what he said....the only way you would have a noticable difference in cost would be 277/480(commercial, industrial)Power(Watts) equals Voltage (120/220) times (*) Amperage (Amps). A 220 v light uses the same power as a 120 v light if they are 400 watt lights, they do not burn brighter or do anything different from an end user standpoint. they are a tiny bit more efficient because most electrical things have less losses at higher voltage levels. You won't notice anything on the bill, maybe $1 a month difference. Most ballasts can be wired to run on either 220/240 or 110/120.
Great post, you give the amperage rating for both voltage levels, cool, from that we can extrapolate how much actual efficiency bonus we see from the 240v setup.240v is good for multiple light ops. being that you draw only half the current, you can run twice the lights on a circuit that a 120v circuit could handle.
1kw 120v = 9.5 amps
1kw 240v = 4.7 amps
these are for my ballasts; results may differ.
Not my kind of smokin! You've put down some solid info but you wouldn't want to use 12/2 -3 Romex in place of 10!if you ran the same 20 amp circuit / same 12 gauge wire only this time wired for 240v you could run 4 lights .