Upkeep and maintenance costs are somewhat lower with evaporative cooling partially due to the technical expertise required. Operating costs are usually much higher for mechanical refrigeration. Sometimes 3 to 5 times higher in energy use alone. Equipment selection must consider the ability of the structure to support it. It is not too unusual to have to locate equipment on the ground or some other mounting method because the roof will not support it's weight.
Structural integrity is a serious consideration in selection and location of equipment.
The climate is a major consideration in the selection of cooling equipment. Evaporative cooling is especially effective in hot dry climates. Temperature drops of 30 to 40 degrees are rather easy to achieve. It is not too unusual to achieve lower temperatures with evaporative cooling than with mechancial refrigeration during very low humidity periods due the lowered performance of mechanical refrigeration equipment in these conditions. In the Southwest, it is a common practice to use both methods.