# brand new bathroom



## dan897857 (Jan 16, 2012)

I just redid my bathroom. The exhaust fan is new and a good model but doesn't seem to be moving steam. When I'm done showering the walls are wet and my shower rod and decorative fixture are rusting. I have the fan venting through a gutter soffit outside. I am not sure what to do besides taking the duct off the fan and letting it vent into the attic for now to see if it vents more steam. Any suggestions?


----------



## BridgeMan (Jan 16, 2012)

If you actually have steam in your bathroom, your water heater is set way too high.  And aren't the burns on your skin painful?

The last thing you want in your attic is moist bathroom air.  DO NOT VENT THE FAN INTO THE ATTIC.  Insulation will become saturated, mold will thrive, and you'll spend some serious bucks to correct the mess.

Far better to just check the fan for proper operation, and make sure the sheet metal duct between it and the outside is not obstructed by anything (including a malfunctioning weather flap on the outside).  If it's undersized for the room volume, replace the fan with a larger one.


----------



## nealtw (Jan 16, 2012)

You can check for air flow with a kleenex. Check it with the door open and closed, sometimes the room is to tight and you would need a bigger gap under the door.


----------



## dan897857 (Jan 18, 2012)

Well, the water temp is hotter because of my gf who loves hot hot showers. Thank you, I will check if the fan is working properly first. I would hope there is nothing wrong with it as it is new and I can hear the motor working when turned on. Do you think the airflow would be better going straight up out the roof rather than straight over and down through my gutter soffit ? There is hardly any space between the floor and door so maybe keep the door cracked open while showering ?


----------



## nealtw (Jan 18, 2012)

When you dump the moisture out thru the soffet it can be drawn back into the attic and cause other problems up there. The best is straight up with insulated pipe with a proper cap on top. If leaving the door open works, you will need to have the bottom of the door cut. You need about an inch clearence.


----------



## dan897857 (Jan 18, 2012)

Should I put insulation over the duct going out through my gutter soffit for the time being? The door def. doesn't have enough spacing but taking it off would be difficult because its a pocket door. Might cold air be blocking the hot air from going out the vent since heat naturally rises up and I have it being forced left to right ?


----------



## nealtw (Jan 18, 2012)

Have done the kleenex test yet to see if the fan is moving air?


----------



## dan897857 (Jan 18, 2012)

I will try this when I get home from work. Visually it does not seem to be sucking any steam. Its mind boggling since its a new strong fan and I hear the motor running.


----------



## MikeP (Jan 18, 2012)

I'm with nealtw, you shouldn't vent an exhaust out of the soffit if you have soffit vents. The vents are pulling air into your attic, therefore they will pull the moist warm air in and cause mold problems.


----------



## dan897857 (Jan 19, 2012)

The tissue did suck to the outside of fan cover but def isn't moving air as well even with the door cracked open with more air flow. I just read a review on the lowes website and one person claims that people who say the fan does not work well are not sealing around the box of the fan preventing air from hitting it up above. Is this something that must be done ?


----------



## dan897857 (Jan 19, 2012)

http://m.lowes.com/mt/www.lowes.com...1&facetInfo=&un_jtt_v_tabs=reviews#review_tab


----------



## dan897857 (Jan 19, 2012)

This link is my fan by the way...100 cfm


----------



## nealtw (Jan 19, 2012)

CMHC Garbage Bag Airflow Test | CMHC


These guys have a garbage bag test so you can prove how much air the fan can move.


----------



## dan897857 (Jan 24, 2012)

The fan seems to move air better when I took the duct off the fan so it vents in the attic. I don't want to leave it like this obviously so if I put the duct back on how can I make the fan move the air more efficiently ? ....insulate the flexible duct?


----------



## joecaption (Jan 24, 2012)

http://www.bathroomfanexperts.com/article.php/how-to-size-a-bathroom-ventilation-fan/?id=3

Insulating the hose has nothing to do with how many CFM of air the fan can move. It's the speed and and size of the fan blades. There's nothing you can do to make it run faster or push more air. If it's sized wrong then your going to have to add another one or replace the one you have.
The insulation is to stop the moisture inside the hose from condensing and runing back into the room or laying in the hose.


----------



## nealtw (Jan 24, 2012)

Fan to small? duct to small? duct to long? duck has to meny bends?


----------



## isola96 (Jan 24, 2012)

If the unit hold a tissue paper it's working the way it needs to nothing you can do will improve it lower it down on the steam showers.


----------



## dan897857 (Jan 24, 2012)

The duct is sized perfect to fit the hole out of the fan. The duct runs maybe 5 feet and pushed down through the soffit. It works a lot better when I took the duct off my fan. If the duct isn't obstructed the only thing I can think of is hot air naturally flows up and the cold air is restricting its movement. When the hot air is blowing down and out might the cold air be naturally blocking the warm air from moving out ?


----------



## dan897857 (Jan 24, 2012)

The duct has One end going down through the soffit. The fan is 100 cfm. Just trying to figure out why air moves better when I popped the duct off. I also have lowered the water heat down a notch.


----------



## nealtw (Jan 25, 2012)

So the duct is 3" or 4", get an adapter to 6" and change the duct.


----------



## dan897857 (Jan 25, 2012)

Ok cool.....so my solutions now are either change the duct size or vent it straight up through roof instead of down through soffit.


----------



## nealtw (Jan 25, 2012)

Do both and there will be nothing else you can do without going for a different fan.


----------



## BridgeMan (Jan 25, 2012)

Experienced sheet metal guys will tell you that you have a "junk air" problem.  A natural, relatively smooth flow of air molecules is being compromised by multiple changes in direction and small (but significant) in-line restrictions.  I strongly suspect that changing the run to vent vertically through the roof would be significantly more advantageious than going down through the soffit.   I don't ever recall seeing a bath fan run increased from 4" to 6" to improve flow in the (40) years I've been looking at them.  And a marginal fan pushing into a larger run and transition will definitely create more junk air.


----------



## dan897857 (Jan 25, 2012)

That sounds good, and the fan is literally a half foot from the roof so it would be traveling about 4 feet less than it is now out the soffit.....and of course up rather than over and down.


----------



## dan897857 (Jan 25, 2012)

I may if I get sick of it but seems like a fairly easy DIY project ......the fan installation was the hard part


----------



## nealtw (Jan 25, 2012)

When it is out the soffit the moist air will come back in the soffit vent and cause moisture problems and mold in the attic.


----------

