They use a fair amount more energy, most wash motors of this vintage draw about 4 amps vs. modern units at 0.75-1.5 amp. The heater is resistive so it's about the same. The wash cycle for an older machine like this is going to be much shorter though, so the energy offset isn't nearly as much as you'd expect. It will definitely use a few extra gallons of water in a cycle, but again, not a massive increase but one that will add up over several years of ownership.