# Bathroom Fans and Energy Efficiency



## mknmike (Feb 5, 2011)

I am in my mid 40’s and until a couple years ago, I hadn’t ever really thought much about the fact that when the bathroom fan runs, it blows conditioned air outside and therefore is contributing to infiltration in other places by reducing the pressure in the home. 

Since I find my kids now leaving the bathroom fan on when they depart that smelly room (which I appreciate), I’m planning on installing timer switches to have the fans automatically shut off. 

Should timer switches for bathroom fans be a part of new building code in order to be greener? Might it already be code in some locations? I understand that spending $10-20 for a switch that’s more likely to be problematic isn’t something that everyone wants to replace that $0.30 switch that works reliably forever. 

I guess I will have to try it out before forming an opinion. 

In my effort to be green I find myself annoyed when I wake on a freezing cold morning to find one of my kids went to the bathroom after I went to bed and left the fan on all night long. I’ve introduced them to the concept of the bathroom fan wasting energy and how maybe lighting a match is better than leaving the fan on all night.


----------



## Bud9051 (Nov 11, 2015)

Reducing the amount of air the bathroom fan blows out is not necessarily a good thing. There are way to calculate how much is desired and they have "delayed off" switches to provide the desired run time after exit.
Bottom line is, all homes need to replace the stale indoor air rather often. For many homes that means a complete air change every 3 hours.
How old is your home?
Have you ever had the air leakage measured?
One of the delayed off switches would eliminate the fan being left on for hours in exchange for a specific run time after every use.

Bud


----------



## mknmike (Feb 5, 2011)

Bud9051 said:


> How old is your home?
> Have you ever had the air leakage measured?
> One of the delayed off switches would eliminate the fan being left on for hours in exchange for a specific run time after every use.
> 
> Bud


This house is over 90 years old, but I still don’t want the bathroom fan running all night long.

Edit: never did a leakage test but I can feel the cold air coming in through all doors all the time when it’s cold. 

I bought a timer switch with times that I think would be appropriate. Bathroom Fan Auto Shut Off 30-15-10-5 Minute Preset Countdown Wall Switch Timer White 30-Minute https://smile.amazon.com/dp/B01M4IF...t_i_QH0QD56RBFKRVDFBVHHJ?_encoding=UTF8&psc=1

I think our bathroom fans work well, and when I redid our kitchen and the powder room that’s in it, I specifically chose a loud fan that moves a lot of air. I figured nobody wants to smell or hear someone busting ass in the kitchen or dining room. So a loud fan is good. 

Anyway, I was curious as to whether newer green building codes demand timer switches for exhaust fans. In ~25 years of home renovations, I’ve never used one before.


----------



## SLSTech (Jan 19, 2021)

Likely to make it into codes - yes / no / maybe - but more than likely no - it all comes down to submissions made & how the reviewers see it
One problem is ventilation standards where exhaust only is an acceptable path i.e. running a bath fan 24 x 7
2nd is not everyone needs to run it all the time listed or at all - shoot some may need it to run more than 30 minutes FAQ: Should I always use the Bathroom Fan when taking a Shower? (thehtrc.com) 
3rd is many manufacturers offer a humidity control sensor feature in some models to automatically turn them off when the humidity level drops so they wouldn't like a mandatory timer being required. FYI I am not a big fan of those systems, but they can work for some locals - humid areas not so much
Overall it is a great idea & I have seen some builders that do install them as a normal feature, but most leave it to the HO to do if they so choose


----------



## lenaitch (Feb 10, 2014)

I don't know what the Code is but HRV exchangers recover heat from exhausted air. In some installs I have noticed, the bathroom fan just kicks the HRV fan onto high speed. A timer on a bathroom fan is a great idea.


----------



## mknmike (Feb 5, 2011)

I fell asleep on the sofa last night to wake to the sound of the upstairs bathroom fan on all night again. It’s my fault for not getting up and going to bed in which case I would have shut off the fan, but this is exactly the type of scenario that living with kids / teenagers creates, and IMO, it’s not green. I was only planning on installing the timer in the powder room downstairs, but my wife asked me, “do you think that’s going to look tacky?” I guess tacky is the word for something that wasn’t in her parent’s house. And if it’s not normally seen in residential applications, then people will think it’s weird. I guess I might also think most solar panel installations look tacky too. Decisions.


----------



## Oso954 (Jun 23, 2012)

I don’t like many of the electronic countdown switches. They either take multiple button pushes to set, or close attention to what button you are pushing.

I like the old fashioned clock spring timers. You can by them in various max durations. 
I like the without hold timers. Whether you talk about “hold” or “manual on” on an electronic timer, kids or spouse learn to use it and the fan may still run until you notice it.









