The room sets the size of a steam shower generator. So settle the room first. Measure it. Note what the walls are made of and how tall the ceiling is. Count any outside walls, and any window or skylight. Then fit the generator to that room, along with where it sits and how it’s powered.
The order matters. A generator picked before the room is settled may turn out too small once the wall material, ceiling height and outside walls are counted. Its place and its power can be hard to add after the walls and tile are done. That’s a planning problem, not a product problem.
What Does a Steam Shower Generator Do?
A steam shower pairs an enclosed shower with a steam generator. The generator is a separate appliance that boils water. A water line runs to it, and a steam line carries the steam from it into the shower. A maker’s installation article lists those two connections.
Because the generator is its own appliance, it needs its own place and its own power. That’s why it gets planned alongside the room, rather than picked off a shelf at the end.
How any one model is sized, placed and powered is set by its maker’s instructions. There isn’t one universal chart. So every figure here comes from a maker’s own page, attributed to that maker, and another maker’s page may say something different.
How Is a Steam Shower Generator Sized?
The room comes first. Multiply its length by its width by its height, in feet. That gives you cubic feet. Then adjust that figure for the wall material, the outside walls and the ceiling height. Pick a generator equal to or greater than the adjusted figure.
Those steps come from one steam shower maker’s sizing guide, which publishes the multipliers and the sizes they point to.
- 7.5 kilowatt covers 101 to 250 adjusted cubic feet.
- 10 kilowatt covers 251 to 450.
- 12 kilowatt covers 451 to 550.
- 15 kilowatt covers 551 to 675.
Take that maker’s own example. A room five feet by six feet by eight feet is 240 cubic feet. With marble walls, the chart multiplies by 2.0. That’s 480. With one outside wall, it multiplies by 1.1. That’s 528. The figure lands in the 451 to 550 range, and that maker’s example selects its 12 kilowatt generator.
Keep the same room. Swap marble for ceramic or porcelain tile, and drop the outside wall. Then 240 times 1.35 is 324. That falls in the 251 to 450 range, which is the 10 kilowatt size on the same chart. That second figure is simple arithmetic on the first maker’s chart, not a recommendation. The wall material alone moved the answer by one size.
Other makers publish their own charts, and the figures can differ. So use the chart and the manual for the model that’s actually planned.
What in the Room Changes the Generator Size?
Four things in the room move the number in the first maker’s chart. Each one is a multiplier applied to the cubic feet you measured.
- Wall material. Natural stone or marble multiplies by 2.0. Ceramic or porcelain tile, or glass block, multiplies by 1.35. For any other material, the first maker says to ask it.
- Outside walls. One multiplies by 1.1. Two multiply by 1.2.
- Ceiling height. Nine feet multiplies by 1.15, and ten feet by 1.3. The first maker puts the limit at eight feet for performance, with ten feet the maximum.
- A skylight or outside window. Select the next larger generator. The window or skylight has to be double-pane and sealed from the inside of the steam shower.
A second maker’s installation article also starts with the room. It says to design for comfort, then adjust the steam generator to fit that space. It puts the minimum size comfortable for one person at three feet by three feet by seven feet. It calls an eight-foot ceiling optimal because steam rises. A taller ceiling, up to ten feet, means bumping the generator up in size.
That same maker doesn’t think a sloped ceiling is necessary unless you’ll run sessions more than 45 minutes at a time. It also says to pick non-porous wall materials such as tile and marble rather than porous ones, and that porous materials need a larger generator.
Where Does the Generator Go, and What Does It Need?
The second maker says the generator can sit in a heated attic space, in a closet, or even under a built-in shower bench. One condition comes with that. It can’t be exposed to the inside of the steam space.
The water line and the steam line come with a pipe rule from that maker: brass or copper only, with no PVC and no PEX. It also says you’ll need 240 volt power, or 208 volt, on a dedicated circuit breaker. The first maker states its own voltage rule. The generator’s voltage has to match the home’s service, either 208 or 240 volt.
What a given home can take is a question for the electrician, the plumber and the local building department. The model’s own manual matters too.
Guthrie’s post on whether a heated bathroom floor is worth it names a dedicated circuit among the things that decide whether that upgrade makes sense, so the same early question applies to a steam generator.
Questions to Settle Before the Walls Close
Bring these to the design team early, before the plan is locked.
- How big is the room in cubic feet, and what are its walls made of?
- How tall is the ceiling, and are there outside walls, a window or a skylight?
- Where will the generator sit, and does the plan keep it out of the steam space?
- How will it be powered, and on which circuit?
- Which maker’s chart and manual will the chosen model follow?
Guthrie’s post on the order a bathroom remodel follows puts the layout, the plumbing plan and every finish choice before anyone opens a wall, and that’s where these questions fit.
Frequently Asked Questions About Steam Shower Generators
What is a steam shower?
It’s an enclosed shower paired with a steam generator. The generator boils water, and a steam line carries the steam into the shower. The makers size and place that generator from the room’s own numbers: its cubic feet, its wall material, its ceiling height and whether it has an outside wall or window. The shower and the generator get planned together.
Can an existing shower become a steam shower?
The second maker’s installation article covers both routes: converting an existing shower, and building one from scratch. Either way, the room-first questions don’t change. You still need the room’s cubic feet, its wall material and its ceiling height before a generator size means anything. Whether a particular bathroom can take one is a question for the design team.
Where can a steam generator go?
The second maker lists a heated attic space, a closet, or even under a built-in shower bench. The condition it gives is that the generator must not be exposed to the inside of the steam space. The model’s own manual sets how far it can sit from the shower, so that’s a manual question. Ask your installer before the spot is locked in.
Does a steam shower generator need its own circuit?
The second maker calls for 240 volt power, or 208 volt, on a dedicated circuit breaker. The first maker says the generator’s voltage must match the home’s service, 208 or 240 volt. Those are the makers’ own statements, not a code citation. What a given house can carry is an electrician and local-code question, and that’s the answer that governs.
Will Guthrie help me plan a steam shower?
Guthrie’s experienced design team helps you get the most out of your bathroom layout, and the showroom lets you see materials in person. You can visit the Pleasant View showroom, or schedule a consultation to get started. It’s worth bringing the room’s measurements and your questions about the generator along.
Bring Your Steam Shower Plan to the Showroom
At Guthrie’s Pleasant View showroom, you can see materials in person, from cabinetry and countertops to plumbing fixtures.
So what size steam shower generator does your room need? That depends on the room’s own numbers. Gather them early, with your design team, and the generator gets fitted to the room instead of the other way around.
When the plan is ready for bathroom remodeling, you can visit the Pleasant View showroom or schedule a consultation to get started.
When you’ve got the room’s numbers, talk with Guthrie’s design team about your steam shower plan.
