ThermaSol Steam Generator Buying Guide: PRO Series III | Sauna Republic

Steam generator buying guide

Choosing a ThermaSol steam generator starts with your shower's dimensions, because ThermaSol sizes the PRO Series III by volume, steps up for ceilings over 8 feet and makes no adjustment for wall material. Sauna Republic is an authorized ThermaSol dealer.

Quick answer: multiply your shower's length, width and height in feet and choose the smallest PRO Series III whose model number covers the result, since that number is the model's maximum capacity in cubic feet. Add one size for a 9 ft ceiling, and two for a 10 ft ceiling or confirm with ThermaSol. Wall material does not change the size, so a 3 × 4 × 8 ft shower (96 cu ft) takes the PROIII-140 (8 kW), tiled or marble.

The PRO Series III lineup

ThermaSol's current residential steam generator line is the PRO Series III: its January 2026 product list for dealers names seven PRO Series III models and no PRO Series I or II models. The figures below come from the electrical table in ThermaSol's installation manual, which lists every model at 208 to 240 VAC, single phase.

Model	Power	Maximum room size (ceiling up to 8 ft)	Amps	Electrical connection
PROIII-84	6 kW	84 cu ft	28 A	NEMA 6-30P
PROIII-140	8 kW	140 cu ft	37 A	NEMA 6-50P
PROIII-240	10 kW	240 cu ft	46 A	NEMA 6-50P
PROIII-395	11 kW	395 cu ft	55 A	Hardwire
PROIII-575	15 kW	575 cu ft	69 A	Hardwire
PROIII-750	20 kW	750 cu ft	92 A	Hardwire
PROIII-1200	24 kW	1,200 cu ft	110 A	Hardwire

The three smallest models connect with a NEMA plug, and the PROIII-395 and larger are hardwired. With current draw from 28 A to 110 A, have a licensed electrician check your electrical service for the model you choose before you order.

What ThermaSol builds into the PRO Series III

Steam generator sitting level on a stainless drain pan in a closet with copper pipes on top, a typical ThermaSol steam generator location

ThermaSol lists these features on its PRO Series III page; the quoted wording is ThermaSol's.

FastStart. ThermaSol describes "FastStart Technology" as "Steam in seconds, not minutes".

PowerFlush. The generator "includes a self-cleaning PowerFlush system," which ThermaSol lists as exclusive. Its installation manual recommends PowerFlush maintenance every 1,000 minutes of use and asks for a location with easy access for servicing.

Smart Steam. A patented system that ThermaSol says "delivers precise temperature control and steady steam."

Split tank and constant steam. Listed as "Split Tank Technology" and "Constant Steam at a Constant Rate," both marked exclusive.

The MicroTouch control lists "Operates Auto PowerFlush" and "Operates FastStart" among its features.

Size and what comes in the box

ThermaSol's PRO Series III page, which covers all seven models, gives the generator's dimensions as 13 15/16 inches wide, 18 11/16 inches deep and 11 15/16 inches high. Plan the space with at least 6 inches of clearance on all sides and room for the drain pan, which ThermaSol requires on every installation.

The manual's parts list names the generator (with a factory-installed in-line water screen kit), a 3/8 inch hose and fitting, the "Steamhead Housing and Cable Kit (10-8185)", installation instructions, the warranty and a static cling warning label. ThermaSol's product page also lists a stainless steel drain pan and a SteamVection kit as included, and the manual notes that a 50 ft control cable comes with the generator. No control is in the parts list; you choose one separately.

Sizing a ThermaSol steam generator

ThermaSol sizes the PRO Series III on shower volume. Its product page says to "multiply your shower's Length x Width x Height to get the total cubic feet," and its manual says the model number "represents the maximum capacity": the PROIII-240, for example, "will be sufficient up to 240 cubic feet (with a ceiling not exceeding 8 feet in height)." Choose the smallest model at or above your volume, then apply any ceiling step-up.

Wall materials do not change the size

ThermaSol's product page states: "Wall materials do not affect generator size." It does recommend non-porous, moisture-resistant surfaces such as porcelain or ceramic tile, tempered glass and sealed grout, and says natural stone "must be sealed regularly."

Ceiling height

The manual says to "Up-size 1 Unit size for every foot over 8 foot to a maximum of 10 foot." The product page says to size up one generator for a 9 ft ceiling, and for a 10 ft ceiling to size up two or connect with ThermaSol's team to confirm sizing. Beyond that, the manual says: "We do not recommend a ceiling height exceeding 10 feet. Lowering ceiling height to 8 feet helps create a more efficient steam room."

