Bathroom vent fans, good or bad?

[Ole Anderson]

And use insulated vent pipe, whether rigid or flex, otherwise moisture will condense on a cold pipe in the attic and drip back down in the room.

[Lee Schierer]

And use insulated vent pipe, whether rigid or flex, otherwise moisture will condense on a cold pipe in the attic and drip back down in the room.

Sloping the pipe slightly toward the outside will prevent this. I don't think code allows flex piping anymore.

[Ole Anderson]

Sloping the pipe slightly toward the outside will prevent this. I don't think code allows flex piping anymore.

Best solution, but difficult to do of you have to go through the roof.

[Jim Matthews]

Plus one on the Panasonic fans and routing outside the house envelope.

[Rollie Meyers]

In my rental wired the fan to come on with either the overhead or the light over the mirror, as it has been vacant for almost 2 years, do not know how well it will work but going to find out soon when it becomes occupied this weekend.

[Charlie Velasquez]

Sloping the pipe slightly toward the outside will prevent this. I don't think code allows flex piping anymore.

They make a condensate fitting that can be installed near the fan and under the attic insulation, or is easily insulated. Condensate collects and then flows downhill through a tube and out the eaves or soffit. Never see them in the US, but saw a number of them when in Europe.

[Andrew Seemann]

The old man ran some of that 3 inch flexible ducting for a bathroom vent though an uninsulated attic to a roof vent. After a winter, the fan didn't seem to vent well and it smelled a little musty. In spring we went up into the attic, and saw that it had sagged into a U shape which had filled completely with water that had condensed on the sides of the ducting. We ended up taking out the extra length and wiring it to a board to keep it straight from the fan to the roof. I would be surprised if it had not frozen during the winter as well.

[Brice Rogers]

In most of our bathrooms, I installed a timer. That eliminates the chance that it'll be running all day.

In our powder room off of the living room I had the opposite problem. My FIL would use the toilet, really stink up the place and NOT turn on the fan. Talking to him didn't do any good. Sometimes when we had company, and I noticed the smell from another room and I would have to go in and turn on the fan. But then another well-meaning guest would go in and shut it off.

So I ended up putting in a motion controlled fan switch. So if someone walks in, the fan will run for the next 15 minutes. It may be programmable but I've never bothered to change the setting. Interestingly, some of the solid state motion switches aren't compatible with a motor and won't work. I had to get a slightly better unit. My guests haven't figured out how to de-activate it (yet).

[Ole Anderson]

Interestingly, some of the solid state motion switches aren't compatible with a motor and won't work.

I recently bought motion detecting light switches for church. One restroom had a fan. At HD I noticed they had one motion detection room switch rated for light motor use. Seems to be working fine. Only problem I ran into is that they all require a ground (and neutral) wire in order to work and some of our restrooms had been remodeled by a contractor that wasn't apparently qualified as an electrician and just ran two wires to the light switches, no ground or neutral. That is one reason Michigan code now requires light switches to have a neutral and ground even if the neutral isn't being used initially. That one tripped me up on the rough electrical inspection for my son's basement project.

[Brian Elfert]

I recently bought motion detecting light switches for church. One restroom had a fan. At HD I noticed they had one motion detection room switch rated for light motor use. Seems to be working fine. Only problem I ran into is that they all require a ground (and neutral) wire in order to work and some of our restrooms had been remodeled by a contractor that wasn't apparently qualified as an electrician and just ran two wires to the light switches, no ground or neutral. That is one reason Michigan code now requires light switches to have a neutral and ground even if the neutral isn't being used initially. That one tripped me up on the rough electrical inspection for my son's basement project.

The neutral for switches thing is part of the national electrical code now. There was no reason in the past to run a neutral to a switch so the contractor didn't screw up there. (No ground is an issue.) Code requires a neutral now because of all the timers, smart switches, and the like that require a neutral.

[Andrew Pitonyak]

The vent fan in our bathroom doesn't use duct piping. It just vents into the attic area. I haven't noticed any adverse affect on our heating/cooling bill. BTW, it only pulls 60 cfm's.

Does this room contain a shower or bath? If you have lots of moisture that you dump in the attic, that can be a problem. There was mold in the attic of my house before we bought it and this was listed as the probable cause. it was mitigated before we actually bought the house.

If there is no shower or bath, probably less of a problem, but, venting warm air into a cold attic could cause issues I suppose.