Commercial Steam Room Design Guide for Contractors

Commercial steam room jobs are among the most profitable and technically demanding installs a plumbing contractor can take on. The rough-in requirements are more complex than residential, the stakes for getting it wrong are higher, and the client — whether a hotel, spa, or health club — expects it to run flawlessly every day. This guide covers everything you need to spec, install, and maintain a commercial steam room correctly the first time.

PlumbersCrib.com is an authorized dealer of ThermaSol, Mr. Steam, and Amerec. Browse our full commercial steam generator collection or contact our team for help speccing the right system for your project.

How commercial steam rooms differ from residential

The core technology is the same — an electric steam generator heats water to boiling point and pumps steam into a sealed room. But commercial installations differ from residential in ways that affect every phase of the job:

• Higher capacity generators — commercial rooms are larger and serve more simultaneous users, requiring generators built for continuous daily operation rather than short residential sessions
• Continuous duty cycles — a residential generator runs 20–30 minutes once or twice a day. A hotel or health club steam room may run 8–12 hours continuously. The generator, plumbing, and electrical must all be sized and specified for this load
• More demanding maintenance — daily heavy use means more mineral scale buildup, more wear on heating elements, and a greater need for automated cleaning systems and field-serviceable components
• ADA compliance — commercial steam rooms open to the public must meet Americans with Disabilities Act requirements
• Three-phase power — most commercial buildings have three-phase power available, which commercial generators are designed to use
• Professional design coordination — you will be working alongside architects, GCs, MEP engineers, and interior designers. Get the spec locked in early and confirmed in writing before walls close

Sizing a commercial steam room generator

Commercial steam rooms are sized the same way as residential — cubic footage of the room (length × width × height). The differences are the ceiling height, wall materials, door gaps, and the need for a capacity buffer for continuous commercial load. Always size up from the calculated cubic footage on a commercial job.

Commercial generator options: ThermaSol, Amerec, and Mr. Steam

PlumbersCrib.com carries commercial-grade steam generators from three brands. Each covers different capacity ranges and suits different types of commercial projects.

ThermaSol PowerPak Series III

The ThermaSol PowerPak Series III is ThermaSol's commercial generator, designed for health clubs, resorts, spas, and high-use commercial environments. Two models available:

• PP18SR — 18kW — for commercial steam rooms up to 1,000 cubic feet. Available in 208/240V and 480V three-phase
• PP24LR — 24kW — for commercial steam rooms greater than 1,000 cubic feet. Available in 208/240V and 480V three-phase

Delivered fully assembled. Features industrial-grade stainless steel tank, Incoloy heating elements, split tank design, PowerFlush automated inner-tank cleaning, CAN Bus digital communication, and front and top panel access for field servicing. Installs up to 50 feet from the steam room. No separate drain line required — uses the steam room's existing drain. Dimensions: 19"L × 18"W × 32"H. 18-month parts and labor commercial warranty. Browse the commercial steam generator collection.

Amerec AK Series — gangable for commercial capacity

The Amerec AK Series can be ganged in configurations of up to three units to cover rooms up to 1,500 cubic feet. The largest configuration — the AK36 (two 11kW units + one 14kW unit, totaling 36kW) — covers rooms from 1,200 to 1,500 cubic feet. One control required regardless of how many generators are ganged. Each generator requires its own ComfortFlo steamhead. Connection cables sold separately. Sequential Temperature Control, stainless steel tanks, removable heating elements. UL, CSA, and CE listed. Available in 240V or 208V, field-wireable for single-phase or three-phase. Browse the full Amerec lineup.

Mr. Steam CX Series commercial generators

Mr. Steam's CX Series generators are purpose-built for continuous commercial use in health clubs, spas, hotels, and resorts. The CX is an atmospheric generator — quieter than pressurized systems — with a built-in internal temperature shutoff, integral high water cutoff, and a programmed preheat function that brings the steam room to temperature at the start of each day. Factory installed with the Digital 1 Control for easy 24/7 scheduling and AutoFlush operation. Mr. Steam CX systems are installed at Canyon Ranch, The Ritz-Carlton, Bellagio, MGM Grand, and facilities across the US. Browse the Mr. Steam collection.

Room construction requirements

Waterproof substrate. All surfaces behind tile must use a waterproof membrane or cement board — no standard drywall anywhere in the steam room. Steam penetrates standard drywall and causes mold and structural damage. Confirm with the GC and tile sub before walls close.

Ceiling slope. The ceiling must slope a minimum of 2 inches per foot toward one wall to drain condensation. This is the most commonly missed spec detail on commercial steam jobs and a guaranteed callback if it is wrong. Confirm slope with the framing crew before substrate goes up.

Wall and floor materials. Non-porous tile (porcelain or ceramic) is the most practical choice for commercial use — easy to disinfect, resists mold, and does not require a material sizing adjustment for any generator brand. Natural stone is used in luxury spa environments but is porous, requires sealing and more aggressive cleaning, and requires larger generators for Mr. Steam and Amerec installations due to their material multiplier.

Door seals. Glass doors with proper seals are the commercial standard. Even small gaps at the door significantly reduce efficiency and make it harder for the generator to maintain temperature. Confirm door seal spec with the glazier before installation.

Bench construction. Tile-covered concrete benches are the most durable choice for commercial use — hold up to daily heavy use, easy to disinfect, and do not absorb moisture or odors. Wood benches are not appropriate for steam rooms.