Acrylic walls and modules

ThermaSol's manual says acrylic walls "must be steam rated from their manufacturer" and that "ThermaSol only recommends specific generators for acrylic modules." Confirm the steam rating with the module's manufacturer, and check which PRO Series III models ThermaSol recommends for that module before you order.

Three worked examples

Shower	Volume	How ThermaSol's rule applies	PRO Series III model
3 × 4 × 8 ft, tile walls	96 cu ft	Above the PROIII-84's 84 cu ft, within the PROIII-140's 140 cu ft	PROIII-140, 8 kW
3 × 4 × 8 ft, marble walls	96 cu ft	Wall material does not change the size	PROIII-140, 8 kW
4 × 5 × 9 ft, tile walls	180 cu ft	PROIII-240 by volume, plus one size for the 9 ft ceiling	PROIII-395, 11 kW

Mr. Steam's rules adjust the volume for wall material and ceiling height, so the same showers call for its MS150R (6 kW), MS225R (7.5 kW; 96 + 50% = 144 cu ft with marble walls) and MS400R (9 kW; 180 + 15% = 207 cu ft). Compare the model each brand recommends, not cubic-foot ratings across brands. Our ThermaSol vs Mr. Steam comparison explains both methods, and our Mr. Steam steam generator buying guide covers that line.

Our steam shower generator size calculator runs the numbers for your own shower, and our guide to steam shower generators sets out both brands' sizing rules.

Want the size confirmed before you order?

Send us your shower's length, width, ceiling height and wall material, and we will reply with the PRO Series III model ThermaSol's rules call for and a quote.

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Choosing a ThermaSol control

The control sets the steam session; ThermaSol's FAQ puts it as "Set your temperature and duration using the controller." On each PRO Series III product page, our configurator offers seven ThermaSol controls in three families.

Large touchscreen steam shower control set into a tiled wall at about eye level

Control	Versions and size	What it controls	Finishes	Key features ThermaSol lists
ThermaTouch2	15: 15.875 × 10.0 in. 10: 10.75 × 7.5 in. 7: 8.8 × 6.125 in.	Steam, water, lighting, audio "and more," from a full-color touchscreen	15 on the 15 and 10; black trim only on the 7	Wi-Fi with automatic updates; built-in Bluetooth that pairs with HydroVive; Alexa compatible; two user profiles plus a guest setting
SignaTouch	Wall mount: 5.8 × 4.00 in. Recessed: 6.625 × 3.75 in.	Steam, audio, chromatherapy and lighting	15 on the wall mount; black trim only on the recessed	Configurable touchscreen; two user profiles; Bluetooth when paired with HydroVive, Serenity Advanced or Serenity Essential rainheads; installs vertically or horizontally
MicroTouch	Round, wall mounted: 3 × 3 in. Square, recessed: 3.75 × 3.75 in.	Steam only	15	Capacitive touchscreen; built-in 45-minute timer; recalls the previous steam temperature; integrated temperature sensor; operates Auto PowerFlush and FastStart; brass body

Where the control goes

ThermaSol's ThermaTouch2, SignaTouch and MicroTouch pages carry the same rule: the control "must be installed inside the shower and mounted 60 inches from the floor to the center of the controller." The manual adds that it should be placed "as far as possible away from the steam head and as close as is practical to where the user will be sitting."

Planning the wall and wiring

The ThermaTouch2 needs a wall cutout 3.5 inches deep (7.5 × 5.5 inches for the 7; 10 × 6.625 inches for the 10 and 15) with at least 3.5 inches of clearance around all sides of the mud ring cutout, and its included Power Distribution Module (PDM) requires 110 VAC power. The recessed SignaTouch needs a 5.7 × 3.9 inch cutout at 1 inch depth.

Choosing it in our configurator

After the control, our configurator asks for the steam head, a finish from ThermaSol's 15 applied to both, and in-shower extras such as a fog-free mirror, in-shower Bluetooth speakers, a shower light, a folding seat and essential oils, then sends the build to us for a quote. Our steam shower control and steam head guide compares these controls with Mr. Steam's.

Choosing a ThermaSol steam head

The steam head is where steam enters the shower. Our configurator offers the SteamVection, in round or square, and the No-Touch, which ThermaSol lists as compatible with all PRO Series III steam generators.

