Sauna vs steam room
Dry heat at 150–195°F against wet heat at 110–120°F, and what each one costs to build at home. Numbers with their conditions, and the ones we have not measured yet.
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Short answer
Traditional sauna vs Steam room: the numbers side by side
Every row says where its figure comes from. Anything marked manufacturer or retailer is quoted, not measured; the bench runs still owed are listed at the end of the page.
| Attribute | Sauna | Steam room | Condition / source |
|---|---|---|---|
| Air temperature | 150–195°F | 110–120°F | Typical published operating ranges at bench height; steam room at ~100% relative humidity. Not yet measured on our bench. manufacturer |
| Humidity | 10–20% RH dry, 30–40% briefly after water on the stones | ~100% RH, saturated | Published ranges; no hygrometer run of our own yet. manufacturer |
| Heat-up time | 35–55 min to 175°F | 10–20 min to operating temperature | Sauna: Redwood 6-person barrel figures, 8 kW electric heater, ambient not stated. Steam: residential generator maker claims for a tiled 100 cu ft enclosure. manufacturer |
| Electrical | 240V, 30–50A for an electric heater; none for wood-fired | 240V; 40A breaker for a 7.5 kW generator (31 A draw), 50A for 9 kW (38 A draw) | Sauna: circuit size follows heater kW. Steam: Steamist's SMP rating chart (Pub. 230-C) and Mr. Steam MS400R nameplate figures as published by its dealers, September 2026; the Steamist draws 36 A on a 50A breaker if fed 208V. Confirm on the spec sheet before the electrician quotes. manufacturer |
| Enclosure | Wood room, ventilated, no waterproofing | Fully tiled or acrylic, vapor barrier, sloped ceiling, floor drain, sealed door | Construction requirement, not a measurement. Steam enclosures that skip the vapor barrier fail into the wall cavity. code |
| Placement | Indoor or outdoor; outdoor is the common home build | Indoor only, on a drained floor | Construction requirement. code |
| Equipment cost | $5,999–$7,499 for a 4–6 person barrel, plus $969–$1,751 for the heater | $1,645–$3,360 for a 7.5–9 kW generator, plus $700–$1,278 for the control and steam head it needs | Sauna prices from products.json, manufacturer and dealer pages, September 2026. Steam, dealer pages September 2026: Steamist SMP-7 7.5 kW $1,645 at HomeThangs (retail $2,350) and $2,549 at Steam & Sauna Experts; Mr. Steam MS400R 9 kW $3,010 at Steam & Sauna Experts and BiohackerDirect, $3,360 at Cedarbrook. Neither ships with a control or steam head: Mr. Steam TouchTempo control with steam head $700, Basic Butler package (iTempo, steam head, auto-flush, drip pan) $1,278 at Cedarbrook and QualityBath. retailer |
| Installed cost | $8,098–$8,818 wood-fired, $9,247–$11,167 electric, 6-person barrel | About $4,300–$9,000 converting a tiled shower you already have; about $11,000–$16,000 for a new tiled steam room, past $20,000 with stone, glass or a full remodel | Sauna: equipment + pad + circuit or chimney + permit, worked in our home-sauna guide. Steam: generator plus control and steam head at the dealer prices above, plus $1,500–$5,000 for the steam-system install (generator mounting, 240V circuit, water and drain; Art of Steam Co, June 2026), plus $100–$400 permit. Existing-shower figure adds a sealed door and ceiling work at the low end of Fixr's ranges; new-room figure follows Fixr's custom steam shower labor of $3,000–$6,000 and typical total of $8,000–$15,000 (Fixr, January 2025) and Art of Steam's $7,500–$16,000+ for an advanced system. National contractor ranges, not a bid we have received; tiling labor varies most by region. retailer |
| Running cost per session | ≈ 8 kWh, about $1.30 | ≈ 3 kWh, about $0.50 | Arithmetic on nameplate kW (8 kW heater for 60 min; 7.5 kW generator for 25 min) at $0.16/kWh. Heaters cycle after setpoint, so both are upper bounds. Plug-meter run still owed. manufacturer |
| Session length | 10–20 min per round | 10–15 min per round | Manufacturer guidance; see our how-long-in-a-sauna protocol for the sweat-loss measurement that is still owed. manufacturer |
| Maintenance | Restack stones roughly yearly; seal untreated cedar every 2–3 years outdoors | Descale or flush the generator on the maker's schedule; manage grout and mold | Manufacturer maintenance schedules. manufacturer |
Which should you build?
For a home build, the sauna is the simpler install. It can sit outdoors, it tolerates a wood-fired heater that deletes the electrician, and a thermowood shell needs no waterproofing. On cost the split is about the enclosure: converting a shower you already have into a steam room comes in under a barrel sauna, while building a new tiled, sloped-ceiling, drained room to put a generator behind costs more than one. A steam room wins if you specifically want wet heat and have that enclosure, or are renovating a bathroom anyway.
