So sayeth Nick "Two potential improvements: 1) exhaust house air to an
attic ("upducts")
or some other cavity bordering an exterior surface, eg a garage or
sunspace
or storage space, and thereby reduce the usual conductive heatflow from

the warmer outdoor air into the living space, or 2) use a humidistat
and
a reversible fan like Lasko's $55 2155A 16" window fan (90 watts at
2470 cfm
on high speed) and Grainger's 2A179 $88.15 programmable cycle timer and

its $4.37 5X852 octal socket to periodically reverse the fan direction
when
it needs to run, making a "Shurcliff lung" that turns all the cracks
and
crevices in the house envelope into bidirectional air-air heat
exchangers. "

If you were still on the indoor evaporative cooling scheme and then
exuasted the humid room air into the attic. This would make the make
the space below the attic negative with respect to the outdoors and the
attic positive with respect to the outdoors . An attic could tend to be
a bit of a solar collector and this ventialtion shceme could push air
hotter and more humid than the ambient down around recessed light
fixtures, junction boxes for ceiling fans etc. and into the living
space below

Likewise exhausting to an attached garage could pressurize the garage
and make the home negative with respect to the garage. So with this
pressure differential, air could flow from the garage and into the
home. Not a good scheme should there happen to be a car idling in
there. Could be a CO risk.