I wanted to ask your opinion on the duct termination for my 2 bath exhaust fans.
The question I have is for the termination of one of the fans. It would be easier for me to cut through my cedar siding to do a side wall termination. It would be about 12 -15 feet total vent length. If I did the roof I would need to hire someone to vent through the roof(About 3 feet)
Dave…side wall vent should be fine with that fan and why cut another hole in the roof…15 feet should be no problem with which ever material You choose to work with
just make sure You have a check valve in there for back flow wind and I would say across the floor is fine…
I would suggest the easiest install
12-15 feet is not too long and I would also use a flex it’s easier to maneuver around. [FONT=Comic Sans MS]I would also recommend arching the flex piping to prevent water intrusion at termination. [/FONT]
That’s a good question; you would think that metal for the most part would out last the plastic vent cover by far and a few years ago that may have been true, but with the improvements they have made with plastic materials it’s hard to truly say.
I would suspect the life expectancy of the plastic vent cover would be determined on the extreme weather conditions it had to endure, quality of the plastic used and location.
I personally would still arch the last few feet of the flex vent piping above the termination point (vent cover) this will help prevent any possible chance of water running back into flex piping in the event of water intrusion. Just a thought.
If the total length of exhaust pipe is in the cold attic above the insulation, it should be insulated for its length to prevent interior condensation. I have seen a water filled droop in a flexible plastic pipe that blocked all ventilation. There was about 3/4 quart of water.
If the pipe is run in a heated space, then the last 3 feet at the exterior wall should be insulated with an airtight vapour barrier over it to prevent condensation on the exterior of the duct and consequent dripping. Small amounts of cold air bypass the damper into the duct or the air in the duct become cold (not an insulted damper) and condensation on its exteior occurs.
I be darned if I would of went 15 ft to a side wall with a roof within 3 feet $350.00 for a roofer to do what cut a hole in the roof and install a rain cap duh I would have taken the roofer on the roof and pushed him off and screamed $350.00 just as he hit the ground.
Roof vents of some nature are installed on every roof out there what is the big deal about another one. Sometimes you guys advice is off the wall pun intended
Well said. On Monday I inspected a house with a decent quality range hood installed. It ends there.
The installer went against the manufacturer’s instructions of 6" diameter (28.3 sq in) or 3 1/4 X 10 (32.5 sq in) ducting. He installed 4" diameter (12.6 sq in) spiral wound aluminized ducting, essentially dryer ducting. It was about 20’ to a side wall while a roof vent would have about 3-4’ of duct.
Spiral wound duct acts like ducting of 1 size smaller, so this 4" duct is performing like 3" (7.1 sq in) straight smooth duct! So this is essentially a working condition that is 75% smaller than recommended.
It was uninsulated through a cold attic on top of the insulation batts.
Like I said, a decent medium quality range hood only. Wonder how well that will work?