Steam shower installation
Steam shower installation requirements come from the installation manual for your generator and from national and local codes. This guide sets ThermaSol's PRO Series III manual beside Mr. Steam's 2025 manuals for its MS, MS Super and MAX generators, noting the MAX rules where they differ. It is a planning guide, not instructions on how to install a steam shower: both manufacturers call for a licensed electrician and a licensed plumber, working to national and local codes.
Quick answer: before the walls close, plan walls, ceiling and floor suitable for steam, with a sloped ceiling; an accessible generator space that is never inside the steam room, outdoors or anywhere water could freeze; a 208 to 240 V circuit sized for the model; a cold water line with a shut-off valve; a drain; and a steam line with no valves. ThermaSol allows the generator up to 50 feet from the shower, and Mr. Steam's sizing allows up to 60 feet of insulated steam piping.
The enclosure
The steam shower requirements start with the room. ThermaSol's manual says to make sure the "walls, ceiling and floor materials are suitable for use with steam." Mr. Steam's manuals say the steam room must be completely enclosed, with full walls, door, floor and ceiling, and recommend a gasketed door for steam containment.
Still deciding on steam? See our infrared sauna vs steam room comparison.
Ceiling height and slope
ThermaSol's manual calls for a ceiling slope of 1 inch per foot, and its FAQ explains that a sloped ceiling helps keep condensation from dripping during a session. Mr. Steam's MS and MS Super manual says the ceiling should be sloped so condensate does not drip, but gives no amount, and the MAX manual does not mention slope. Agree on the steam shower ceiling slope with your contractor before framing.
On height, ThermaSol does not recommend a ceiling over 10 feet, says lowering it to 8 feet "helps create a more efficient steam room," and sizes up one unit for every foot above 8 feet. Mr. Steam's manuals say to limit the ceiling to 8 feet and add 15 percent to the volume for each foot above 8 feet, to a maximum of 10 feet.
Example: a 4 × 5 ft tiled shower with a 9 ft ceiling holds 180 cubic feet. ThermaSol's rules call for the PROIII-395 (the PROIII-240, plus one size for the 9 ft ceiling); Mr. Steam's call for the MS400R (180 + 15% = 207 cubic feet). Run your numbers in our size calculator; our steam shower generator guide covers both brands' sizing rules.
Where the generator goes
Both manuals say to place the generator as near as practical to the steam room, and both rule out the same places for a steam generator installation: inside the steam room, outdoors, and an unheated attic or anywhere water could freeze; that last rule covers the plumbing lines too. Typical locations are a closet, vanity cabinet, climate-controlled attic or basement for ThermaSol; a closet, vanity cabinet, heated attic or basement for Mr. Steam's MS and MS Super; and a heated attic or basement for MAX.
| Rule | ThermaSol PRO Series III | Mr. Steam MS and MS Super | Mr. Steam MAX |
|---|---|---|---|
| The space | Dry, non-combustible, well ventilated, finished and climate-controlled | Ambient up to 113°F (45°C); away from flammable or corrosive chemicals and high chlorine | Same, in a room with ventilation; never in a vanity, other small enclosed space or under the bench |
| Mounting | Upright and level, connections on top | Upright on a solid, level surface; wall mounting allowed, with supports | Upright on a solid, level surface; never hung on a wall |
| Clearance | 6 in on all sides | 12 in at both ends and on top; zero to combustibles | 18 in on the left, 21 in on top; zero to combustibles |
| Distance | Up to 50 ft from the shower | Up to 60 ft of insulated steam piping; beyond that, consult the factory | Same as MS and MS Super |
ThermaSol says the generator "must remain accessible at all times," never behind walls or inside a bench, and recommends PowerFlush maintenance every 1,000 minutes of use; Mr. Steam's manuals call for opening the manual drain valve every 2 months, or more often in hard water areas. If your room calls for a MAX such as the MX4R, plan a room with ventilation for it.
Planning the generator space?
Send us your shower's dimensions, wall material and ceiling height, and we will reply with the model each brand's rules call for and a quote.
Get PricingElectrical requirements
Steam shower electrical requirements depend on the model's current draw, so choose the generator before the circuit is planned.
