You could probably use <1000W without it being a big deal, but anything past that and they might notice. Included or "free" electricity applies to normal electric use, not running a bitcoin mining farm.
Of course that's a generalization... you can always ask to the manager of the facility. If you're hesitant to do this then you probably already have your answer.
+1 Agreed plus the problem at these BTC prices isn't electricity anymore. Electricity is fairly cheap, however the initial investment in equipment either GPU or ASIC is considerable.
This that building a 2000MHash GPU rig is about $1200-$1500 (you have AT LEAST $1050 in three 7970's) + CPU, memory, mobo, flash drive, PSU, case(optional) etc...
that machine will produce around ~4 BTC at current difficulty so about $400 at current prices meaning your ROI is about three months without counting a huge spike in difficulty that given the facts that Avalon will be shipping batch 2 and three, seems highly likely and BFL "might" join them also...
Again, free electricity shouldn't be a big deal, but your initial investment is.
If you have the equipment already, then you should be mining the shit out of it already!