What It Really Costs to Run a Hot Tub Through a Montana Winter
A well-insulated hot tub in Montana typically costs about $17 to $53 a month in electricity, with January at the high end. The biggest factors are how well the tub holds heat and how cold it gets outside, not how often you soak.
"How much does a hot tub cost to run" is one of the most searched hot tub questions, and in Montana the follow-up is usually "and what about January?" This guide walks through where the power goes, the actual math at Montana electricity rates, what installation costs, and simple ways to keep the bill down.
What Drives a Hot Tub's Power Bill
Most of the electricity a hot tub uses goes to keeping water hot while nobody is in it. Three parts draw power:
Part | Typical draw | When it runs |
Heater | 3 to 6 kW | Whenever water drops below your set temperature |
Circulation pump | About 60 W to 1.5 kW | Several hours a day to filter and move water |
Jet pumps | About 2 kW each | Only while you're using the jets |
What changes the bill the most:
Outdoor temperature. A colder night means more heat lost through the shell, cabinet and cover.
Insulation. A fully insulated cabinet keeps that heat in.
The cover. A lot of heat escapes from the water surface, so a tight, dry cover is one of the best investments you can make.
Set temperature. Dropping 1 to 2°F can cut electricity use by about 10 percent, according to Swim University.
Wind. A tub in an open, windy spot loses heat faster than one tucked against the house or behind a fence.
The Math at Montana Electricity Rates
At NorthWestern Energy's January 2026 residential rate of 15.19 cents per kWh, a modern insulated hot tub runs about $17 a month in summer and $38 to $53 a month in the coldest part of winter (Montana PSC).
The formula is simple: monthly kWh × your rate = monthly cost. Your utility bill shows your exact rate, and co-op members (Missoula Electric, Flathead Electric) will see different numbers.
Scenario | Monthly use | Monthly cost at 15.19¢/kWh |
Modern insulated tub, summer | About 115 kWh | About $17 |
Modern insulated tub, typical January | About 250 kWh | About $38 |
Modern insulated tub, Montana cold snap (our estimate) | About 350 kWh | About $53 |
Older or poorly insulated tub, winter | About 410 kWh | About $62 |
The summer, January and older-tub figures come from 2026 national estimates for a 400-gallon, 240V tub (Voltflow). The cold-snap row is our own estimate for weeks when Missoula sits below 10°F. Across a full year, a modern tub averages about 177 kWh a month, or roughly $320 a year at NorthWestern's rate.
How often you use it matters less than you'd think. By our math, running a 2 kW jet pump for 45 minutes twice a week uses about 13 kWh a month, roughly $2 (jet pump size from Swim University).
Why Insulation and the Cover Matter Most in Montana
In a Montana winter, a well-insulated tub with a good cover can use about 40 percent less power than an older, poorly insulated one, based on Voltflow's January estimates (250 vs. 410 kWh). That gap is where most of your running cost lives.
What to look for when you shop:
Full-foam or high-performance cabinet insulation rated for cold climates. Every American Whirlpool hot tub we sell in the 400 Series, 800 Series and the 982, plus the swim spas, uses the Northern Exposure insulation system, which carries a lifetime insulation warranty. We recommend it to anyone who plans to soak all winter.
A thick, tapered cover with a tight seal. Check the hinge seam and skirt for gaps. A cover that's soaked up water loses much of its insulating value and should be replaced.
A sealed base that keeps cold ground air and critters out of the cabinet.
An efficient circulation pump that runs on low power for long periods instead of firing a big pump often.
For more on construction, insulation and every model, see our American Whirlpool Hot Tub and Swim Spa Buyer's Guide.
What Installation Involves
Running costs are only part of the picture. Most hot tubs need a dedicated 240V circuit, a level base that can carry the weight, and delivery access to your yard.
Electrical. Most American Whirlpool models need a 240V circuit at 30 to 60 amps, depending on the model. The 101, 151 and 160 can be set up for 120V with an optional 15A or 20A GFCI cord, or be hardwired at 240V for faster heating. A licensed electrician runs the circuit and a GFCI disconnect within sight of the tub.
Permit. A new 240V circuit usually needs an electrical permit and inspection. Our step-by-step guide to building permits in Montana explains who handles that for your address.
Base. A filled tub can weigh several thousand pounds. A concrete pad, compacted gravel base or a deck engineered for the load all work. A standard deck usually can't carry it without added support.
Delivery. Measure gates, side yards and tight turns before you buy. We handle delivery and placement, and we'll check access when we visit.
Setup. We fill, start up and balance the water, then walk you through the controls, filters and cover.
On electrical work, we either coordinate a licensed electrician for you or work with the one you hire.
How to Cut Your Running Costs
Keep the cover on and closed tight every time you get out. Replace it when it gets heavy with water.
Add a floating thermal blanket under the cover for extra heat retention in winter.
Block the wind with a fence panel, privacy screen, pergola or landscaping on the windward side.
Drop the temperature 1 to 2°F when you won't use the tub for a few days. Avoid big drops in deep cold, since reheating takes time.
Keep filters clean so the pumps don't work harder than they need to.
Use economy or filter-cycle settings so heating happens when you choose.
Check for drafts around the cabinet and base each fall.
Frequently Asked Questions
Can you use a hot tub outside in a Montana winter? Yes. Hot tubs are built to run year-round, and many owners say winter is the best season to soak. Keep it running, keep the cover on, and don't let it sit unpowered in freezing weather.
Should I drain my hot tub for winter? Most owners shouldn't. A running tub won't freeze. If you won't use it for months, drain and winterize it fully so no water is left in the lines.
Can you install a hot tub in winter? Yes, as long as the ground or pad is ready and delivery access is clear of snow. The tub needs a full fill and heat-up after setup, which takes longer in cold weather.
Is a hot tub worth it? That depends on how you'll use it. At roughly $17 to $53 a month to run in Montana, regular users often find it costs less than a gym or spa membership.
Shop Hot Tubs in Missoula
Big Sky Outdoor Spaces sells, delivers and installs American Whirlpool hot tubs and swim spas, with CleanZone sanitation standard on every tub that can take it. We also offer maintenance plans. Stop by our showroom at 2100 Stephens Ave, Missoula (Monday to Friday 10 to 6, weekends by appointment) or call 406-493-0570.
Running cost estimates are for planning only. Your cost depends on your tub, your rate, your settings and the weather.
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