 2,330 | Needs backup heat |
| Wyoming, Cheyenne | −3.1°F | −25°F | 2,658 | Yes, with backup for the coldest nights |
| Wyoming, Casper | −7.9°F | −42°F | 2,620 | Yes, with backup for the coldest nights |
| North Dakota, Fargo | −18.7°F | −33°F | 2,702 | Needs backup heat |
| North Dakota, Bismarck | −17.5°F | −39°F | 2,593 | Needs backup heat |
Winter design low: ASHRAE 2021, 99.6% heating dry bulb. Coldest: NOAA station records, Dec 2016 to Feb 2026. Heating hours: ENERGY STAR heat pump savings calculator (full-load hours; Idaho Falls uses Pocatello).
Which system for cold winters
What size for your room
Measure each room (length × width) and match it to an indoor unit.
| Room size | Indoor unit | Single zone voltage |
|---|---|---|
| Up to 250 sq ft | 6K BTU (multi-zone only) | – |
| 251–400 sq ft | 9K BTU | 115V |
| 401–550 sq ft | 12K BTU | 115V |
| 551–800 sq ft | 18K BTU | 230V |
| 801–1,050 sq ft | 24K BTU | 230V |
| 1,051–1,550 sq ft | 36K BTU | 230V |
Go one size up for rooms with west or south windows, a top floor under the roof, high ceilings, poor insulation, or a kitchen. A garage that isn’t insulated also goes one size up. Full sizing guide
Several rooms? See multi-zone systems
What heating costs to run
Yearly heating cost for one 12K room, if the mini split did all the heating, at each state’s average power price.
| State (city) | Power price | DIY Select | DIY EasyPro | DIY 5th Gen |
|---|---|---|---|---|
| Vermont (Burlington) | 23.8¢ | $1,115 | $1,083 | $998 |
| Nebraska (Omaha) | 13.5¢ | $556 | $540 | $497 |
| Nebraska (North Platte) | 13.5¢ | $574 | $558 | $514 |
| Rhode Island (Providence) | 28.2¢ | $1,259 | $1,223 | $1,127 |
| Idaho (Boise) | 13.4¢ | $597 | $580 | $535 |
| Idaho (Idaho Falls) | 13.4¢ | $611 | $594 | $547 |
| South Dakota (Sioux Falls) | 15.2¢ | $666 | $647 | $596 |
| South Dakota (Rapid City) | 15.2¢ | $651 | $632 | $582 |
| Montana (Billings) | 15.6¢ | $634 | $616 | $567 |
| Montana (Great Falls) | 15.6¢ | $640 | $622 | $573 |
| Wyoming (Cheyenne) | 14.4¢ | $677 | $658 | $606 |
| Wyoming (Casper) | 14.4¢ | $667 | $648 | $597 |
| North Dakota (Fargo) | 13.3¢ | $635 | $617 | $568 |
| North Dakota (Bismarck) | 13.3¢ | $609 | $592 | $545 |
Estimate, not a quote: 12,000 BTU × heating hours ÷ HSPF2 ÷ 1,000 × price. Uses MRCOOL’s cold-climate rating (HSPF2 Region V). Product pages show the standard rating (Region IV), which is higher. Power price: EIA, August 2026. On nights below the heating limit the backup heat runs instead, so the real split depends on your home.
What the equipment costs
Prices for complete single zone systems: outdoor unit, indoor unit, pre-charged line set and remote. Shipping is free to all 8 states in this guide.
| Size | DIY Select | DIY EasyPro | DIY 5th Gen |
|---|---|---|---|
| 9K | $1,249 | $1,487 | $2,329 |
| 12K | $1,399 | $1,599 | $2,359 |
| 18K | $1,690 | $1,806 | $2,909 |
| 24K | $1,899 | $2,109 | $3,329 |
| 36K | – | – | $3,769 |
Rebates by state
Most utility rebates need a participating contractor, so a DIY install usually doesn’t qualify. Rebates checked November 2026. Amounts change; confirm with your utility.
Vermont
| Utility | Up to | Who installs |
|---|---|---|
| Green Mountain Power (income-qualified) | $2,200 | No contractor rule listed, confirm with your utility |
| Efficiency Vermont (income-qualified) | $200 | No contractor rule listed, confirm with your utility |
Nebraska
| Utility | Up to | Who installs |
|---|---|---|
| Lincoln Electric System (City of Lincoln) (income-qualified) | $3,000 | Needs a participating contractor |
| Lincoln Electric System (LES) | $1,000 | Needs a participating contractor |
| Omaha Public Power District | $525 | Needs a participating contractor |
| Nebraska Public Power District | $400 | Needs a participating contractor |
| Southern Public Power District | $400 | Needs a participating contractor |
Rhode Island
| Utility | Up to | Who installs |
|---|---|---|
| Rhode Island Energy | $1,272 | Needs a participating contractor |
Idaho
| Utility | Up to | Who installs |
|---|---|---|
| Idaho Falls | $1,600 | Needs a participating contractor |
| Kootenai Electric Cooperative | $900 | Needs a participating contractor |
| Avista | $600 | Needs a participating contractor |
| Idaho Power | $500 | Needs a participating contractor |
| Rocky Mountain Power | $450 | Needs a participating contractor |
South Dakota
| Utility | Up to | Who installs |
|---|---|---|
| Northern Electric Coop | $600 | No contractor rule listed, confirm with your utility |
| (Heartland Consumers Power District) Sioux Falls, SD | $500 | No contractor rule listed, confirm with your utility |
| Black Hills Energy | $250 | No contractor rule listed, confirm with your utility |
Montana
| Utility | Up to | Who installs |
|---|---|---|
| Yellowstone Valley Electric Cooperative | $783 | No contractor rule listed, confirm with your utility |
| NorthWestern Energy | $450 | No contractor rule listed, confirm with your utility |
Wyoming
| Utility | Up to | Who installs |
|---|---|---|
| Rocky Mountain Power | $1,700 | Needs a participating contractor |
| High West Energy | $1,500 | No contractor rule listed, confirm with your utility |
| (Tri-State) Big Horn REC | $1,500 | No contractor rule listed, confirm with your utility |
North Dakota
| Utility | Up to | Who installs |
|---|---|---|
| Otter Tail Power Co | $1,566 | No contractor rule listed, confirm with your utility |
DIY or a pro
MRCOOL DIY systems are built for a homeowner install: the line set comes pre-charged and connects by hand, so there’s no vacuum pump or refrigerant work. Most people hire an electrician for the new circuit, and permit rules depend on your city. Can you install a mini split yourself?