ThermaSol PRO Series III
ThermaSol requires a 208 to 240 V single-phase supply, with each generator on its own separate breaker, copper wire only with a minimum temperature rating of 90°C (type THHN), and a licensed electrician for all electrical work. Its manual lists the current draw and connection for each model:
| Model | Power | Amps | Connection |
|---|---|---|---|
| PROIII-84 | 6 kW | 28 A | NEMA 6-30P |
| PROIII-140 | 8 kW | 37 A | NEMA 6-50P |
| PROIII-240 | 10 kW | 46 A | NEMA 6-50P |
| PROIII-395 | 11 kW | 55 A | Hardwire |
| PROIII-575 | 15 kW | 69 A | Hardwire |
| PROIII-750 | 20 kW | 92 A | Hardwire |
| PROIII-1200 | 24 kW | 110 A | Hardwire |
A ThermaTouch2 control also comes with a Power Distribution Module (PDM) that requires 110 VAC power.
Mr. Steam MS, MS Super and MAX
Mr. Steam's MS and MS Super manual says to use a 240 V unit when the supply is greater than 208 V and a 208 V unit for 208 V power, noting that most homes have 240 V single-phase service; 208 V and three-phase generators are available on request. The manuals also call for:
| Model | Series | Power | Amps at 240 V, single phase |
|---|---|---|---|
| MS90R | MS | 5 kW | 21 A |
| MS150R | MS | 6 kW | 25 A |
| MS225R | MS | 7.5 kW | 32 A |
| MS400R | MS | 9 kW | 38 A |
| MSSUPER1R | MS Super | 10 kW | 42 A |
| MSSUPER2R | MS Super | 12 kW | 50 A |
| MSSUPER3R | MS Super | 15 kW | 63 A |
| MX4R | MAX | 20 kW | 84 A |
| MX5R | MAX | 24 kW | 100 A |
| MX6R | MAX | 30 kW | 125 A |
Amps are from Mr. Steam's manuals; have a licensed electrician size the wire from the chart and your local code. Our ThermaSol buying guide and Mr. Steam buying guide cover each line's models.
Water supply
The steam shower plumbing covers the cold water supply, the drain connections and the steam line. Both brands connect the generator to the cold water line through a 3/8 inch connection with a shut-off valve; the pipe materials differ.
Mr. Steam also says to test the water before installation; its recommended feedwater limits include hardness of 8 to 85 ppm and a pH of 8.0 to 11.4.
Drain, drain pan and safety valve
ThermaSol's PRO Series III page lists a stainless steel drain pan as included, and its manual says the pan "must be installed on all generator installations," with its 3/4 inch drain plumbed to an approved drain. The manual also says not to plumb the pressure relief valve into the steam line.
Mr. Steam sells drip pans separately but "strongly recommends the use of a drip pan in the unlikely event of a plumbing leak." The pan has a 3/4 inch fitting and drains by gravity. Mr. Steam's other drain rules:
The steam line
Both manuals guard against condensate collecting at a low point and blocking the steam; Mr. Steam warns that this may discharge boiling water through the steam head, a scalding hazard.
ThermaSol PRO Series III
Mr. Steam
Steam head placement
In new construction, the steam head rough-in fitting goes in before the wall is finished; ThermaSol's manual reminds installers not to forget it.
ThermaSol
Mr. Steam
Control placement and cable
ThermaSol
Mr. Steam
Our steam shower control guide compares the controls. Choose yours in the configurator on each generator's product page before rough-in. Mr. Steam add-ons that wire back to the generator mean opening the wall if you add them later.
Pre-construction checklist
Review this with your contractor before framing; MAX differences are in brackets. For a full brand comparison, see ThermaSol vs Mr. Steam.
