I don't know exactly how many watts it is pulling, nor do I have a gauge but maybe the interface can answer your question. The power supply can be seen in the case below and a close up picture of the power supply. The tower case is a standard size case, you can see all my pictures on page 125 of this thread. The web interface shows Utility and WUtility those read 22.6 and 86.24 respectively at the current moment. I have supplied pictures of the web interface and you can see those read 32.30 Utility and 84.07 WUtility.
I am using an APC Back-UPS BN4001 as the battery backup. Used a standard 110V computer power supply cable and the miner has been running well and the boards are cool enough to touch. I'm not well versed in electricity academics so I'm probably not the best candidate to answer these questions.
From TigerDirect was $547 or 0.86somethin' BTC. Yep. TigerDirect takes BTC. Just too cool... I also have the 2.2kva one for 4 oc'd Ant s1's (1.8kw for ~800GH total - but still easily paid off and feeding themselves + profit
). Of course they display all the info you would ever want on power & condition as well with simple front panel display.