How long should we run our bathroom exhaust fan after showering?

[Cyllya]

IIRC, when I was little, I heard you shouldn't run the fan for very long because it was a fire hazard, but I might be misremembering. Plus I'm in a pretty dry climate, and our home has a painfully low RH level right now, so I wanted to leave it off and let the moisture spread throughout the house. (But would that actually work, or would too much humidity stay in the bathroom?) I tried to google this info, but it's like everyone expects everyone to know how long to run the fan. My family never used those fans when I was growing up though, so I have no frame of reference.

My humidiphobic fiance wants to run the fan for up to eight hours after every shower.... Maybe I should just buy a humidity meter for every room in the house.

[yeahwhat]

10-15 minutes should be enough.  If you have low humidity, open the door and put a portable fan in it to pull the moist air into the rest of the house. 

[dbsam]

It might depend upon your fan too.  We've recently replaced several of our bathroom exhaust fans and the new ones really work quickly. (We leave the fan on while we shower and for 5-10 minutes after the shower.) 

We use the fans a lot - showers and 'bathroom courtesy'.  Many years ago my husband installed timer switches on all of our bathroom fans - they work great.  We never heard about the fans catching fire, but we didn't want them running all day because they take out the heat/ac, wear out the fans, waste electricity, etc. 

[elsie]

As long as it takes me to get dressed and dry my hair (15 minutes or so)

[nd_deadhead]

I installed a bathroom fan 2 years ago, with a timer. It worked great - until the timer burned out. I replaced it with a regular switch.

In a dry house, I wouldn't run it as long (in the winter). Do this test - close the bathroom door during a shower, run the fan, and see how long it takes before the condensation on the mirror clears off. I'd run the fan a bit longer than that.

And we always shower with the door open, to help move that moisture to the rest of the house.

[cristeen]

First thing to do is see if it's doing anything.  Take a Kleenex or 2 squares of TP, flip the fan on, and hold the tissue in front of the fan.  It should suck it onto the grill.  If it doesn't, then there's no point in turning it on at all because it's not doing anything.  I'd look into replacing it. 

Assuming it's doing something, we run it until the mirror is no longer fogged, with the door open.  Which is going to be dependent on the time of year and the ambient temp/humidity level.  When I get out of the tub, I open the door, turn on the fan and in the winter it might take 10 minutes for it to clear.  In the summer it sometimes doesn't fog to begin with. 

[NikonMama]

We only run the fan as long as it takes us to shower, dry off, and comb our hair.  Once we leave the bathroom we shut it off and just leave the door open. 

[carlbarthel]

I keep the door open for sometime and keep the fan on for around 10minutes. Another reason to keep the door open is that our bathroom vanity cabinets is not waterproof so very often water does get sprinkle on it causing it a damage.

Edited by carlbarthel - 8/21/12 at 9:13pm

[ollyoxenfree]

Our bathroom fans are fairly noisy and the sound annoys me. I feel like I'm always turning them off after people (DH) let them run on and on and forgotten about them.

I'll run the fan during and after my shower. I'll open the door as soon as I'm dressed and leave the fan running while I dry my hair or brush my teeth or whatever and maybe for another few minutes - approximately 10 minutes after the shower ends.  DH seems to think that it needs to run for 30 or 60 minutes or more. I think he just forgets about it and it doesn't bother him at all. It's funny because he grouses if lights are left on after someone leaves a room.