| Item | ThermaSol PRO Series III | Mr. Steam [MAX] |
|---|---|---|
| Enclosure | Walls, ceiling and floor suitable for steam; non-porous, moisture-resistant surfaces | Fully enclosed; gasketed door recommended; non-porous, water-resistant surfaces [also heat-resistant]; nonslip floor; floor drain |
| Ceiling | Slope 1 in per foot; not over 10 ft (recommended) | Sloped [no statement]; limit to 8 ft; sizing stops at 10 ft |
| Generator space | Dry, ventilated, climate-controlled, always accessible; 6 in on all sides; up to 50 ft away | Level surface; ambient up to 113°F; 12 in at ends and top [18 in left, 21 in top; ventilated room; no vanity or wall mounting]; up to 60 ft of insulated piping |
| Power | 208 to 240 V, single phase, own breaker; 28 to 110 A | 240 V single phase standard; separate breaker [fuses or breaker]; 21 to 63 A at 240 V [84 to 125 A] |
| Water | Cold line, 3/8 in NPT, shut-off; copper or brass fittings only; no PEX or PVC | Cold line, 3/8 in NPT, shut-off; brass or rigid copper; 15 to 20 psi recommended |
| Drain | Included drain pan required; 3/4 in drain | Drain valve 1/2 in [1 in]; drip pan strongly recommended |
| Steam line | 1/2 in (3/4 in for PROIII-750 and PROIII-1200); no valves or traps | 3/4 in; no valves; pitch 1/4 in per foot; insulation rated 212°F or higher |
| Steam head | 24 in up (No-Touch 12 in); 6 in from corners | 6 to 12 in up; at least 12 in from walls [two or more] |
| Control | Inside the shower, 60 in to center; 50 ft cable | Inside at 4 to 5 ft, or outside with a remote temperature probe in the room; 30 ft cable, 60 ft maximum |
Warranty and installation
ThermaSol's manual says products must be installed in accordance with the installation instructions provided, and that failure to do so may invalidate the warranty at the manufacturer's discretion. Its exclusions include installation that fails to observe national or local plumbing or electrical codes, installation that does not permit proper access for service, service by unauthorized personnel, and use of a residential unit in a non-residential or commercial application, including a hotel. After the 2-year in-home warranty, ThermaSol's lifetime factory limited warranty replaces defective parts and covers labor at the factory, with removal, installation and shipping left to the customer, so access matters for the life of the generator. ThermaSol requires proof of purchase from an authorized reseller to start any warranty process.
Both Mr. Steam manuals say their generators are for residential use only, that commercial or other non-residential use voids the warranty, and that altering or modifying any Mr. Steam product voids it too. The MS and MS Super manual adds that malfunction due to power spikes, lightning, fire, freezing or flooding is not covered. Sauna Republic is an authorized dealer of both brands.
Commercial project? ThermaSol provides no warranty for residential generators used in hotels, spas, gyms or short-term rentals. See our guide to commercial steam rooms by facility type.
Frequently asked questions
Can I install a steam shower generator myself?
Both manuals call for licensed trades: ThermaSol requires a licensed electrician and a qualified licensed plumber, and Mr. Steam says all installation and service are to be performed only by qualified and licensed electricians and plumbers.
How much slope does a steam shower ceiling need?
ThermaSol's manual calls for 1 inch per foot. Mr. Steam's MS and MS Super manual says the ceiling should be sloped but gives no amount, and the MAX manual does not address slope.
Can the generator go in a vanity cabinet?
For ThermaSol and Mr. Steam's MS and MS Super, a vanity cabinet is one of the typical locations their manuals list, as long as it meets each brand's other location rules, including 6 inches of clearance on all sides for ThermaSol and 12 inches at both ends and on top for MS and MS Super. For MS and MS Super, the generator drain should not share an under-sink trap unless the generator is mounted higher than the sink. The MAX manual rules it out.
Can I use PEX for the water supply?
Not with ThermaSol, whose manual rules out PEX and PVC tubing. Mr. Steam calls for brass piping or rigid copper tubing but allows a flexible copper, braided hose, PVC or PEX feed line where local codes permit.
Where does the steam head rough-in fitting go?
In new construction, set it before the wall is finished. ThermaSol's rule is 24 inches from the floor or tub rim and at least 6 inches from any corner (12 inches above the shower floor for the No-Touch); Mr. Steam's is 6 to 12 inches above the floor, or 6 inches above a tub's top edge, and not within 12 inches of a wall.
Is a drain pan required under the generator?
For ThermaSol, yes: a stainless steel drain pan is listed as included, and the manual says it must be installed, with its 3/4 inch drain plumbed to an approved drain. Mr. Steam strongly recommends a drip pan, which it sells separately.
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ThermaSol, Mr. Steam and the product and feature names in this guide are trademarks of their respective owners.
