Short answer: no, a swamp cooler won't work for you.

An evaporative cooler works by evaportaing water into the air OF THE
ROOM. The evaporation cools the air and raises the humidity. It works
fine in the desert where the dew point is in the single digits. It also
works ok in more moist areas where you want to cool down a really hot
area like a furnace room or warehouse. Where it doesn't work is where
you want to keep the temp fairly comfortable AND the humidity down.

In your case, your current AC units are spending a fair amount of time
and energy ($$) pulling water OUT of the air. Using an evaporative
cooler will just be at cross purposes. Not to mention dumping a lot of
moisture into the air to rust your tools.......

You should investigate ceiling fans, floor fans, sealing up the walls,
or even a sprinkler for the roof. You might also check on the
efficiency on your exisiting units. The small 5k btu units are really
bad, going to a heavy duty 12k btu might be a better option and get your
efficiency rating up in the 12 or 13 range. A central AC unit is
expensive but it would allow you to direct cool air to your work area,
let the other parts of the shop get hotter.


Dave Lyon wrote:
While we're on the subject...


My shop is a 4000 square foot metal building with just a little insulation.
I've got 2 residential air conditioning units that keeps it bearable, but
not comfortable in our Missouri summers. I've heard that our humidity is too
high to use an evaporitve cooler in this area effectively, but I've always
wondered how one of those would do in a shop that has two central air units
running non stop. Would it actually add any cooling? Would it cause my
equipment to rust? It would sure be cheaper to operate than a 3rd AC unit.