A home steam room: what it really takes to build one
What the Kohler, ThermaSol and Mr. Steam manuals ask of the room, the circuit and the plumbing, where they disagree, what the generators list for, and the burn, mold and health warnings to read before you order.
Short answer: A built-in home steam room is a construction job. Mr. Steam’s manual asks for a fully enclosed room with a sloped ceiling, a floor drain and nonslip flooring, installed by licensed electricians and plumbers, and Kohler, ThermaSol and Mr. Steam all want the generator on its own circuit. On Nov. 2, 2026, Mr. Steam’s price sheet started at $2,125.00 for a small package and $3,075.00 for a generator alone. We found no maker that prints a total for the finished room. Read the burn warnings first, ask a clinician if you are pregnant or have heart, blood pressure or circulation problems or diabetes, and keep children supervised.
This guide is general information, not building, electrical or medical advice. Your contractor, electrician, building department and clinician come first.
We did not build, install or test a steam room. Everything here comes from the makers’ manuals, government pages and health sources named, read between Oct. 24 and Nov. 2, 2026. All three makers’ manuals were on their own websites.
Home steam options at a glance
| Built-in steam shower or room | Maker-built freestanding unit | Portable steam sauna | Home sauna instead | |
|---|---|---|---|---|
| What it is | Generator, control and steam head, plus a sealed room built around them | A glass enclosure with its own generator, such as Mr. Steam’s SteamPod | An enclosure with your head outside, joined by tubing to a steam unit | A barrel or cabin with a heater, or an infrared cabin |
| Electrical | Its own circuit, 208V or 240V, wired by an electrician | SteamPod: a standard 20 Amp, 120v wall outlet | Plugs in | Traditional heater: 240 volts. Some infrared cabins: 120 volts |
| Plumbing | Water line, floor drain, drain at the generator | SteamPod: none, you fill a reservoir | A 2-liter or 3-liter steam unit on the recalled models | No water line in Almost Heaven’s barrel manual |
| Who does the work | Licensed trades | Mr. Steam says no contractor needed | You | You or a paid installer |
| Main hazards | Steam head burns, overheating, slipping, mold inside the wall | Steam burns, overheating | Burns: one brand recalled in 2026 | Heater and stone burns, overheating, slipping |
Why the enclosure decides a built-in project
Steam is water in two forms. Schluter, which makes tile waterproofing systems, says steam showers need to manage liquid and vapor to avoid mold growing in wall cavities and wood framing rotting. It also says tiles and grout are not inherently waterproof, so the tile alone does not protect what is behind it.
Mr. Steam’s manual lists what the room needs. It must be completely enclosed, with full walls, door, floor and ceiling. Walls and ceilings need a water-resistant, non-porous surface such as tile, marble or molded acrylic. The ceiling should be sloped to prevent dripping, the room needs a floor drain, and the floor must be nonslip. It recommends a gasketed door.
ThermaSol’s Day Spa manual says the room should be vapor proof, with a door that seals well so the steam does not escape.
So a generator does not turn an ordinary shower into a steam room. Mr. Steam says to use its list in consultation with an architect, designer and contractor.
What three makers’ manuals require, side by side
These are the install documents on each maker’s own website on Nov. 2, 2026. Not printed means we did not find the item in that document. Follow the manual for the exact generator you buy.
| Item | Kohler Invigoration, guide 1230487-2-E | ThermaSol PRO Series, copyright 2016 | Mr. Steam MS series, manual rev. 6.26 |
|---|---|---|---|
| Room size | 5 kW for 84 cubic feet, up to 22 kW for 634 | Length x width x height; PRO-84 for 84, PRO-1000 for 1000 | Length x width x height; MS90R for 0 to 71, MSSUPER3R for 412 to 482 |
| Stone and glass | Not printed; an older Kohler guide rates lower for natural stone | Not printed; its Day Spa manual says wall material is irrelevant | Natural stone, add 50%; acrylic or fiberglass, subtract 40% |
| Ceiling over 8 feet | Next largest generator for every added foot | One unit size up per foot, to a maximum of 10 foot | Add 15% per foot, max 10 feet |
| Ceiling slope | Not printed | 1 inch per foot | Should be sloped; no figure |
| Door | Not printed | Day Spa manual: vapor proof door that seals well | Gasketed door recommended |
| Floor drain in the room | Not printed | Not printed | Provide a floor drain |
| Pan under the generator | Allow for a drain pan | Drain pan required | Drip pan strongly recommended |
| Longest steam pipe | Within 25 feet | Up to 50 feet | Up to 60 feet, insulated |
| Space around the generator | 12 inches on all sides | 6 inches around | 12 inches at both ends and top |
| Circuit | Dedicated; 5 kW needs 240 V, 40 A | Own separate breaker; PRO-84 lists 28 amps, breaker 30 | Separate circuit breaker; MS90R lists 21 amps at 240V |
| Who wires it | Qualified electrician | Licensed electrician | Licensed electricians and plumbers only |
| Steam head height | 6 inches above the floor | 24 inches from the floor or tub rim | 6 to 12 inches above the floor |
| Flushing | Prompts a power clean after 600 minutes | Power Flush every 1000 minutes | Drain every 2 months, more often with hard water |
The makers disagree on stone, as the next section shows. They differ on the ceiling too: ThermaSol prints 1 inch per foot, and Schluter prints 2 inches (50 mm) per foot minimum. And a closet that works for a 60-foot pipe run may not work for a 25-foot one.