Intermatic FD30MWC 30-Minute Countdown Wall Timer for Fans and Lights, White - Spa Equipment And Supplies - Amazon.com


Intermatic FD30MWC 30-Minute Countdown Wall Timer for Fans and Lights, White - Spa Equipment And Supplies - Amazon.com



www.amazon.com


----------



## SteveTheRock (11 mo ago)

I installed a couple LUTRON timer switches to shutoff our bathroom fans a few years ago. I was also concerned with our teenage son not shutting the fan off.

You set the timer once with the rocker on the right and moving forward you just press once to turn it on, press again to turn it off. I think they're great and look sweet.









Lutron Maestro Countdown Timer for Fans or Halogen and Incandescent Bulbs, Single-Pole, MA-T51-WH, White - Wall Timer Switches - Amazon.com


Lutron Maestro Countdown Timer for Fans or Halogen and Incandescent Bulbs, Single-Pole, MA-T51-WH, White - Wall Timer Switches - Amazon.com



www.amazon.com


----------



## mknmike (Feb 5, 2011)

SteveTheRock said:


> I installed a couple LUTRON timer switches to shutoff our bathroom fans a few years ago. I was also concerned with our teenage son not shutting the fan off.
> 
> You set the timer once with the rocker on the right and moving forward you just press once to turn it on, press again to turn it off. I think they're great and look sweet.
> 
> ...


That does look nice. Certainly not cheap at $42.90 though.


----------



## MTN REMODEL LLC (Sep 11, 2010)

I like your ide..think it's smart.

On those timer switches,youmay want to check and see if you have a neutral available at the switch for the timer.

If not, you can find some timers that do not require a neutral and are permited for using the ground.....(very minimal current to the ground.)


----------



## Old Thomas (Nov 28, 2019)

Use a timer. Or lay down the law about turning off the fan.


----------



## ddawg16 (Aug 15, 2011)

I redid our original bathroom when I added on to the back of the house which resulted in loosing the window. Hence, I had to install a vent fan (80 CFM) wired to the lights. And since no one in my family knows how to turn off a light, much less a vent fan, I installed a Lutron occupancy sensor switch. When you turn on the light, fan comes on. As long as you're in there, like taking a shower, the fan is running. I have it turn off 5 min after you leave the room.

The fan I have is too small. I'm redoing the bathroom again (converted it from bathtub/shower to a walk in shower. In the process I noticed all the hardware is rusted which means the moisture is not being removed. So now I'm going to install one of these...









It's intended for 'grow operations'. Moves 195 CFM, 35 db sound level and uses less power than the existing vent fan.
I'm going to remote mount it from the bathroom. In other words, I'll remove the existing vent fan, put in a 8x8 register with 6" outlet with a reducer to 4". Hard pipe over about 8' to the fan...the piped another 6' to the exit thru the roof. 

The existing vent fan is kind of noisy 

I'll document it when I do it and post up here.


----------



## sestivers (Aug 10, 2007)

I prefer the switch that Oso mentions, too. And I think it's going to be greener in the long term to use the fan too much rather than too little. That way you won't have to eventually replace materials that got moldy or soft from being damp all the time.


----------



## mknmike (Feb 5, 2011)

sestivers said:


> I prefer the switch that Oso mentions, too. And I think it's going to be greener in the long term to use the fan too much rather than too little. That way you won't have to eventually replace materials that got moldy or soft from being damp all the time.


Powder room next to the kitchen is the one that bothers me the most. With this logic, you should also run the vent hood for your stove all the time. 

We like to run the bathroom vent a few extra minutes to assure the next person who enters doesn’t get suffocated by the stench.


----------



## sestivers (Aug 10, 2007)

mknmike said:


> Powder room next to the kitchen is the one that bothers me the most. With this logic, you should also run the vent hood for your stove all the time.
> 
> We like to run the bathroom vent a few extra minutes to assure the next person who enters doesn’t get suffocated by the stench.


Alright, well it takes a simple quarter turn of that switch I have to get 10 minutes or so, no fiddling with little buttons trying to get the time you want. You might not like that the dial won't go backwards, so if you turn it farther than you mean, or just want it off, your only choice is to wait for it to finish.


----------



## Arelia (7 mo ago)

Hi
have you considered installing a shower timer with cut off in your bathroom or in your children's bathroom
therefore, you can restrict the maximum shower time
regards


----------



## mknmike (Feb 5, 2011)

Arelia said:


> Hi
> have you considered installing a shower timer with cut off in your bathroom or in your children's bathroom
> therefore, you can restrict the maximum shower time
> regards


Nope. That’s an interesting idea. It never even crossed my mind. That would be nice to assure there’s hot water for the next person, but how would it work? Require someone to turn it on outside the bathroom, so they need to get completely out of the bathroom to turn it off? Or just have an alarm that goes off to remind someone how long they’ve been in the shower and not have any functional effect, just psychological?


