stackable washer/dryer clearance

[Laura Turner]

I'm planning to put a stackable washer and dryer in a very tight space.  Manufacturer's specs indicate a minimum of 5" behind the unit.  Why?

There's space behind the washer for the dryer exhaust, which can go down through the floor.  And I should be able to fit the supply lines and drain there.

The only problem, and the only reason I see for the 5" clearance in back, is the vents on the dryer.  I'm concerned that dampness would damage the wall.  The salesman assures me that the vents are for air intake only and the unit can go flush - that if I open up the wall there will be sufficient air intake from the air between the studs - but of course he'd say that; he's trying to sell me the unit.

Comments?