Round polished chrome steam head mounted low on a tiled steam shower wall releasing steam

Feature	SteamVection	No-Touch
ThermaSol's description	"Advanced convection technology for even steam distribution," "Whisper-quiet operation" and "Built-in aromatherapy well"	"Patented NoTouch retractable design" and "360° steam dispersion for even coverage"
Shapes and finishes	Round or square, in 15 finishes	Polished chrome
Height	24 inches above the floor or bathtub rim	12 inches above the shower floor
Distance from corners	At least 6 inches	At least 6 inches
Housing	Housing kit included with PRO Series III generators	Steam head housing required (part number A09-5301-2)

ThermaSol's other placement rules:

Away from seating and the control. ThermaSol's SteamVection page says not to install it beneath seating or benches or near the controller, and the manual says to mount the steam head as far as possible from the typical bathing position, seated or standing, and from the in-shower controller.

Sealed and facing up. ThermaSol says the outlet must be sealed so vapor cannot get into the shower walls. The manual says not to use PVC cement, to allow 24 hours for silicone to dry and to mount the steam head facing up so the aroma well can dispense steam.

Oils and heat. ThermaSol's FAQ says essential oils can be used with the SteamVection's integrated reservoir. Its manual says never to fill the reservoir while the unit is on, and not to touch or go near the steam head from the time the unit is on until 1 hour after it shuts off. See our guide to using essential oils in a sauna or steam room.

ThermaSol steam generator installation essentials

These points summarize ThermaSol's installation manual (form 81256 Rev B) and PRO Series III page for planning; they do not replace the manual. ThermaSol requires a licensed electrician for all electrical work, and the manual calls for a qualified licensed plumber for all plumbing, both following national and local codes. Our steam shower installation requirements guide has the full checklist.

Location and access. As near as practical to the shower and up to 50 feet away, in a dry, non-combustible, well-ventilated, finished and climate-controlled space protected from weather, with at least 6 inches of clearance on all sides. Typical locations include a closet, vanity cabinet, climate-controlled attic or basement. Keep the generator upright and level with all connections on top and the access panel unobstructed, never behind walls or inside a bench.

Never. Inside the steam room or outdoors. The manual also keeps both the generator and its plumbing lines out of an unheated attic or anywhere water could freeze.

Electrical. A 208 to 240 V single-phase supply, with each generator on its own separate breaker. Copper wire only, type THHN, with a minimum temperature rating of 90°C; for wire size, the manual refers to the NEC (2002 version).

Water supply. Tee into the existing cold water line, with a brass shut-off valve in an accessible spot in front of the brass union (and the recommended in-line water filter). Copper or brass fittings only: no galvanized fittings and no PEX or PVC tubing. Flush the line into a five-gallon pail before connecting.

Drain pan. Required on every installation, with its 3/4 inch drain connection plumbed to an approved drain. Do not plumb the pressure relief valve into the steam line.

Steam line. 1/2 inch brass pipe or copper tubing (3/4 inch for the PROIII-750 and PROIII-1200), with no valves or traps. Run it up and then down once, or horizontally, never down and then up. Pitch it back toward the generator before any up or down turn and toward the steam room after it, and use steam-rated insulation if the run exceeds 10 feet or passes through cold areas.

Ceiling. A slope of 1 inch per foot; ThermaSol's FAQ says a sloped ceiling helps keep condensation from dripping during a session.

Control cable. 50 feet long, run through electrical conduit as recommended. Do not pinch, nail, staple, wedge or bind it, or wrap it around the steam line.

Flooring and final check. The manual warns that the shower may be a slip-and-fall hazard; ask your contractor or flooring manufacturer whether the flooring is safe to use with steam. In the final pre-check, turn on the water supply and check all connections for leaks.

ThermaSol warranty coverage

ThermaSol's warranty for PRO Series III generators has two stages:

First 2 years: limited in-home warranty. For the original purchaser, ThermaSol will repair or replace, at its discretion, generator parts found to have manufacturing defects and provide the necessary labor. Its warranty page says labor is covered up to a standard, regionally appropriate service rate when a ThermaSol agent or a qualified independent technician does the work.

After 2 years: lifetime factory limited warranty. In the manual's words, "ThermaSol will replace any defective parts for the life of the product and will cover the labor at the factory." The owner is responsible for removal and installation, and for shipping to and from the factory in Round Rock, Texas.

ThermaSol notes that a local service person may not be available for in-home service and that units may require factory service. It requires proof of purchase from an authorized reseller to start any warranty claim.

