I have read a lot here, about some machines needing a "ton" of power. Somebody explain to me, I thought conservation of energy applied to Chinese welders also. I got an old school transformer Tig machine and it weighs in the neighborhood around 800lbs. If I put the pedal down if sure puts out a lot juice to the tig electrode, and expectedly draws a lot of current. The machine internally does NOT give off any real noticeable/excessive heat. Therefore I assume it is reasonably efficient in converting the building power to welding power, conservation of energy and all. So other then the new inverters being magnitudes lighter, how exactly are they reportedly magnitudes more efficient in this process?

My Miller welder at 500A draws 205 Amps at 208V, a Miller inverter at 500A draws 136 Amps at 208V, that means to me there is a loss (wasted heat inside machine) of nearly 70amps at 208V, that is a lot of energy.