Steam Shower Sizing Guide Artofsteamco

Steam Shower Sizing Guide.

If you are considering installing a steam shower generator, you need to know the proper size of generator to buy for your application. There are a range of variables that can affect the correct sizing from dimensions to the material of the shower. Below, we will help guide you to choosing the perfect generator for your shower! *Please note that every manufacturer is different and for the most clear estimation, check their website or spec sheets for their own calculations.*

Finding Cubic Footage.

To find your cubic footage, measure length, width, and height. You then multiply those numbers to find your base cubic footage which we will then adjust for other elements. 


Example: 5L x 5W x 8H = 200 Cu. Ft.

Adjusting The Cubic Footage (If Required).

Adjusting cubic footage is important for certain brands such as Mr. Steam as 2 additional elements can effect how well your steam shower works and creates a consistently steamy environment.

Shower Material: As laid out in our other blog "Guidelines To Follow When Building a Steam Shower", natural stone *may* require an adjustment to cubic footage as it may not heat effectively with a smaller generator. This also applies to marble applications. The height of the shower is also an important factor as we will mention below.


*Depending on manufacturer* Natural stone, natural marble, concrete, glass block, or slate showers: multiply Cu. Ft. by 2.0

Thin set ceramic tile, acrylic, or fiberglass: no multiplication needed.

Other material: Contact us and we can get a proper adjustment for you.


Continuing example: Natural stone 200 Cu. Ft. = 200 x 2 = 400 Cu. Ft.

Ceiling Height:

It is recommended to not go above 10ft ceiling height in a steam shower application as the steam can rise and leave the lower part of the shower with an inconsistent temperature. Ideally, 8ft is the sweet spot for steam shower height. Applications of 9ft and 10ft can require additional steam generator power.

For 9 foot ceiling: Multiply by 1.1

For 10 foot ceiling: Multiply by 1.3

With ThermaSol, each additional foot in ceiling height over 8 feet, go up a generator size up to 10 ft.

Continuing example: Since the shower is 5 x 5 x 8, there is no need to multiply to account for additional ceiling height.

Choosing The Right Generator.

Now lets look at examples of what size generator you would need from each manufacturer. Reminder that each manufacturer can have different max cu. ft. ratings. These max ranges can be found in the product description. Remember, ALWAYS round up your cu. ft. to the next size generator. For example If your shower is 150 sq. ft., do not choose the ThermaSol ProIII-140, rather, choose the ThermaSol ProIII-240

Up to 0-170 Cu. Ft. (4-6KW)


ThermaSol ProIII-140 Artofsteamco


Thermasol ProIII-140

View more options


Up to 170-300 Cu. Ft. (7-9KW)




Amerec ak9 steam generator



Amerec AK9

View more options


Up to 300-575 Cu. Ft. (11-14KW)


Kohler 5531-NA artofsteamco


Kohler 5531-NA

View more options


Up to 575+ Cu. Ft. (15KW+)


Mr. Steam MX6EC1X artofsteamco


Mr. Steam MX6EC1X

View more options


By Brand Comparison

For ThermaSol:

Simple Sizing Formula: Shower L x W x H = Cubic Feet

For every foot of ceiling height over 8 ft., choose next size generator.

(up to 10 ft.) All interior wall material is irrelevant.

For example a shower 5x5x8 (200 cu. ft.) would require a ProI/II/III-240, if the ceiling height is 9 feet, a 395 is required, and for a 10 foot ceiling, a 575 is required.

You can also use their sizing calculator and steam shower builder found here.

For Mr. Steam:

Wall material is included in the Mr. Steam calculation. You can use their sizing calculator found here.

For Amerec:

Use their steam shower sizing calculator found here.

For Kohler:

Use their steam sizing calculator found here.



Hopefully this steam shower sizing guide helped you better understand what size of generator your application requires. As always, feel free to reach out with any questions using our "contact us" page.

You can check out our other blogs below to become better informed on your steam shower purchase:

Read more: The Benefits of Steam ShowersHow To Build The Steam Shower of Your DreamsGuidelines To Follow When Building a Steam Shower


Tags: Steam shower sizing chart, sizing tool, sizing calculator