Bathroom exhaust

What is the maximum length that a 6inch flexible duct coming from a bathroom fan can be from the bathroom to the roof penetration?

I got the answer I was looking for

What is the answer?

It depends entirely on what the manufacturer states in the instructions included with the unit.

Cop out.

The most popular is that light in the middle with four sides drawing in air.
Curious myself.

What is it …24 feet for dryers? (never see brand mentioned)

40 feet for Cat 4 exhausts. (had to look that one up last week)

Someone post the answer but please do not copy from another site so we do not get blacklisted…:slight_smile:

It’s not a cop out by any means.

Do you have some code reference or rationale or is it your gut speaking again? :roll:

Comparing the heat from a dryer with the moist warm air from a bath exhaust is just plain silly Bob.

Your warning is even sillier as there is no law in place at this time to make that happen.

No law yet.Just stay to the left Mike and keep walking .

I am asking a simple question as to the average.Sorry if this is a debate?:roll:

Poor Roy, as now I know how he feels every time you jump all over his posts.

You are making claims you back up. Why?

James -

You’re getting a lot of bum info on here. To start with as everyone knows here in Kansas City our builders take pride in going the extra mile to ensure a quality product. You NEVER vent bathroom exhausts outside in the cool air OR where pests could get inside. The proper way is to take them into the attic then cover them with 7" of insulation so they don’t get cold and to hide them from pests, etc. This also helps provide a little more humidity into those dry old attics (functions like humidifier).

Anymore questions just ask a KC home inspector OR codes inspectors.

I was assisted by many members when installing my own exhaust fan.

With there help I was able to save $$$ and do a darn good job!! Link to my post and an illustration to use in reports.


No limit in the code.