DrManhattan77

120 takes more windings of copper wire,thus more resistance, and this results in slightly greater losses in the iron core and copper windings. Because you have to provide a bigger electrical leverage or voltage, and due to facts of life with electricity, increased leverage comes with the cost of higher losses. Losses in copper/iron systems increase by the square of the current, so if we need twice the current, losses are 4 times as much, in proportion. That means that for instance a 400 watt ballast might lose 20 watts if using 240V as opposed to maybe 80 watts if using 120. Double current means 4 times the core loss, That might mean an extra 60 watts of loss, or 15% of the 400 watts. Its not allot but the more equipment you have the more it adds up 15% is 15% that adds up. And there are allot of added benefits to running things off of 240 vs 120 I would say run all that you can on 240 if you can. And no its not that hard to run 240 just have to know a little about electricity. These numbers were off my ballast and it is different with every ballast so cheek your specs.

The transformer runs cooler when powered by 240V because the primary current in the transformer is halved. So if the transformer were not cooled heat would build up more in 120v, heat increases resistance, which lessens efficiency.

Heat shortens transformer life, by melting the resins (causing the plates to vibrate, interfering with the electro-magnetic lines of force) and degrading coil wire insulation (creaing micro-shorts). Over time, the 120v transformer will consume ever more energy (because it tends to run hotter). The ratings given are just the initial ratings and not an average over the life of the transformer.[/QUOTE]