The guy you hired is correct; venting a bath fan into the attic is a terrible idea. You are also correct, venting through the roof avoids allowing hot humid air into the attic. However, if soffit venting is done properly, you can both avoid the hot humid air in the attic, and avoid an extra hole in your roof which reduces the chances for leaks. If you do end up with the vent in the roof, try to get it as close to the ridge as possible (the higher the roof penetration, the less water passes by it, and thus the less wear due to water, thus less susceptible it is to leak)The fans are good - I did those myself. The problem is the vent to outside.
Previously the fans just dumped straight into the attic. The guy I hired insisted venting needed to go through the soffit. I wanted to go through the roof, since the soffit is already vented. (ie. hot air would go out and then right back into the attic).
He didn't insulate the vent pipe, and the pipe filled with water and leaked through the ceiling.
So long story longer - I'm looking for someone to do a roof vent, the nearest wall is likely too far.
If the leak is due to the duct filling with water, the duct is improperly installed. Bath vents should be installed using rigid duct until the last section where they need to make turns into the soffit, at which point aluminum (NOT plastic) semi rigid flex can be used. There should not be a low point within the vent run, and without that, moisture cannot collect in the vent..
It is more common for uninsulated vents to condensate when the vent gets cold due to venting conditioned air, but the vent passes through warm/humid unconditioned space. Insulating the vent pipes can remedy this.
You are correct that venting bath exhaust through the soffit can be a concern when the soffit also venting an attic, because warm, humid air is being vented out bath vent system, and that same air can get drawn into the attic via the soffit vents. One way to address this is to block the soffit vents within 18" on either side of the bath vent. This can be done by simply laying a flat piece of wood over the soffit vents on the attic/soffit side. Ensuring you have a vent termination with both a damper and a good way to direct the air way from the soffit is also important. I really like the Panasonic EZ vents, which are also sold at the orange big box under the Gibraltar name (https://www.homedepot.com/p/Gibraltar-B ... /313487680).
Statistics: Posted by Saving$ — Sun May 26, 2024 12:33 am — Replies 24 — Views 2036