[mchannon]

There are two approaches worth considering.

Evaporative cooling is not worth doing in Boston for the space in a residence. It can be used, however, to improve the efficiency of refrigerated air units. Take a look at air conditioner misters that spray hose water onto the radiators for refrigerated air units. Although I suspect a good percentage of that heat is carried away simply by conduction rather than evaporation, it could conceivably cut your air conditioner bills. Water-cooled whole-house air conditioners are high maintenance, otherwise they'd be commonplace.

The other approaches involve tag-teaming a refrigerated air unit with a swamp cooler. The air intake for a refrigerated air system would work a lot better at 80 degrees, 80% humidity than 90 degrees, 60% humidity. I am told this is commonplace in Phoenix.

One other often-overlooked characteristic of the "swamp cooler zone" is that it tends to be at high altitudes, which aside from keeping things dry and cool enough to have a shot at good-enough cooling, requires doubling the size of refrigerated air units to keep pace with design specs. The air is thinner enough up here that the radiator can't keep up as well. This shifts the balance slightly in the direction of swamp. This has been what feels like an unusually hot and humid summer in Albuquerque, and our household finally sprung for a room air conditioner, run in parallel with the swamp.