Homes only

The manual states: "No warranty of any kind, expressed or implied is provided for PROI, PROII, or PROIII Series Generators installed or used in any non-residential setting." ThermaSol's warranty page names hotels, spas, gyms and short-term rentals as examples. For those projects, see our commercial steam generator buying guide.

What the warranty excludes

The manual excludes improper installation that fails to observe national or local plumbing or electrical codes, non-residential or commercial use of a residential unit, service by unauthorized personnel, installation that does not permit proper access for service, modification to any part of the unit and non-ThermaSol repair parts. Failure to install according to ThermaSol's instructions may also invalidate the warranty at its discretion.

Which PRO Series III fits your project

A small tiled shower with an 8 ft ceiling. Choose by volume: up to 84 cu ft, the PROIII-84 (6 kW); over 84 and up to 140 cu ft, the PROIII-140 (8 kW), which covers a 3 × 4 × 8 ft shower (96 cu ft). Both connect with a NEMA plug.

A 9 or 10 ft ceiling. Add one size for a 9 ft ceiling and two for a 10 ft ceiling (or confirm a 10 ft ceiling with ThermaSol), so a 4 × 5 × 9 ft shower (180 cu ft) moves from the PROIII-240 to the hardwired PROIII-395 (11 kW). ThermaSol does not recommend ceilings over 10 ft.

A large shower. The PROIII-575, PROIII-750 and PROIII-1200 cover up to 575, 750 and 1,200 cu ft with an 8 ft ceiling. All three are hardwired (69 A, 92 A and 110 A), and the two largest need a 3/4 inch steam line.

Smart-home and remote control. A ThermaTouch2, which ThermaSol lists with Wi-Fi, Alexa compatibility, Bluetooth that pairs with HydroVive and remote activation of the shower; plan a 110 VAC supply for its PDM. The 15 is ThermaSol's largest control, and the smaller SignaTouch covers steam, audio, chromatherapy and lighting, with Bluetooth when paired with HydroVive, Serenity Advanced or Serenity Essential rainheads.

Steam-only control. A MicroTouch, ThermaSol's steam-only control with a built-in 45-minute timer and temperature recall, round and wall mounted (3 × 3 in) or square and recessed (3.75 × 3.75 in), in 15 finishes.

A hotel, spa, gym or short-term rental. Not a PRO Series III project: ThermaSol provides no warranty for residential generators in non-residential settings.

Frequently asked questions

Which PRO Series III models plug in, and which are hardwired?

ThermaSol's manual lists a NEMA 6-30P connection for the PROIII-84 and NEMA 6-50P for the PROIII-140 and PROIII-240; the PROIII-395 and larger are hardwired. Every model needs a 208 to 240 V single-phase supply on its own breaker, and ThermaSol requires a licensed electrician for all electrical work.

Can a ThermaSol steam generator be used with an acrylic shower?

Only if the acrylic walls are steam rated by their manufacturer, which ThermaSol's manual requires. ThermaSol also recommends only specific generators for acrylic modules, so confirm which model it recommends before you order.

Can a ThermaSol generator go in a vanity cabinet or under a sink?

ThermaSol's manual lists a vanity cabinet among typical locations and below a sink among ideal ones. The space must still be dry, non-combustible and well ventilated, with at least 6 inches of clearance on all sides, an unobstructed access panel and the drain pan in place.

How often does a ThermaSol generator need PowerFlush maintenance?

ThermaSol's installation manual recommends PowerFlush maintenance every 1,000 minutes of use and asks for a generator location with easy access for servicing.

How high should the ThermaSol control and steam head be mounted?

ThermaSol's ThermaTouch2, SignaTouch and MicroTouch controls go inside the shower, 60 inches from the floor to the center of the control. The SteamVection steam head goes 24 inches above the floor and the No-Touch 12 inches, both at least 6 inches from any corner.

What does ThermaSol include with a PRO Series III generator?

The manual's parts list names the generator, a 3/8 inch hose and fitting, the steam head housing and cable kit, installation instructions, the warranty and a static cling warning label, and ThermaSol's product page adds a stainless steel drain pan and a SteamVection kit. The control is chosen separately.

Request pricing on a ThermaSol PRO Series III

Build your generator, control and steam head in the configurator on any PRO Series III product page, or send us your shower's measurements, and we will reply with a quote.

Request pricing

Browse all ThermaSol steam generators to see the seven PRO Series III models.

ThermaSol, Mr. Steam and the product and feature names in this guide are trademarks of their respective owners.

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ThermaSol Steam Generator Buying Guide: PRO Series III Models, Sizing and Installation