#1 Has anyone used this in Seattle area on hot summer days?
Yes! Have central air in the house but the venting system doesn’t cool well enough to the upstairs. Use it in the master bedroom for extra cooling on hot days; which aren’t too many in Seattle but a very nice to have for sleeping comfort.
#2 How often do you have to change the water if you just use the fan, and not the cooler?
We don’t because research showed it works better for cooling by not filling it full. If we run the fan the water evaporated on its own.
No you don't need to have it near a window. The idea is to let the air circulate. If it's out in a roomy area is fine not closed up in a room. I have mine in an open doorway blowing in the direction of the room I'm in..