Sizing a steam generator: when stone moves you up a model
The first step is the same everywhere: length x width x height in feet gives cubic feet. What happens next depends on the maker.
Mr. Steam makes no adjustment for ceramic or porcelain tile on cement board or a mortar bed. For natural marble, stone, shale, glass block or concrete, it adds 50%. Its chart puts 108 to 161 cubic feet on the 7.5 kW MS225R at 32 amps, and 162 to 257 on the 9 kW MS400R at 38 amps. So any tile room in the first row lands in the second if you finish it in natural stone.
An older Kohler guide works the same way: one of its generators is rated for 125 cubic feet with ceramic tile on sheetrock, 75 with natural stone tile and 65 with natural stone slab. ThermaSol’s Day Spa manual says the opposite, that wall material is irrelevant.
We found no figures on how often home steam rooms are undersized. Size by the method in your own generator’s manual, and have the contractor confirm the finished room’s volume before you order.
What the makers list, and the total we could not find
Mr. Steam is the only one of the three whose list prices we could read. Its pricing page showed this residential sheet under 2026 Pricing on Nov. 2, 2026; the sheet says revised July 15, 2025. Its price book says prices are subject to change without notice.
| Mr. Steam product | What it is | List price |
|---|---|---|
| Steam@Home SAH3000R | Package for 60 to 75 cubic feet: generator, steam head, SteamStart | $2,125.00 |
| MS90R | Generator for 0 to 71 cubic feet | $3,075.00 |
| MS225R | Generator for 108 to 161 cubic feet | $4,075.00 |
| MS400R | Generator for 162 to 257 cubic feet | $4,300.00 |
| TempoTouch | Control, polished chrome | $1,000.00 |
| Aroma Design Finish SteamHead | Steam head, round, polished chrome | $275.00 |
| SteamPod | Freestanding personal steam room | $7,150.00 |
Its manual says MS pricing is for the generator only, without control or steamhead.
We could not read Kohler’s retail page, and ThermaSol’s manual prints no prices. We found no maker that prints a total for a finished steam room, and no official survey of what one costs, so this guide gives no range. Waterproofing, tile, door, drain, wiring and permits come on top. Written quotes for your bathroom are the only numbers that apply.
Wiring and plumbing: why the manuals name licensed trades
ThermaSol requires a licensed electrician for all electrical work and says plumbing shall be done by a qualified licensed plumber. Mr. Steam says all installation and service is for qualified and licensed electricians and plumbers only. Kohler says all electrical work should be done by a qualified electrician.
The manuals explain why the plumbing matters. Kohler warns that a pressure relief valve aimed into the enclosure may spray hot water and burn the user. Mr. Steam warns that blocked steam flow may discharge boiling water through the steam head.
Every built-in generator in these manuals wants its own circuit, so check your panel with the electrician before you buy. Mr. Steam also asks for a power disconnect within sight of the generator, or one that can be locked open. Ask whether your code wants ground-fault protection: an older Kohler guide says not to install a GFCI on that unit, and we did not read the National Electrical Code.
The generator goes outside the room, in a heated space with room to service it. Mr. Steam says a shock hazard will occur if it is inside the steam room.
Permits, fans and local steam shower rules
Rules are local, so call your building department before you order. Three local government handouts show what to ask. They are examples, not your code.
- Permits. Blaine, Minnesota, says various permits may be required based on the scope of work, and lists remodel, plumbing, mechanical and electrical permits separately.
