On 8/25/2017 6:26 AM, DerbyDad03 wrote:
I have a 8 gallon wet-dry vac that I want to put inside a cabinet. Roughly 24" x 24" x 29". The hose
and cord will come through a hole in the side. The door will be a simple overlay style with a latch.

I'm trying to save space but also keep the noise down.

Do I need to add some holes in the back for exhaust? The cabinet certainly won't be air tight, but is
the door and hose hole enough?

Unless you intend to open the door when it's running or the hole for the
2" hose is 8" in diameter, my guesstimate is "No!" You're going create
back pressure, just like shoving a potato in an exhaust pipe.

If you really want to put it in a cabinet and cut down noise, I would
experiment with a downward vent or some other form of baffling/muffler
in the cabinet design. First thing that I would try would be to build a
simple box 24" square by 29" high, turn on the vacuum and lower the box
over it, leaving maybe 2" between the bottom of the box and the floor.
If that muffled the sound sufficiently, I would then remove one side of
the box, replace it with the door you describe, and cut my holes for the
hose. Then, instead of just letting the cabinet sit on the floor, I
would attach four legs (simple 2x4's with the tops bevel cut so they
don't act so much as a shelf to catch dust and crap) to the corners of
the box to keep it 2" off the floor. That will provide for a more or
less unrestricted air flow from the vacuum's exhaust.

There are a few other things you could do to accomplish the same thing
and maybe even make it quieter. You want to lengthen the path of the
exhaust flow without restricting it. The bottom line is that "what goes
in, must come out"