Agreed with john, we're currently having AC fitted into an IT room that regularly gets over 30C at present (flat roofed, takes the full beating of the sun). £5k total, with wired remote. There are additional costs, as we have to have them tested etc, but it'll be more than worth it. Can't speak for evaporative cooling as we only have a small amount of active cooling in the place. The extractors they fitted in one refurb here are useless and noisy.