After using a bathroom with the fan on and making an evil smell, is it more polite to leave the fan on when leaving to continue to take lingering smells away? Or to turn it off?
Assuming it’s an exhaust fan that’s drawing the air outside, absolutely more polite to leave it on, IMO. I’m curious why you might think otherwise.
Turn on the fan if you did something to stink up the room. Stinking up that room is to be expected but turn on the fan and close the door behind you. That’s why there is a fan in that room (assuming an exhaust fan).
Then do this when leaving:
What is the politeness advantage that you think this choice might have? Less noise in the building or house? Save on electricity? Something else?
Might depend on who else is within hearing range of the fan.
Some bathroom fans hit a frequency that grates on my nerves. Doesn’t seem to bother most people.
Turn it off and leave the door open. Don’t hide your light under a bushel.
Turn it on and close the door most of the way - leave it open about 4 - 6 inches. That keeps the smell in but allows for effective exhausting. If you close it all the way, it won’t exhaust as efficiently.
It depends on who else is present, and how long they’re going to be present. If nobody else is going to be using the bathroom for a few hours anyway, don’t bother with the fan.
In my small house, it’s going to be smelled in the living room and kitchen if the fan’s not on, regardless of who’s going to use the bathroom. And I wouldn’t want to smell it even if I caused the odor.
I don’t get the “leaving the fan on and walking away” thing.
You’re sending inside air to the outside. Hot or cold weather, that’s not a good thing.
Run it for a bit. Wait around. Turn it off as soon as it seems reasonable. Do not just walk away and go about your (other) business.
And … we keep a can of air freshener on each toilet. It does a great job. The actual need for fan use is small.
Air “fresheners” just add extra stink. Hate 'em.
I was traveling with friends, and left the fan on after using the bathroom. One of my friends complained that she assumed the fan meant I was still in there (she could hear it from around the corner where she couldn’t see the door was slightly ajar). Until this trip, I always thought leaving the fan on was more polite.
O my yes – I absolutely agree!
Ack!
For me, the combined smells, or even just the smell of most “air fresheners”, is worse than the smell of any shit I’ve ever smelled. And I’ve been in some pretty redolent barns.
I think that that particular friend of yours is a fussy outlier. IMO.
Replace the switch on the fan with a timer switch so it doesn’t run forever and force someone else to turn it off. That’s the only politeness issue I can see with turning the fan off. This is code for new construction or remodels in most locations. My father remodeled our bathroom in the late 50s and did that.
I don’t think it’s reasonable to expect someone to stand around and wait for the fan to do its job before leaving the bathroom. I certainly don’t have the patience for that. I would rather come back in 15 minutes, if it’s actually necessary. And I join the chorus of those who hate aerosol air fresheners. There is one called Pooph for pet odors, but I think you have to spray it right on the source of the order, not in the air.
Hm.
I do agree that in a hot cooling climate or in a cold heating climate, leaving an exhaust fan on in the lav in somebody else’s house – particularly if they don’t generally use that lav themselves – could mean you marginally increase their heating/cooling load if the fan happens to be left on for a day or two (before somebody actually notices).
But we’re really talking about very little energy waste for most people.
I’d probably hang out, wash my hands like it’s COVID days, fold the hand towel, count floor tiles, softly sing “Stairway to Heaven” to myself, and then pray to Og that the coast is clear before leaving … fan off, door open.
Another option can be … open the window a skosh and leave the fan on. Should clear the air quickly. Then, close the window and turn off the fan before making a low-key exit.
I’d rather walk into a slightly hot, stuffy, or cold lav than … um … a feedlot.
Or, I’d leave the fan on, the door either mostly or totally closed, and then – if I were hanging around that house a while longer, I’d be sure to turn the fan off after a spell.
In our house, after you turn off the exhaust fan, it stays on by a timer for about 15min. We instruct guests to just use the fan switch normally – on when you enter, off when you exit.
Or, borrow a shovel, go outside, and dig a hole. Builds character 
ETA: you could put charity over decorum, and ask your hosts which bathroom they’d prefer you ruin. Maybe the boys’ bathroom on the 2nd floor would happily take one for the team.
I think it depends on how long it’s likely to be before the next person goes in there. If it’s going to be hours, you don’t want the fan running all that time.
When I turn the fan in the bathroom on, it starts after 1 minute delay. When I turn it off, it stops after 10 minutes. Both delays are configurable. I think our first bathroom fan had similar delays, but wasn’t configurable.
The fan in my parents’ bathroom has a minimum run time of 10 minutes.
Is it so common that a bathroom fan stops immediately when turned off?
With our kitchen fan, we were instructed to always make sure to have a window open. Otherwise we would get negative air pressure. If I forget to open a window, and then go open a door, the negative air pressure flings open the door. The bathroom fan is not quite as powerful, but we usually make sure to have a window cracked open, also to make sure to get rid of excess moisture after showering.
Our bathroom fan will pull air down our chimney and make the bedroom smell like smoke if we forget to crack a window. Our kitchen hood fan is 900 cfm, but it has some kind of fresh air intake to avoid creating a vacuum.
Leave the fan on, open a window, light a candle, close the door.