I've always heard/read that keeping it to under 1K per bedroom in the house keeps you pretty low on the radar....if on it at all.
We finally hooked up a nice industrial timer for our water heater, so it only heats a couple hours a day...when we need the showers and such. That made about a $20 difference on the elec. bill. That allows another 400-600 watter running for flowering without any change on the bill.
But, like mentioned....keeping it to a pair of 400's or 600's would raise any eyebrows at all. The electric guys want to make money, so pay the bill on time and don't steal power.
If you are still on the fence, just peek at this chart and you'll rest easy once you know how much it costs to run your equipment.
http://lib.store.yahoo.net/lib/speci...lectricity.pdf
Peace, be safe - OGH