ouch, 0.5w/GH isnt profitable? I'm operating 1w/GH gear still - at a marginal (~$0.75/day) loss though, but am bullish we will see >$250 sooner than the time and annoyance of putting money into an exchange
1 TH/s makes $2.44 daily income
2.44 / .5 / 24 = $.20/kwh beak even point.
Anything over $.20 per kilowatt is running at a loss.