Best Steam Generator Size for a Walk In Shower
Part of our Home Spa & Outdoor guides.
Steam generators are sized by the room's volume. This page covers showers of 150-350 cubic feet.
Worked example
A 5x4-foot walk-in with an 8-foot ceiling is 160 cubic feet, and a 6x5 is 240. The 9 kW unit's 212-318 cubic foot range fits most walk-ins; go 12 kW for tiled rooms at the top of the range.
Adjustments
- Tile, stone or marble walls: size up one step.
- Ceilings above 8 ft: size up.
- Exterior wall or large glass: size up.
- Acrylic or fiberglass enclosure: listed size is usually fine.
Requirements
A vapor-tight enclosure to the ceiling, a sloped ceiling to stop drips, a dedicated 240 V circuit, a cold-water line and a drain. Use the calculator to check your numbers.
Example calculation
A 5x4 walk-in with an 8-foot ceiling: 160 cubic feet. A 6x5 at 8 feet: 240 cubic feet. Both fit VEVOR's 9 kW range (212-318 cubic feet) once you factor in tile. A 6x5 with stone walls (2x factor, 480 effective) needs a 12-15 kW unit.
Ceiling height matters
A 9-foot ceiling adds 12.5% volume over an 8-foot ceiling. Many walk-ins have a lowered steam ceiling installed to reduce volume; it also makes the steam feel more enveloping.
Door and glass
Walk-in showers often have open entries or partial glass panels. For steam, the enclosure must be fully closed, including above the door. Consider a hinged door with full seals and a top transom.
Control placement
Mount the controller inside the shower at seated height, away from direct spray, and the steam head low and away from the bench.
Frequently asked questions
What happens if the generator is too small?
The room never fills with steam and the unit runs continuously; it's the most common steam shower complaint.
Is a bigger generator always better?
Within reason, slightly oversizing heats faster; but it needs a bigger breaker and wire.
How big is a typical walk-in shower?
Common sizes are 48x36 to 72x36 inches; volume depends on ceiling height.
Do I need a door for steam?
Yes, a vapor-tight door is required.
Where should the steam head go?
Low on the wall, away from seating and feet.
Can I use the same shower for normal showers?
Yes; steam showers work as regular showers too.