- The fan. Roseville, California, requires an exhaust fan of at least 50 cfm intermittent or 20 cfm continuous in all bathrooms with a tub or shower, ending outdoors.
- Steam showers by name. Woodside, California, says a steam shower shall have an approved vapor barrier, that green board shall not be used as tile backing, and that the steam unit shall be installed per its listing. Its handout prints the ceiling slope in two places: 1 to 2 inches per foot in one, and a minimum of 2 inches per foot in the other.
One point needs settling early. Mr. Steam says no heating, venting or air conditioning devices should be installed inside the steam room, yet a bathroom may need a fan. Ask the inspector where the fan belongs before the ceiling is framed.
Mold behind the tile: what EPA says to watch for
EPA says the key to mold control is moisture control, and that water-damaged areas should be dried within 24 to 48 hours to prevent mold growth. Mold can hide on the back side of dry wall and inside walls around pipes.
EPA says you may suspect hidden mold if a building smells moldy but you cannot see the source. We found no official figure for how long a failed vapor barrier takes to show, so treat that smell as a reason to look.
Mold can matter for health. EPA says it can cause asthma attacks in people with asthma who are allergic to mold, and can irritate the eyes, skin, nose, throat and lungs.
For a moldy area under about 10 square feet, EPA says you can handle the job yourself in most cases. Above that, or after a lot of water damage, it points to its guide for schools and commercial buildings, and it says to consult a health professional first if you have health concerns.
EPA also says to run the bathroom fan or open a window when showering, which is the habit to keep after a steam session too.
Who should check with a clinician before using a steam room
The makers’ own warnings name most of these groups. Ask before your first session if any apply.
- Pregnant or possibly pregnant. Kohler and Mr. Steam say excessive temperatures have a high potential for causing fetal damage during the early months of pregnancy. ACOG says of saunas and hot tubs early in pregnancy that it is best not to. See our pregnancy guide.
- Heart, blood pressure, circulation, diabetes or obesity. Both makers say to consult a physician first. Cleveland Clinic’s sauna page says to avoid a sauna after a recent heart attack or stroke.
- Taking medication. Some medications may induce drowsiness and others may affect heart rate, blood pressure and circulation, the manuals say. Our medication and heat checklist covers the drug groups.
- Over 65, under 16, or epilepsy. Cleveland Clinic lists these for saunas. We found no steam-specific page from a health body that lists them.
- Asthma. Asthma + Lung UK says that for some people, steam can trigger asthma symptoms. See our asthma guide.
ThermaSol’s manual goes further, telling you to get your doctor’s written permission before use. Kohler says not to drink alcohol or take medications or drugs before or during a steambath, because they greatly increase the risk of hyperthermia. If you take a regular medicine, ask your clinician rather than skipping it.
Overheating in a home steam room: limits and when to call 911
Kohler and Mr. Steam both say to limit steam to 10 to 15 minutes until you are certain of your body’s reaction. Mr. Steam adds: start at a low temperature and set a maximum of 10 minutes. Kohler’s control comes preset to 113°F (45°C) for 15 minutes, with a timer of 10 to 20 minutes.
Hyperthermia is why. The manuals list dizziness, lethargy, drowsiness and fainting, and warn of failure to perceive heat and physical inability to exit the steambath. Someone alone may not notice in time, so tell someone you are going in. Almost Heaven’s sauna manual says people with pre-existing health conditions should not bathe on their own.
Mr. Steam’s label says to exit immediately if uncomfortable, dizzy or sleepy. Cleveland Clinic says to drink water before and after a sauna.
MedlinePlus says to call 911 if a person loses consciousness, becomes confused or has seizures, or has a fever over 102°F (38.9°C). Our guide on feeling faint covers what to do first.
Steam head burns: why the manuals keep you away from it
Kohler puts the steam head 6 inches above the floor, Mr. Steam 6 to 12 inches, and ThermaSol’s PRO manual 24 inches from the floor or tub rim. All of those are within a small child’s reach, and low enough to fall against.
ThermaSol’s warning is the blunt one: do not touch or go near the steam head from the time the unit is on, up to one hour after it has shut off. It says severe burns will occur on contact with the steam head or its steam, and that slipping and falling into it will cause serious burns. Kohler and ThermaSol both say not to put it near a seat, and Mr. Steam says to put it where a bather cannot touch it or the steam by accident.
