Sauna vs Hot Tub: Cost, Power, Weight and Upkeep, Side by Side

The sauna vs hot tub question usually comes up at the same moment: you've decided to put something warm in the backyard, and the budget could stretch to either. We sell saunas and cold plunges, not hot tubs, so take our perspective for what it is. That's exactly why this comparison sticks to figures you can check: the Department of Energy's hot tub analysis, the safety agencies' temperature limits, and the specifications and manuals of the saunas we sell.

The short answer is that a sauna costs less to keep and asks less of you, and a hot tub gives you something a sauna can't: water to float in. The longer answer is below.

Sauna and hot tub, side by side

Sauna figures are the manufacturer's published specifications for the Golden Designs, Dynamic and Maxxus saunas we sell. Hot tub figures are from the Consumer Product Safety Commission, the Department of Energy and the USGS (water at 8.34 lb per gallon); they describe hot tubs generally, not a particular model.

Running cost: why the hot tub costs more to keep

The difference isn't how much power each draws while you use it. It's when they draw it. A hot tub is a large volume of water held at around 100°F day and night, so it loses heat to the air 24 hours a day and the heater keeps replacing it. That's why the Department of Energy measures hot tub efficiency as standby loss, and why its 2025 analysis put a typical baseline hot tub's first-year operating cost at about $569, falling to about $191 for a high-efficiency model.

A sauna starts cold every time. It uses power while it heats up and while you're in it, and then it's off. You can work out your own cost from the heater's rating:

Sauna figures are upper bounds: they assume the heater runs at full rating for every minute it's on, though a thermostat cycles it off once the room is hot. A 120V/15 A circuit can't deliver more than 1,800 watts, which caps any plug-in cabin at 1.8 kW. "1.5 hours" covers preheat plus a session and is our assumption, not a manufacturer figure. Hot tub figures are DOE's national estimates.

Two honest caveats. First, a very efficient hot tub used lightly can cost less than a big outdoor sauna fired up for long sessions several times a week; compare the $191 and $341 lines above. Second, your electricity rate matters more than either: rates vary several-fold between states, so put your own number in the formula. For infrared specifically, our infrared running-cost guide works through more examples.

Power, weight and what goes underneath

Neither is a plug-and-forget purchase at full size, and they ask for different things on installation day.

If an indoor sauna is an option, the wiring question can disappear altogether: a 1–2 person infrared cabin runs on 120V, though the manuals still require it to have a dedicated 15 amp circuit. Our garage and basement sauna guide covers those circuit rules, and the outdoor sauna guide covers bases and weather.

Upkeep: water chemistry vs a damp cloth

A hot tub is a small body of warm water that people sit in, which is an ideal home for bacteria unless it's managed. CDC's guidance for hot tubs is to keep a minimum of 3 ppm free chlorine or 4 ppm bromine, hold the pH between 7.0 and 7.8, and not exceed the manufacturer's upper limits. That means testing, adding chemicals, cleaning or replacing filters, and periodically draining and refilling.

A sauna has no water system. The infrared manuals ask for a wipe-down with water and a soft, damp cloth and no chemical cleaners inside; a traditional sauna adds nothing more than a ladle of water on the stones while you use it. Outdoor wood weathers over time, so follow the care section of your model's manual.

Heat and safety, briefly

They are different kinds of heat. Hot tub water is limited to 104°F: the Consumer Product Safety Commission's guidance is that it should never go higher, that 100°F is considered safe for healthy adults, and that pregnant women should keep to 100°F because water above 102°F can cause harm early in pregnancy. A traditional sauna runs far hotter air, about 170–190°F on the models we sell, and the Golden Designs manual says not to stay in for more than 40 minutes at a time. An infrared sauna sits between them at 118–132°F.

Whichever you choose, the same advice applies: drink water, keep sessions moderate, and ask your doctor first if you're pregnant or have a heart condition. If you want to know what the research does and doesn't show about regular sauna use, our sauna science guide goes through it study by study.

Which should you choose?

If you're leaning toward a sauna, here's where we'd start: outdoor barrels and cabins, a hybrid that does both kinds of heat, and an indoor infrared cabin if 240V wiring is the sticking point.

Or: a sauna and a cold plunge

Some people who start out comparing a sauna with a hot tub end up with a sauna and a cold plunge instead, alternating hot and cold. Be clear-eyed about it: a cold plunge is a tub of water too, so it needs keeping clean, and models with a chiller use power to hold the temperature. But it's far smaller than a hot tub. Our cold plunges start at $499 for an inflatable tub, and a cedar-clad stainless steel barrel is $3,399; we also sell chillers as separate units. The contrast therapy guide explains how people use the two together.

The warranty, in brief

On the Golden Designs, Dynamic and Maxxus infrared cabins, the written warranty runs 1 to 5 years depending on the part: five years on heating elements and electronics in residential use, one year on the wood structure, parts not labour, for the original purchaser at the original site. Outdoor models carry their own terms, which differ by model, so read the full text on the product page before you choose. It's printed on every one.

Tell us where it would go and how many people will use it, and we'll help you weigh it up, including telling you if a hot tub sounds like the better fit.