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pesphoto 12-27-2007 11:05 PM

bathroom exhaust vents into attic
Bought a house recently. The bathroom exhaust was installed by previous owner. Thing is that it doesnt vent out of the house. There is no vent hose attatched to unit, it just vents right into attic. Is this bad? I will have this fixed soon, but what can happen if left this way? Thanks!

ACobra289 12-27-2007 11:26 PM

You are correct. It's not good for it to be vented into the attic. During winter conditions attic frost is a problem associated with moisture from inside the house. When warm air from inside the house escapes traveling up through the vent, the moisture condenses on the roof boards and rafters, where the frost can form. When the outside temperature rises again, the frost thaws, water collects and can leak into your house. If the water stays in the attic, mold can be a potential problem.

Get that taken care of as soon as you can.

Chris Johnson 12-27-2007 11:59 PM

Make sure you insulate the pipe as well, or better yet buy insulated pipe and use that

pesphoto 12-28-2007 07:01 AM

Thanks guys. teh only part of this IM not sure I want to do myself would be going out on the roof, we have a pretty high and steep one. Not afraid of heights but....If I were to call a pro what specialty does this fall under so I know who to call. I took a closer look and where the exhaust is placed in the attic it would only take a few feet of pipe to get it out the roof.

hvac122 12-28-2007 03:12 PM

Call your local HVAC pro. They will know what to do.

pesphoto 12-28-2007 03:15 PM


5kimprovements 01-04-2008 08:51 PM

fart fan....
if your attic is vented properly a little extra humidity up there shouldn't cause any problems....when i bought my house i noticed that my fans vent into my house was built in 1988 and in 20 years there is no moisture damage on the ceiling or in the attic.....also i live in chicago it gets plenty cold.....

Spike99 01-04-2008 09:42 PM

To me, all bathroom exhaust fans need to vent "outside". Either to the side of the house or out through the roof. NO bathroom fans should vent into the attic.

In my area, building code clearly stats that exhaust fans must NOT vent into the attic. They need to vent outside. Not too sure what the old building code was but if the new building code states to vent bathroom fans outside, it has its reasons behind it. re: Moisture, frost, mold, etc. etc.

If this was my home, I'd bring it up to "new" building code - before costly damages start appearing.

BTW: Before adding insulated vent piping to your existing fan, do confirm the CFM (vent power) of your existing fan. If previous home owner installed it, they probably went for the lowest cost exhaust fan (instead of proper CFM size fan). Measure your bathroom square feet and confirm the existing fan is of proper "CFM size". If needed, purchase a proper (or slightly larger) bathroom size exhaust fan. Most often, the fan's exhaust pipe size determines what size of "insulated piping" is needed in the attic. For good CFM chart, surf:

Hope this helps as well....


5kimprovements 01-05-2008 08:33 AM

you are all a bunch of alarmists......

Spike99 01-05-2008 08:46 AM


Originally Posted by 5kimprovements (Post 85800)
you are all a bunch of alarmists......

Call the building inspector or a home inspector in your area. Ask them if venting a bathroom fan directly "outside" is mandatory. If one lives in Mexico or some other hot climate, the answer might be NO. In my area and many other areas, the answer is YES. It's mandatory from a building code and "common sense" perspective. Why play "russian roulette" (sort of speaking) when one doesn't have to. It only takes a simple phone call to obain a YES or NO - for one's specific home...


pesphoto 01-05-2008 09:23 AM

When we had our house inspection the inspector definately pointed it out saying it should really be vented outside. So i think by code it should be, but in reality it doesnt really do a ton of harm as it is. But I will at some point vent it outside. Why take a chance in damaging your home if it is something that can be easily fixed.

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