For a minor burn with unbroken skin, MedlinePlus says to run cool water over it for at least 5 to 30 minutes, not ice water. It says to call 911 if the burn is about the size of your palm or larger, is severe, or you aren’t sure how serious it is. Children under age 5 and adults over age 55 have a higher chance of complications and death from severe burns.
Children and home steam rooms
The makers differ. Kohler says closely supervised at all times, and that the generator is not designed to be used by children. ThermaSol says under 16 only if supervised by an adult. Mr. Steam’s current manual says supervise children at all times, while an older manual still on its site says children under the age of 16 should not use the steambath.
Cleveland Clinic’s sauna page says to check with a provider under 16. We found no official minimum age for a home steam room, so the stricter reading is the safer one to plan around. Talk to your child’s doctor first, and consider who can reach the controls and the steam head when no adult is in the room. Our kids and teens guide covers ages.
Hot water, scalds and Legionella at home
Kohler’s warnings tell you to cool off with the shower, so the tap water rules apply too.
CPSC says most tap water scald injuries and deaths are among the elderly and children under five, and urges setting water heaters to 120 degrees Fahrenheit. It says most adults will suffer third-degree burns from 150 degree water in two seconds and 140 degree water in six. Even at 120 degrees, a five minute exposure could cause them.
CDC lists showerheads among the water systems where Legionella can grow, and says breathing in mist is the most common way people get sick. People at increased risk include current or former smokers, people 50 or older, and people with chronic lung disease or a weak immune system.
CDC’s home advice is to flush a showerhead no one has used for a week or more. It says water heater settings of 130°F to 140°F can kill Legionella but raise the risk of burns, so ask your clinician if you are at higher risk, and use thermostatic valves above 120°F. We found no CDC page on home steam generators, so we make no claim about them.
Steam and sauna compared: temperature and humidity
Cleveland Clinic says traditional saunas are typically heated between 150 F and 195 F, with humidity usually under 20%. Harvard Health says a steam sauna is usually set around 120° F, and that these sealed, extremely humid spaces feel much warmer.
The makers’ controls fit that picture. Kohler’s allows 90°F to 125°F (32°C to 52°C), and Mr. Steam’s SteamPod sheet gives a maximum heating space temperature of 120°F.
Cleveland Clinic’s doctor says there is no clear indication that dry or wet heat is better than the other. Saunas do have more research behind them, by a rough count: a PubMed search of titles and abstracts on Nov. 2, 2026 returned 1,133 papers for sauna and 98 for steam room, steam bath or steam shower. That counts papers, not their quality or findings.
Our sauna vs steam room comparison covers how the two differ in use.
Portable steam saunas: the 2026 recall to check first
A portable steam sauna can look like a cheap way to try steam, so check for a recall before you buy or use one.
On May 28, 2026, CPSC announced a recall of about 1,000 Giantex and Costway portable steam saunas. The steam diffuser can be positioned too close to the body, letting hot steam reach the user. Giantex had nine reports of incidents with burns to extremities, and one incident of a second-degree burn.
They were sold online at Amazon and Walmart from January 2023 through December 2025 for between $68 and $100. If you own one, CPSC says to stop using it and contact Giantex for a full refund.
That is one recall of one brand, and we found no official injury count for the category.
A steam room at a gym, bathhouse or spa tests the humid heat with nothing to buy. Our session cost guide and spa day pass prices show what entry costs.
Maker-built steam units with no construction
Mr. Steam’s SteamPod is the one freestanding unit whose maker’s pages we could read. Mr. Steam describes it as a freestanding, full-body steam enclosure that needs no plumbing, no permanent electrical connection and no construction, and it plugs into a standard 20 Amp, 120v wall outlet. The sheet gives 1.5Kw, a fillable water reservoir and a steam outlet temperature of up to 212°F.
It is listed at $7,150.00 in the price table above. We did not read its manual, so check its warnings on overheating and hot steam.
For a prefab unit in acrylic or fiberglass, ask the maker what the generator and steam head need. Mr. Steam says to consult the enclosure’s supplier on where the steam head goes and offers an acrylic shield. ThermaSol says acrylic walls must be steam rated from their manufacturer.
We could not read other prefab makers’ pages, so we give no other prices or circuit figures.
Should you build a home sauna instead?
This is a comparison, not advice. Which heat you prefer is your call.
A barrel sauna skips the water line: Almost Heaven’s barrel manual lists no plumbing connection. It also has a printed price. Almost Heaven listed its 2-person Salem barrel at $4,485.00 on Oct. 29, 2026, with installation starting at $1,400. A steam room has no such printed total, so we cannot say which costs less for your house.