Choose a traditional sauna if
- You have a yard, or any spot a 240V line or a chimney can reach
- You want the higher air temperature and the option of löyly
- You want to avoid tiling, drainage and vapor-barrier work entirely
- You want the larger research base behind the heat you are buying
Choose a steam room if
- You specifically want saturated wet heat and find dry heat unpleasant
- You are already renovating a bathroom with a drain and tiled walls
- You have no outdoor space and no room for a wood cabin indoors
- You want shorter warm-up times and are indoors anyway
What we would buy: traditional sauna
Our sauna pick
Redwood Outdoors Barrel Outdoor Sauna (6-Person)
First-time buyers who want a lifetime-grade shell without stepping up to $10K
The best value in a real, full-size outdoor sauna. Thermowood shell, and a choice of Harvia electric or wood-fired heat that lets you skip the 240V circuit and the electrician bill entirely. Shell, capacity and warranty are Redwood's published figures; we have not weathered one.
- Shell
- Canadian thermowood
- Capacity
- 6 seated / 4 comfortably
- Heat-up time
- 35–45 min to 175°F (electric 8kW)
- Heat type
- Traditional (electric or wood-fired)
- Max temp
- Heater-dependent; not published (mfr)
- Electrical
- 240V / 30–50A by heater; none if wood-fired
- Foundation
- Level gravel or concrete pad
- Warranty
- 5-year structural
What we liked
- Thermowood resists rot and warping far better than untreated cedar
- Wood-fired option means no 240V circuit and no electrician bill
- Assembles in 4–6 hours with two people and no special tools
What we did not
- Barrel shape wastes headroom at the edges of the benches
- Base kit ships with the 6kW KIP; the 8kW that hits the published heat-up time is a paid upgrade
- Needs a level pad; the barrel cradles concentrate load on two points
Harvia M3 Wood-Burning Stove
Rural and suburban yards where running a 240V line is expensive or impossible
Deletes the electrician. At $969 with no 240V circuit, no permit for the circuit and no monthly kWh, wood-fired is the cheapest path to a hot sauna — if you accept the 20 minutes of tending.
- Fuel
- Wood
- Room volume
- ~300–400 cu ft
- Chimney
- Required, sold separately
- Running cost
- Firewood only
What we liked
- No electrical circuit at all — saves $800–2,000 in installation
- Zero running cost beyond firewood
- Heat quality is what every Finnish sauna purist actually wants
What we did not
- Requires a chimney, roof penetration and clearances to combustibles
- 20–30 minutes of active tending per session
- Some HOAs and municipalities restrict outdoor solid-fuel appliances
What we would buy: steam room
Our steam room pick
Mr. Steam MS400R 9 kW Steam Generator
Converting an existing tiled shower, or a new steam room up to about 250 cu ft
The residential steam generator dealers stock most widely, sized for a 162–257 cu ft tiled enclosure. Every figure here is Mr. Steam's nameplate as published by its dealers; we have not metered a session or timed a warm-up. Budget the control and steam head on top, and a 50A circuit.
- Output
- 9 kW, 240V single phase
- Room size
- 162–257 adjusted cu ft
- Draw
- 38 A on a 50A breaker
- Controls
- Sold separately (TouchTempo $700, Basic Butler package $1,278)
- Tank
- Stainless steel, full-port drain valve
- Size
- 14.5 × 6.75 × 14.75 in, 25 lb
What we liked
- Stainless tank, serviceable copper element and a lifetime limited warranty on the unit, per dealer listings
- Mounts up to 25 ft from the enclosure in a closet, vanity or attic, so the bathroom stays quiet
- Assembled in Long Island City, NY, with parts and controls available from the same dealers that sell the heaters
What we did not
- Bare unit: a control and steam head add $700–$1,278 before it runs
- Needs a 240V 50A dedicated circuit, a water line and a drain, plus a fully tiled, vapor-barriered enclosure
- Warm-up, kWh per session and enclosure temperature are all manufacturer claims until we bench it
What we have not measured
The figures above are quoted from makers and dealers unless a row says bench. These are the runs that would replace them:
- Air temperature and relative humidity at bench height in both rooms, logged at one-minute intervals with a K-type thermocouple and a capacitive hygrometer, from cold start to 30 minutes past setpoint.
- Actual energy per session on a plug-in kWh meter for an 8 kW sauna heater and a 7.5 kW steam generator, so the running-cost row stops being nameplate arithmetic.
- Two regional bids for a tiled steam enclosure, so the steam installed-cost cell rests on quotes rather than the national cost-guide ranges it uses today.
Questions buyers actually ask
Is a steam room or sauna better for you?
Neither has been shown to be better than the other. The research base is much larger for traditional saunas, most of it from Finnish cohort studies, but that is a statement about how much has been studied, not about one being superior. Choose on the heat you enjoy and the room you can build.
Which is cheaper to run, a sauna or a steam room?
On nameplate arithmetic a steam room is cheaper per session, roughly 3 kWh against 8 kWh, because the generator runs for 25 minutes rather than an hour. Both numbers are upper bounds; we have not yet metered either. Installation, not running cost, is where the real gap is.
Can you turn a shower into a steam room?
Yes, if the enclosure is fully sealed, tiled or acrylic, with a sloped ceiling, a vapor barrier behind the tile, a drain, and a door that closes tight. The generator sits outside the enclosure within its maker's pipe-run limit. Skipping the vapor barrier is the mistake that puts moisture in the wall.
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Prices captured September 2026 from manufacturer and retailer pages and subject to frequent promotion. See our testing method for how figures are sourced and which ones are still owed.