also using a AC would increase power usage.
best way is to have your miner close to a window and try to vent the heat outside. (add to global warming
)
i did this all summer, and it dropped the temperature of the room signifigantly. (I have 4 rigs 9x5830's 6x6970's 1 6990 & 1 5970)
dropped the temp for 38 deg C to a more manageable 28Deg C