A typical home sauna session costs between $0.30 and $1.50 in electricity, and running one four times per week comes to roughly $5 to $25 per month. Infrared models sit at the lower end of that range, while traditional Finnish saunas with larger heaters land closer to the top.
If you're thinking about putting a sauna in your home, the first question isn't usually about health benefits. It's about the electric bill.
That's fair. Nobody wants a wellness habit that costs as much as a second mortgage. The good news is that home saunas are more efficient than most people assume. The less good news is that not all saunas are built the same, and the type you choose determines what you'll pay each month.
Let's break down the actual numbers, the variables that matter, and what you can expect depending on your setup.
The short version first
A typical home sauna session costs between $0.30 and $1.50 in electricity, depending on your local rates, the heater size, and how long you stay in. If you sauna four times per week, that's roughly $5 to $25 per month.
That's less than a streaming subscription for most people. But the upfront efficiency of the sauna itself—how well it holds heat, how fast it heats up, and what kind of heater you use—determines where you land in that range.
What drives the cost: the heater
The heater is the only thing in a sauna that draws meaningful power. Lights, if you have them, are negligible. The heater size is measured in kilowatts (kW). Most home saunas use heaters between 4.5 kW and 9 kW.
Here's how that translates to cost. A 6 kW heater running for 45 minutes uses 4.5 kilowatt-hours (kWh). At the U.S. average electricity rate of about $0.16 per kWh (as of 2025), that's $0.72 per session. At a higher rate like $0.25 per kWh, that same session costs $1.13.
If you upgrade to a 9 kW heater, the cost per session goes up proportionally—about $1.08 at $0.16 per kWh for a 45-minute session.
The counterintuitive part: a larger heater isn't always less efficient. A bigger heater heats the room faster, which means the sauna spends less time running at full draw. If you have a well-insulated sauna, a slightly oversized heater can actually reduce total energy use because you reach temperature faster and the heater cycles on and off less frequently.
Infrared vs. traditional: the real efficiency difference
This is where the numbers shift noticeably.
Traditional Finnish saunas use a heater that heats stones, which then radiate heat into the room. The air temperature typically hits 170°F to 200°F. These saunas take 30 to 60 minutes to reach temperature, depending on the heater size and room volume.
Infrared saunas use ceramic or carbon heaters that emit infrared radiation directly to your body. The air temperature stays lower—usually 120°F to 150°F—but you sweat because the radiation heats your tissue directly.
Infrared saunas are more energy-efficient per session for two reasons. First, the heaters are smaller—typically 1.5 kW to 3 kW for a two-person unit. Second, they heat up faster, usually within 10 to 15 minutes.
A 2 kW infrared sauna running for 40 minutes uses about 1.3 kWh. At $0.16 per kWh, that's $0.21 per session. At $0.25 per kWh, it's $0.33.
Compare that to the traditional sauna at $0.72 to $1.13 per session, and the difference is clear. Over a year of four sessions per week, an infrared sauna might cost you $45 to $70. A traditional sauna would run $150 to $235.
But there's a trade-off. Many men prefer the heat profile and humidity of a traditional sauna. The research on cardiovascular benefits and heat shock protein activation is largely based on traditional sauna temperatures (Laukkanen et al., 2018). Infrared saunas produce similar effects at lower air temperatures, but the direct comparison studies are fewer.
Insulation and construction matter more than you think
The biggest variable in sauna efficiency isn't the heater. It's the box.
A sauna that's poorly insulated loses heat through the walls, ceiling, and door. The heater has to run longer and more frequently to maintain temperature. This is where cheap prefab saunas often fail. They use thin wood, minimal insulation, and single-pane glass doors.
A well-built sauna uses at least 2 inches of rigid foam insulation behind the cedar or hemlock interior. The door should be tempered glass with a low-E coating. The ceiling should be insulated more heavily than the walls because heat rises. Vents should be adjustable and positioned to create airflow without dumping heat.
If you're building or buying, check the R-value of the insulation. R-10 walls and R-15 ceilings are reasonable targets. Below that, you're paying the electric company every session.