----------



## Arelia (7 mo ago)

mknmike said:


> Nope. That’s an interesting idea. It never even crossed my mind. That would be nice to assure there’s hot water for the next person, but how would it work? Require someone to turn it on outside the bathroom, so they need to get completely out of the bathroom to turn it off? Or just have an alarm that goes off to remind someone how long they’ve been in the shower and not have any functional effect, just psychological?


hi Mike
this is one of the advantages: it assures water availability, otherwise some members in the family will have to go to work without having a proper shower.
It turns on by just opening the tap; if you shut the tap in the middle of your shower, the countdown stops and goes into Soaping time; then you reopen the tap to get rid of soap and will start taking shower time off where it was left; once you have ran down all the shower time, the shower timer will block the inner valve for a preset Delay time; when this delay or waiting time is over, it will go back to shower mode and another shower will be available; By the way, when you have 1 minute left for showering, the display will star flashing first in green and the last 30 seconds in red, to warn you are running out of shower time.
In add to this, it has a *water leak sensor*, if someone leaves the tap open, when it returns to shower mode, Acqua Tempus will detect the tap was left open and will automatically shut the tap off till another person gets into the showertub and reactivates the shower timer by pressing the Arelia button

this video is very simple , you can watch it here; it is from a customer in the US, testing it in the basement of his house
hope this helps


----------



## Arelia (7 mo ago)

and the last important thing: it has a security seal not to be switched back to it original position and override it
you can see it here
regards


----------



## snic (Sep 16, 2018)

Oso954 said:


> I don’t like many of the electronic countdown switches. They either take multiple button pushes to set, or close attention to what button you are pushing.


I have this switch, which is very easy to use:



HVACQuick - Marktime 42E Series Fan/Light Time Delay Switch (Toggle)



Basically, up means "on", all the way down means "timer", and in the middle means "off". The disadvantage is that the user doesn't get to set the time (that can only be done by removing the faceplate and using a screwdriver - once it's set, no one can monkey with it without removing the faceplate). The advantage is that it's incredibly easy to use. And if you have the lights wired into the same switch, you can set it up so that the lights are off when the switch is in the "timer" position, and the fan will stay on until the timer expires.


----------



## Oso954 (Jun 23, 2012)

That a nice option.

However, I still like a clock drive countdown timer on the fans. Simple to use and extremely reliable. They come in a lot of different max settings, but I like the 30 in bathrooms.








Intermatic FD30MWC 30-Minute Countdown Wall Timer for Fans and Lights, White - Spa Equipment And Supplies - Amazon.com


Intermatic FD30MWC 30-Minute Countdown Wall Timer for Fans and Lights, White - Spa Equipment And Supplies - Amazon.com



www.amazon.com





When I had young kids in the house, I would put both the lights and the fan on the one switch. 
That took care of remember to use the fan and don’t forget to turn lights off.


----------



## snic (Sep 16, 2018)

I replaced two of those clock dial fan timer switches in the house I bought a couple of years ago, because both were broken. In fact, I think I've seen more broken switches than functional ones in people's houses. They do wear out. (That said, I have no idea how long the 3-position switch I installed will last - I actually brought that with me from the old house, so it's been 5 or 6 years and counting...)


----------



## SW Dweller (Jan 6, 2021)

check this out





__





Products - JonEvac


JonEvac products of ventilated toilet seat vacuums and removes unpleasant odor and bacteria directly from the toilet bowl.




jonevac.com


----------



## u2slow (Feb 9, 2012)

If you don't purge damp air from your bathroom you will develop mold problems. I put in a 5-30min timer at first, but I need to change it to a 5-60min version.

A lot of new home construction around here runs a programable timer and a humidistat on the main bath fan; the local switch ends up being a manual override.


----------



## snic (Sep 16, 2018)

u2slow said:


> If you don't purge damp air from your bathroom you will develop mold problems. I put in a 5-30min timer at first, but I need to change it to a 5-60min version.
> 
> A lot of new home construction around here runs a programable timer and a humidistat on the main bath fan; the local switch ends up being a manual override.


Our master bath is very large and even after replacing the fan with a higher capacity in-line fan (300 cfm), I found I had to program the timer to stay on for 60 minutes. It might be a bit overkill, but on cold days I notice condensation on the window which drips down onto the wooden window sill, and that will eventually cause rot. Even at around 60 min there's still some condensation on the window.

The reality is that there was no way to duct the fan without a long duct run with 2 or 3 curves. Long runs and turns greatly reduce the actual cfm - it's probably 100 or less. So even though I can stick a piece of paper on the grille and it stays put when the fan is on, it just takes a really long time to thoroughly vent the room. I like the humidistat idea - with that I'd have some confidence that I'm not over- or under-doing it with the fan on time.


----------

