View Full Version : Help - installing a basement bathroom vent

02-16-2009, 10:55 AM
Good afternoon - I am finishing my basement and now in need of installing a bathroom vent. Because the front of my house is brick, I need to run my bathroom fan vent to the back side of the house. This is approx. 30 feet acroos the width of my ranch house basement.

I know the max I can run insulated flexible tubing is 25ft. So I plan to run 4 inch metal duct 30ft.

My question is if this will work - will the fan have enough power to vent thru 30 feet of duct to the back of my house? Any ideas or recommendations?


02-16-2009, 12:09 PM
Each fan will be different, so you need to read the specifications to determine what will work. Keep in mind also that with that length, the air will cool off and you may have condensation issues...this can accumulate and flow back towards the bathroom, so you may want to try to slope it towards the outside. If you do not seal the seams, it could drip out onto the ceiling along the way.

02-16-2009, 08:15 PM
You could install an remote blower fan. Its mounted elsewhere and the only thing connected to the vent in the bathroom is the duct itself. One appropriately sized would not only solve the venting issue but be much quieter as well. I have one for my smoking room and will be installing one for my basement bath as well. They work quite well.

You could also install an inline booster fan wired to come on with the fan but then you might as well put in the blower fan.

Really though, you could just rent a core drill bit and hammerdrill and drill right through the brick and eliminate the issue right off the bat. Its not really much more difficult than drilling the hole for the duct out the back of the house.

02-17-2009, 05:39 AM
I haven't heard of a remote blower fan below. Where is it mounted? How does the moist air get pulled from the room? Do you have any links to a good brand?

02-17-2009, 05:47 AM
30' is a long run, and the air movement of a typical bath fan will definately be affected.

For starters, have you calculated your needed cfm? Industry minimum calls for about 6 air changes per hour. I shoot for 10. A basement bathroom is a recipe for mold if you don't take care of the air movement.

Sound is an issue. If it is too loud people have a tendency not to use it at all! I like max. 1.0 sones, and the ones at 0.6 are really nice, also in the $300 range!

A duct booster moves the sound away from the local area, and greatly improves the air movement. Fantech is the big gorilla in this market:

02-17-2009, 07:11 AM
Panasonic Remote Blower/Inline Fans (http://www2.panasonic.com/consumer-electronics/shop/Building-Products/Ventilation-Systems/Inline-Fans.list.75114_11002_7000000000000005702)

Essentially the way they work is the same as any other fan. But they are placed elsewhere. You run a duct from the bathroom to the fan, then from the outlet on the fan outside.

I have a Broan 200CFM model in my smoking room but I wasn't pleased with the price vs. CFM aspect. I'll be using a Panasonic in the bathroom. Also, keep in mind that the sones will be reduced in the bathroom because the fan isn't actually there.

02-17-2009, 07:35 AM
If you don't mind the look of the vent cover on the front of your house, then just drill the brick. They have tools for that.