Questions about installing a bathroom fan

I am thinking of installing a fan in my bathroom vent because I am having ventilation issues and I have some questions.

1. What is the criteria I should use when looking for a fan?

2. Should the fan be connected to the light switch or should it have its own switch?

3. Besides an electrician, will a contractor be needed? The vent is located above the bathtub facing the shower and it is surrounded by tile.

4. What will be the range of cost and how long should it take?

Any other suggestions will be welcome. Thank you.

Can you explain what kind of vent you have now that you want to add the fan to?

What is in the space above the bathroom ceiling? Is the bathroom on the first floor of a two story home?

Are you planning to do any of the work yourself? If you are hiring it done I would look for one guy that can do the whole job. Kind of a handyman type project I would think. It is important to get the moist air vented completely out of the structure.

mtech said:

I am thinking of installing a fan in my bathroom vent because I am having ventilation issues and I have some questions.

1. What is the criteria I should use when looking for a fan?

2. Should the fan be connected to the light switch or should it have its own switch?

3. Besides an electrician, will a contractor be needed? The vent is located above the bathtub facing the shower and it is surrounded by tile.

4. What will be the range of cost and how long should it take?

Any other suggestions will be welcome. Thank you.

Click to expand...

Answers:

1. Loudness and air speed. Loudness is measured in "somes" ... an average fan is around 2.5 somes. Air speed varies ... many places have tester setups so you can feel the draw.

2. Wall switch connection is mandatory.

3. If you are a skilled DIYer, you can install it yourself. However, it will require wiring knowledge, drywall skill, and the ability to orient the vent ducting to the outside.

4. Fans can range from $40 and up. Add cost of ducting, wire, possibly additional switch and box, foil tape, exterior vent plate ... A skilled guy can do this is 2-3 hours.

A lot of the noise from a fan is caused by the duck being to small or to many elbows.

The fan should be on its own switch as you don't need it on every time you turn on the light.
Sone ratings are noise levels. While you can get a whisper quiet low sone fan, some people prefer a little background noise while they're doing their business.
An electrician can install it but make sure it vents to the outdoors.

the other rating that gets mentioned a lot is CFM (cubic feet per minute). That refers to the amount of air that the fan can move.

I just want to thank everyone for responding to my questions

bud16415 said:

Can you explain what kind of vent you have now that you want to add the fan to?

What is in the space above the bathroom ceiling? Is the bathroom on the first floor of a two story home?

Are you planning to do any of the work yourself? If you are hiring it done I would look for one guy that can do the whole job. Kind of a handyman type project I would think. It is important to get the moist air vented completely out of the structure.

Click to expand...

The bathroom is in an apartment that is part of a larger complex. I am not sure what type of vent it is but basically it is a shared vent that is shared with other apartments. A little history, the vent does not vent properly. Odors from other apartments begin blow into the bathroom. Super has been alerted and claims it has been fixed but it has returned.

This is the closest picture that looks like the vent.

I am not doing it by myself. I want to hire someone to take care of it.

Does this help?

Your link just went to a google search. That works best if you save the image to your computer and then work thru manage attachments below.

Ducts from fans seldem tie in together even in old buildings, what you might find on the outside of the building is where more than one duct vent cover is side by side and the flap on yours might be stuck open. There is another flap on the fan housing just where the duct connects to it.
Another cause can be a shortage of air in you apartment, when you are running a range hood fan or the dryer air can be drawn back in the bathroom duct.

If this is the case a new fan will not help.

nealtw said:

Your link just went to a google search. That works best if you save the image to your computer and then work thru manage attachments below.

Ducts from fans seldem tie in together even in old buildings, what you might find on the outside of the building is where more than one duct vent cover is side by side and the flap on yours might be stuck open. There is another flap on the fan housing just where the duct connects to it.
Another cause can be a shortage of air in you apartment, when you are running a range hood fan or the dryer air can be drawn back in the bathroom duct.

If this is the case a new fan will not help.

Click to expand...

Thank you so much for your response. You bring up some great points. The ventilation system is in side the building. The only thing outside is the unit on top of the roof of the building that sucks the air out. My bathroom vent shares a line with all the apartments that are directly above and below me.

When a bathroom fan is turned off, does it keep air out? Does that depend on what type of fan is installed.

The building should be pushed to seperate the system, new buildings also have fresh air ventswhich some peole close off because fresh air is cold but they are there to replace the air that the vent fans remove. I'll bet this at it's worst when you have another fan running.

All fans come with a flapper valve. You could check yours, by removing the cover the moter can be unplugged there and then removed with a couple screws and flapper could be felt with finger at the discharge. If then you run other fans like the dryer the flapper should be closed.
For most fans anyway.

The reason I asked my questions the other day was to figure out what was going on as in your first post some of it didn’t add up.

We now know you live in an apartment and it is on some sort of a group venting system.

Your problem I believe is one you should not be trying to solve alone. You shouldn’t add a fan to a system that has a fan on the other end. I personally don’t care for the setup you describe. In most cases people renting don’t have the right to add such things on their own also.

Here is what I would do. If you are getting smells coming in from the community vent stack I would first complain again telling the manager the problem and then if nothing is done I would block off the vent in a way that wouldn’t do any long term harm and could be removed when you move out. I’m thinking tin foil and tape etc. if there is a moisture problem I would start with leaving the door open or cracking a window or in the summer even a small fan in the window if you have one.

All fans come with a flapper valve. You could check yours, by removing the cover the moter can be unplugged there and then removed with a couple screws and flapper could be felt with finger at the discharge. If then you run other fans like the dryer the flapper should be closed.
For most fans anyway.

Click to expand...

Sometimes lint or other debris & dust gets stuck in the seam or hinges of the flap, preventing it from closing. If you have access, a vacuum or a long brush can fix this.

Ok, so the purpose of this fan is to take the moisture/ stale air out of the bathroom, right?

Since you mentioned being in an apartment it sounds like your vent is hooked to ductwork.

You will need to know what size ductwork the vent uses and the CFM amount.

You will want to make sure you have something rated to be close to the shower because there are rules about things that run on electricity and proximity to the shower. Basically it can't be hit by the shower stream.

To find out what CFM you need, you need to find the volume of the bathroom. First find the wall area by multiplying the width by the length. Then multiply that sum by the height of the ceiling. Divide that number by 7.5 and you will have your minimum CFM.

So, say I have a 5' x 6' bathroom with an 8' ceiling. The volume would be 240cuft. I would need 32CFM minimum. Now, I don't think they sell them in that low CFM so I would get a little higher like 50CFM. You don't want to overdo it, but going a little over the minimum is better.

If you care about the sound then you will want low sones. I've heard that Panasonic makes some good bathroom fans, but they tend to be pricey.

There was actually an article in a Westside Wholesale thread on a plumbing forum associated with this one.

Here is the article on CFM: http://www.westsidewholesale.com/what-is-a-CFM-rating
And a companion article that explains a little about different types of fans: http://www.westsidewholesale.com/bath-fan-types

Maybe a picture of your current setup might help to visualize (ok, I just like seeing pictures).

I hope this helps.

Sorry if you already knew this info, just never know how much people know when they ask so I figure its good to cover the bases.