ADA compliance

Commercial steam rooms open to the public must meet ADA requirements. Key specs:

• Door clearance — minimum 32" clear opening width (36" preferred), level or ramped entry, no threshold steps
• Turning radius — 60" diameter clear turning space inside the steam room
• Bench height — at least one bench section at 17"–19" from the floor with clear floor space alongside it
• Control placement — 15"–48" from the floor, operable with no more than 5 lbs of force
• Slip resistance — floor surfaces must meet ADA slip resistance standards

Always confirm ADA requirements with the architect and local building authority before finalizing the design.

Plumbing rough-in requirements

Every connection must be confirmed and roughed in before walls close:

• Cold water supply — 3/8" with a proper shutoff valve. No saddle valves — a proper tee fitting is required. Install a PRV set to 15–25 PSI. Use threaded unions for serviceability
• Steam line — 1/2" copper or brass only. No PEX or PVC on steam lines. Slope continuously to avoid condensation traps. Insulate all runs over 20 feet. Do not create horizontal runs that will trap condensate
• Drain line — 3/4" copper sloped to a gravity drain. The ThermaSol PowerPak does not require a separate generator drain — it uses the steam room's existing drain. Amerec and Mr. Steam CX require a dedicated generator drain
• Pressure relief valve — 3/4" copper, required on all generators. Terminate per local and national plumbing codes
• Floor drain — inside the steam room, sized for continuous steam output over a full commercial operating day. Must be accessible and cleanable

Electrical requirements

All commercial generator wiring by a licensed electrician per NEC and local codes. Key specs:

• Dedicated circuit for each generator — sized to the generator's amperage. No sharing with other loads
• Three-phase power — ThermaSol PowerPak and Amerec AK are available in 208/240V and 480V three-phase. Confirm available power configuration with the electrician before ordering
• Circuit breaker — a separate circuit breaker between the power supply and the generator is required, within sight of the unit or lockable in the open position
• No GFI required on the generator circuit
• Control wiring — run in dedicated 3/4" non-metallic conduit. Do not route with power lines. Confirm conduit route before walls close

Ventilation

Do not run an active exhaust fan during steam sessions — it pulls steam out of the room and defeats the system. A timer-controlled exhaust fan that activates after the session ends is the correct approach. The generator room requires its own ventilation per manufacturer specifications. Coordinate with the mechanical engineer on commercial projects — HVAC design for a steam room is a specialized scope.

Hard water and long-term maintenance

Mineral scale buildup is the leading cause of steam generator failure — and the risk is significantly higher in commercial environments where generators run continuously for hours every day. Spec these at rough-in:

• Automated flush system — non-negotiable on a commercial job. ThermaSol PowerPak Series III includes PowerFlush built in. Amerec generators pair with the ADK Auto Drain. Mr. Steam CX includes AutoFlush functionality via the Digital 1 Control. Far easier to install during rough-in than after tile is up
• Water treatment — in hard water areas, a commercial water softener upstream of the generator significantly extends generator life and reduces maintenance frequency
• Removable heating elements — both the Amerec AK Series and ThermaSol PowerPak Series III have field-removable heating elements that can be serviced without pulling the generator
• Drip pan — required under every generator installation

Safety signage requirements

All commercial steam rooms require safety signage posted at or near the entrance. Standard required notices include maximum session length, minimum age, warnings for persons who are pregnant or have cardiovascular conditions, warnings against alcohol or medication use before steam bathing, hydration instructions, and emergency exit information. Confirm signage requirements with the client's local health department and legal counsel before opening — requirements vary by jurisdiction.

Frequently asked questions

What generator do I spec for a hotel steam room?
Calculate cubic footage then add a 25–30% commercial buffer. For rooms up to 1,000 cubic feet, start with the ThermaSol PowerPak PP18SR (18kW). For rooms over 1,000 cubic feet, the PP24LR (24kW) or Amerec AK ganged to 36kW covers up to 1,500 cubic feet. Contact us for a complimentary commercial sizing consultation before you quote.

Does a commercial steam room require three-phase power?
Not necessarily — ThermaSol PowerPak and Amerec AK are both available in single-phase (208/240V) and three-phase (208/240V or 480V). Most commercial buildings have three-phase available and it is more efficient for high-kW generators. Confirm with the electrician before ordering.

Can I use PEX for the steam line on a commercial job?
No — copper or brass only for steam lines on any installation, residential or commercial. PEX and PVC are not acceptable for steam lines.

Does the ThermaSol PowerPak need a separate drain line?
No — the PowerPak uses the steam room's existing drain. No additional drain line is required. Amerec and Mr. Steam CX generators require a dedicated drain connection at the generator location.

What is the warranty on the ThermaSol PowerPak Series III?
18 months parts and labor — this is a commercial warranty, separate from ThermaSol's residential lifetime warranty which applies to the PRO Series III only. The commercial warranty applies specifically to the PowerPak Series III when installed in a commercial environment.

How many steamheads does a ganged Amerec system require?
Each Amerec generator in a ganged configuration requires its own ComfortFlo steamhead — connection cables are sold separately. One control is required regardless of how many generators are ganged.

Shop commercial steam generators at PlumbersCrib.com

• ThermaSol PowerPak Series III — 18kW and 24kW commercial generators
• Amerec AK Series — gangable up to 36kW for rooms up to 1,500 cubic feet
• Mr. Steam CX Series — atmospheric commercial generators for continuous use
• Full commercial steam generator collection — all brands and accessories

Questions about speccing the right commercial system for your project? Contact our team or call 877-881-5501 — we will help you spec it right the first time.