The Fantech rep is in the business of selling fans. While I love their product line and it's the one I prefer to install, for inside a steam shower you'd want a sealed unit with a positive closing damper.

The "sealed" aspect will keep steam vapor from penetrating into the guts of the fan. The closing damper will prevent vapor from being driven into the duct work, where it will cool, condense, and drip back down into the fan housing, or into the shower through the fan's grill.

Don't confuse the little gravity flapping backdraft damper on most fans with a "positive closing" damper.

The positive closing dampers can either be motorized or spring loaded, gasketing can help provide a positive seal.

Thank you. Mongo, yes, that's what the Fantech guy explained (the positive closing damper). I just don't get the reasoning behind all the extra work (and $$) to put a vent fan in there, with a special damper etc. when the purpose of the steam shower is to accumulate steam. So, I'm leaning against a vent fan in the shower, and just one in the main part of the bath. I still have to figure out what the cfu or whatever the measure is for the motor of the fan. Also, new thought: what about one of those tilting transoms above the shower door? Do I need one of those? I'd rather not, so as to keep a clean look, is that ok? I suppose I can just crack the door a bit to let steam out if I have to. Besides, I'm 5'3" and my husband is 5'7". Seems like a tall reach for either one of us.

In a steam shower, when you're done "steaming" all you do is turn the main shower on and the spray of cool water will almost instantly cause the air temp in the shower to drop enough to cause the steam to condense, it clears the air almost immediately.

It can be advantageous to have a vent inside most any shower. But you just don't want the duct work accessible to steam when using the steam function, thus the desire for a positive closing damper.

You could go with a single fantech fan with a couple of vent grills, one with a positive damper in the steam shower itself, the other outside the shower in the main area of the bath. Only turn on the fan when using the shower as a regular shower, or only when done using the steam shower.

In a typical small bath you can run a fan with about 1.1 CFM per sqft of floor space. In larger baths you can size it off of fixtures; 50cfm per "typical" fixture and 100cfm for things that generate more moisture like jetted tubs, steam showers, etc.

When you start getting towards the 200cfm fans, it's best to install more than one vent grill in the ceiling. Pulling that much volume through a single grille can result in turbulent air noise.

If you have a long/twisting duct then more CFMs might be needed due to static losses in the duct.

Your builder would be able to help you with that though.

Spring-loaded and gasketed dampers are about $30-$50 depending on size.

Check your local code before you do anything. In my city it's against code to have a fan in a steam shower.

My vent is in the main part of the room. There's no issue with the steam dissipating immediately after we turn the steam unit off and open the shower door.

Never heard about the code thing? I fit steam showers for a living and unless your shower is absolutly pumping loads of the stuff out then i cant see why you need a fan..... I take it youv'e been ok so far without one?? Has there been any moisture damage in the bathroom? is it a case of to much steam escaping during the shower or after??? The units I sell come with the fan blowing in as so to circulate the steam better an stop it sitting on the roof, meaning the temperature of the cabin is constant throughout. What the previous guy said about spraying cold water with the shower head was an ok idea. If you do just simply have to much steam in the shower then your generator is to great.

hope this helps

Here is a link that might be useful: my showers

Hello Baller69, could you point out the fans you sell please? I'm looking for a fan to circulate the steam as you've mentioned. Thanks in advance.

This is a help forum and nothing is sold her @Juve Hernandez, sales and customer service is elsewhere on the site.

First, check your local code. Some cities (like Palo Alto) recommend an in-shower vent . "Installation of a relief vent is recommended to relieve pressure build-up inside the steam room. The vent should be located under the bench seat in the shower and taken to the exterior of the building using 1” PVC piping if possible." Other cities, like SF mandate one. If there are no code recommendations, you should have a fan directly outside of the steam shower, venting outside (NOT into the attic). In this case, you would need to either leave the door open or have a transom open. Either way, you must provide a way to relieve the steam and pressure created by the shower. Simply turning on the cold water is not an acceptable solution as the steam humudity remains in a highly pressurized environment and will seek relief, usually inside your walls.

I have a steam shower (we moved into our new build last year) and the vent is just outside the shower. Our steam ahower is also my every day shower. It is completely tiled and has a moisture proof surround under the tile. The bain of my existence is trying to kee that room from smelling mildew-y. I hate that i have to keep the door open at all times.