Inspired by the thread about roof vents, I want to know whether bathroom ceiling vents (in toilet area) actually do any good? In my experience in apartments and houses they are cheap pieces of crap that make a lot of noise and hardly move any air out of the bath. Perhaps they manage to help a bit with shower steam but that’s aided by the heat of the steam.
Perhaps with everything being so airtight these days, there is no extra air available to be “sucked” out.
I believe that they must have started being required by code at some point because I’ve never seen a bath without them in decades. If that’s true, what is the code enforcing? No stinky allowed?
Ventilation is needed not just to remove odors but to also keep collected moisture from deteriorating the structure. Codes often require only a window, which may never be opened, so I’m not sure how much necessity there is. Many apartments don’t have a fan in each bathroom, all the bathrooms will be connected to common vent shafts, which usually have a fan, but maybe not. Good quality fans will clear the room of moisture and odors without making a lot of noise. I’ve heard a lot of good remarks about Nutone bathroom fans, low noise and long lasting. Most fans state the noise based on ‘sones’. I’ve seen them as low as 1.5 sones. Over 2.5 sones they can get pretty noisy. Some reduce the noise by lowering the volume of air moved.
Vent fans vary widely in quality and performance. We finally got a high performance one for our bathroom, and it works so well you can feel the breeze.
The industry term for these is “fart fan”, for what it’s worth.
The efficacy is usually determined by how the duct is run. If it travels a long way to get to the outside, it may not draw a lot of air. I’ve seen some that don’t even exit to the outside. Those are useless.
Most of the modern ones I encounter work quite well.
That’s partially true. In my house there’s a vent, that runs from the side of house, into the basement, and connects to a return vent. Took me years to figure out what it was for. Finally, one day I was watching an episode of This Old House and they had the same thing on one of their houses and it was explained there. It’s to bring in make up air when you run a bathroom vent or kitchen exhaust. With houses sealed up so tight (windows and doors anyways) there’s really only three ways for fresh air to come in when you turn on those vents. 1)Soffit vents and then through your attic door, which brings in dust. 2)Small cracks/drafts in the sheathing/cladding of your house, through the insulation and then through outlets/breaks in the drywall/into your basement etc. Again that can bring in dust/fiberglass etc and 3/Cracks in your foundation or even your basement slab (radon?).
So a solution is to install this vent. When you turn on a vent, the negative pressure in the house is relieved by bringing in air through this vent, which gets pulled in through a return duct and through the filter in your furnace. If your furnace/AC is on, it’ll get heated/cooled at the same time.
The house I saw was a ‘smart house’. When you turn on one of those items it was run through a heat exchange so that the outside air was tempered to more closely match the inside air before it entered the living space.
Saw something about this for houses in the far north. They get sealed so tightly an intake vent has to be added to provide air to the furnaces, both for the flue draft and to have a sufficient supply to burn fuel efficiently.
that is heat recovery ventilation. you might have exhausts in kitchen and baths with returns elsewhere. this be controlled by humidistat and on demand (timer button) in bathrooms.
so functioned as fart fans and provide whole house air exchanges.
Some friends had a new house built to their own design (with an architect). The living space had a real fireplace, as much for effect as for warmth and, of course, a chimney.
When they moved in they lit the fire and the room soon filled with smoke. Naturally they called the builder because they assumed that the chimney was blocked. Eventually they installed a ventilation system, because the problem with the fire was simply that it wasn’t getting enough air to make a draught up the chimney.
Hot water boilers here are usually fitted with a built-in system.
The houses I saw being built a couple of decades ago didn’t have bathroom fans that duct to the outside; they just blew air into the attic. Was that the usual way back then, or was I just witnessing very shoddy construction?
It’s not uncommon. I know when my parents added bathroom vents to their house about 10 years ago they just ran the vents right up near the roof vents. It was a lot easier then climbing up on a steep second story roof. When they reshingled last year they fixed it. Their attic is fine as far as I know, but if you had poor or no venting, you’d end up with a horrendous mildew problem. Possibly even to the point of structure starting to rot.
You want your attic to be the same temperature is it is outside, that’s the point of the soffit/roof vents. If you ran your (vented into the attic) bathroom vents to push hot air out of the attic, that would imply you’re doing it during the summer when the AC is on. Doing that would cause the cool hit the hot humid attic air it would essentially end up raining in your attic. There’s no way that would end well. You’d wind up with either mold on the underside of your roof decking, the top side of your drywall, or you’d get lucky and the just wind up losing the R-Value your insulation as it absorbed all the moisture and flattened out.
Fortunately, most people only run the fan for a few minutes here and there, lets say an hour a day total. That’s probably not enough to do anything, but you really don’t want cooled air getting into your attic in summer or heated air getting up there in winter. Both can be very bad and expensive problems.
A Kleenex will easily test a bathroom exhaust fan. The fan should suck the Kleenex up to the grill and hold it in place. If it doesn’t than the fan may be underrated for that room size or theres a venting issue.
sizing chart for required cfm rating on bathroom fans. Most bathrooms are 6ft wide (width of the tub on back wall) and about 10 ft deep. 8 ft ceilings. 480 sq ft. depending on duct length a 70 cfm should be fine. I’d prefer using a 90 cfm.
If people use them for odor control, doesn’t that mean the fan is sucking up all the poop particles from the toilet bowl and spreading them all over the bathroom?