The preheat penalty
The single biggest waste of energy in home sauna use is preheating.
Most people turn on the sauna, wait for it to hit temperature, then get in. That preheat time is pure energy consumption with nobody inside. If your sauna takes 45 minutes to heat up, you're paying for 45 minutes of full-power heater operation before you even sit down.
Some newer sauna controllers allow you to set a timer so the sauna is ready when you are. That doesn't reduce the energy used, but it means you're not standing around waiting. If you have a smart plug or a programmable controller, set the sauna to start 30 minutes before your typical session time.
A more aggressive approach: don't fully preheat. Get in when the sauna is at 140°F if you're using a traditional unit. Your body will warm up with the room. This cuts preheat time in half and saves roughly 30% of the energy per session.
Location matters
Outdoor saunas are less efficient than indoor ones. They lose heat through the floor and the exterior walls to cold air. If you live in a climate where winter temperatures drop below freezing, an outdoor sauna will cost more to run than the same sauna installed in a heated basement.
If you're building an outdoor sauna, double the insulation in the floor and use a vapor barrier. Consider a vestibule or changing room. Every time you open the door to the outside, you dump hot air and the heater has to catch up.
Indoor saunas in a conditioned space are the most efficient option. They don't have to fight the outdoor temperature, and they're easier to insulate.
Running costs beyond electricity
Electricity is the main expense, but not the only one.
- Traditional saunas with stone heaters require periodic maintenance. The stones need to be replaced every one to two years. They crack and degrade from thermal cycling. A bag of sauna stones costs $30 to $60.
- Infrared heaters have a lifespan of about 5,000 to 10,000 hours. That's 8 to 15 years of regular use. Replacement panels run $100 to $300 each, depending on the brand.
- Wood-burning saunas exist and are popular in Finland and parts of Canada. They are not energy-efficient in the electrical sense—they use fuel. The cost depends on your local firewood prices. In most places, a wood-fired sauna session costs less than an electric one, but the labor is higher. You have to split wood, build fires, and clean ash. Some men prefer the ritual. Others prefer pushing a button.
What the research says about frequency and cost
The Finnish sauna study we referenced earlier (Laukkanen et al., 2018) found that men who sauna 4 to 7 times per week had a 40% lower risk of cardiovascular mortality than men who sauna once per week. The dose-response relationship was clear: more sessions, better outcomes.
If you're aiming for that frequency, the cost adds up. Seven sessions per week at $0.72 per session is $5.04 per week, or about $262 per year for a traditional sauna. At infrared rates, it's about $1.47 per week, or $76 per year.
That's not nothing. But
Frequently asked questions
How much does it cost to run a home sauna per month?
At four sessions per week, expect to pay roughly $5 to $25 per month depending on your local electricity rate, heater size, and sauna type. A traditional sauna running a 6 kW heater for 45 minutes costs around $0.72 per session at the U.S. average rate of about $0.16 per kWh. An infrared sauna at the same rate costs closer to $0.21 per session.
Are infrared saunas cheaper to run than traditional saunas?
Yes, infrared saunas are more energy-efficient per session because their heaters are smaller and they heat up faster. Over a year of four sessions per week, an infrared sauna might cost $45 to $70 in electricity, while a traditional sauna would run $150 to $235. The trade-off is that many people prefer the heat profile and humidity of a traditional sauna.
Does sauna insulation really affect running costs?
It's actually one of the biggest variables in what you pay. A poorly insulated sauna loses heat through the walls, ceiling, and door, forcing the heater to run longer and more often. Well-built saunas use at least 2 inches of rigid foam insulation, with R-10 walls and R-15 ceilings as reasonable targets. Cheap prefab units with thin walls and minimal insulation will cost you more every session.
Does skipping a full preheat save money on sauna electricity?
Getting into a traditional sauna before it fully reaches temperature, such as at 140°F rather than waiting for peak heat, can cut preheat time in half and save roughly 30% of the energy per session. The preheat period is pure energy consumption with nobody inside, so shortening it is one of the most practical ways to reduce running costs.