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?
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.
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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...