It still needs an electrician for a traditional heater. Almost Heaven says all electrical work needs a licensed electrician, and asks for 240V, a dedicated 30 amp breaker and 10/2 wire. Clearlight’s Premier IS-3 infrared cabin runs on 120 volts and plugs into a 20 amp outlet. Our home cost guide and infrared guide have more.
A sauna built into a room is not free of moisture work. HUUM, a sauna heater maker, says that if the vapor barrier is not airtight, moisture can build up inside the structure, leading to condensation and mold. A sauna has burn hazards too: Almost Heaven warns that the stones and heater surface may burn your skin.
Home steam room running costs and upkeep
Kohler says approximately one gallon of water per 20-minute session, and Mr. Steam’s chart runs from 0.67 gallons on the MS90R to 2.0 on the MSSUPER3R.
We give no electricity figure. We found no maker that prints electricity use per session, and our running cost calculator covers saunas and plunges only.
Upkeep is the part to plan for, and not only in hard water areas. Kohler says calcium scale from hard water can prevent proper operation and may cause premature failure, and that the feedwater should be tested first. Mr. Steam says to drain every 2 months, or more often in hard water areas, a minimum of two to three hours after the control is off so the water has cooled. Kohler’s control prompts a power clean after 600 minutes of use, which may last up to 45 minutes, and says not to enter the room while it runs.
Warranties vary: Kohler’s generator has a three-year limited warranty, Mr. Steam’s MS series a limited lifetime parts warranty, and Steam@Home a limited one-year warranty. We found no published lifespan for a finished steam room.
FAQ: home steam rooms
Can I convert my existing shower into a steam room?
Sometimes, if the room can meet the generator maker’s list. Mr. Steam’s includes a full enclosure with a ceiling, a sloped ceiling, a floor drain and nonslip flooring. A shower with an open top does not meet it. Ask your building department what permits apply.
How much does a home steam room cost to build?
We found no maker that prints a total. On Nov. 2, 2026, Mr. Steam listed generators from $3,075.00 and a small package at $2,125.00, and the sealed room around them is extra. Written quotes for your bathroom are the only numbers that apply.
How much does a home steam room cost to run?
We found no maker that prints electricity use per session, so we give no figure. On water, Kohler says approximately one gallon per 20-minute session. Plan for flushing, and for water treatment if your water is hard.
Do I need a dedicated electrical circuit for a steam generator?
For a built-in generator, yes, in all three manuals we read. Kohler says each generator requires a dedicated circuit, ThermaSol says its own separate breaker, and Mr. Steam says a separate circuit breaker. The exception we found is Mr. Steam’s SteamPod, which plugs into a 20 Amp, 120v wall outlet.
Is a portable steam sauna worth buying first?
Check for a recall first. CPSC recalled about 1,000 Giantex and Costway units in 2026 after burn reports. A steam room at a gym, bathhouse or spa tests whether you like the humid heat with nothing to buy.
How long should a home steam session be?
Kohler and Mr. Steam say to limit use to 10 to 15 minutes until you are certain of your body’s reaction, and Mr. Steam says to start with a maximum of 10. Exit at once if you feel dizzy, sleepy or uncomfortable.
Is a home steam room safe for children?
The makers differ. Kohler says closely supervised at all times, ThermaSol says under 16 only with an adult, and Mr. Steam says supervise children at all times. The steam head sits low and can cause severe burns, so talk to your pediatrician first.
The bottom line on home steam rooms
A built-in steam room is a sealed room with a generator attached. Read your generator’s manual before anyone frames a wall, and size by that maker’s method. Get a licensed electrician and plumber, ask your building department about permits and the fan, and get written quotes, because we found no maker that prints the total.
Before anyone uses it, check the health warnings, keep the steam head away from seats and children, and start with 10 minutes or less. If you only want to find out whether you like steam, try one at a gym, bathhouse or spa, and check for a recall before buying a portable unit.
Related reading on home heat and steam
- Sauna vs steam room: what’s the difference
- Sauna, steam and asthma: what is safe
- Home cold plunge and sauna cost in 2026
- Home infrared saunas compared
- What to do if you feel faint in a sauna or cold plunge
- Sauna, hot tub and cold plunge with kids and teens
- Is a home sensory deprivation tank worth it?
- Is a home reformer worth it?
- Home cold plunge setups compared
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