Designing Kitchens and Bathrooms - bathroom ventilation fan exhaust

Can a bathroom fan be vented up to top of attic area just under an attic ventilation area? It is not closed to the ventilation cap, just a flex duct sitting directly under the area that is open. Two bath fans are leading to a connector by flex then one flex is open three inches below an existing attic vent. Contractor says hot air rises and this is just fine. I thought it had to be an enclosed area all the way to the outside. Please advise.

Individual exhaust fans require individual exhaust ducts. These exhaust ducts need to be terminated to individual roof jacks (vent outlets) going through the roof.

If I understand what you wrote the contractor connected two fans to one duct using a TEE or WYE connector and then ran the outlet near an attic ventilation vent. If this is what was done it is incorrect.

what about products like this ?

http://www.americanaldes.com/sv160.html

that is a booster fan that runs continousy to ventilate several spaces.

your question is not electrical, but building code. consult your local building dept.

Mack, I agree with furd. I'm a computer man by trade. I base that statement on my recent experience of installing a bathroom exhaust fan in my house as there was not one.

My main concern was the warm, humid air not escaping the bathroom. (House was built in the 60's.) In the attic, I ran aluminum flex hose from the fan up to just short of the vent. This was a run of about 10 feet. They're the roof mounts that spins. I did this based on recommendations from two different handymen. Warm air rises so that does make sense.

The other alternative would have been to install a vent as close to the exhaust fan as possible. This would involve cutting a hole in the roof. If I had went that route in my setup, I would have installed another vent 4 feet away from the existing vent. The extra hole in the roof isn't worth it to me.

You may want to also post your question in:
DoItYourself.com Community Forums > Plumbing, Heating, Cooling, Air Conditioning and Filtration Systems > Ducting Systems, Air Filters and Ventilation

One final thought, what did you contract with him to do? If he said he was going to install a vent and did not, that's a different story.

I asked 3 HVAC companies when they were installing my heating/air about a similar situation.

I have my bath exhaust fan discharging (bad terminology) into my attic. The flex duct is goes up and is attached to a truss.

All 3 companies said it is fine like this.

I guess it would be up to local codes?

Pretty much, yes. But I've never lived anyplace where that was legal - even if it was I wouldn't do it.