We're installing a wall bathroom exhaust fan through an exterior wall.
The fan uses an 8'' duct. Any advice for how to cut the 8'' duct hole in the exterior wall? There are no wires or studs in the way. Are there hole saws for 8'' ducting or is our best bet to use a sawsall?
Should be about the size of a coffee can Evie, so I'd trace a can at the spot you want to cut out with a marker, drill a 1 inch hole all the way through with an elongated paddle bit and cut the rest with a 12" Milwaukee "Super Sawzall Torch Blade" in my reciprocating saw. Slick as a whistle! Hope this helps you, JL
8" seems really big for a bath fan....the last half dozen or so I have installed used 4" ducts...(dryer vent size) which can move a lot of moisture and air. Following basic laws of physics...a reduction in dia will increase the velocity to obtain the same flow rate (cfm) a 4" hole saw is a pretty common thing. and will make a perfect hole over a sawsall or jig saw.
That fact that this is a "wall" fan is why it has this jumbo sized duct...Ceiling fans use smaller (squirrel cage) type of fan blades which operate at a higher rpm. yours will have a more conventional fan blade.
a circle cutter like this could also be used...this one only goes to 7 7/8 but I have seen some larger versions.
Yes they make hole saws that size. You most likely can rent one at your local HD or rental store. Be sure to rent the drill that powers it as well. it takes a lot to turn this bit around and most home owner drills will either not be large enough to hold bit or to small and will burn out before hole is drilled.
Be careful when using this large of a bit also. If it binds it will throw you off of the
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ladder.
Sawzall would work but its harder to no destroy the outside siding and if its vinyl or some other hard cement based it will tear it up fast.
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That fact that this is a "wall" fan is why it has this jumbo sized duct...Ceiling fans use smaller (squirrel cage) type of fan blades which operate at a higher rpm. yours will have a more conventional fan blade.
a circle cutter like this could also be used...this one only goes to 7 7/8 but I have seen some larger versions.
http://www.woodcraft.com/Product/2000799/401...
Be careful when using this large of a bit also. If it binds it will throw you off of the ...»
Sawzall would work but its harder to no destroy the outside siding and if its vinyl or some other hard cement based it will tear it up fast.