I was looking at new electric water heaters on the Home Depot site. Of course they have all sizes with variable warranties. It also list the yearly operating cost for each model. The 6 and 9 year warranty models both have dual 4500 watt elements. The 12 year warranty models all have dual 5500 watt elements. All of them with the larger 5500 watt elements had a lower yearly operating cost. Is that because the more wattage heats faster than the 4500 making them cheaper to operate? I figure also the 12 year models are more insulated than the 6 and 9 year models. So would it be the bigger element or the more insulation that makes it more efficient or a combination of both? I just always figured the 5500 watt units would cost more to run but I guess I was wrong.

I keep my WH set at 140 because I feel like I am using less hot at 140 than when on 120.(other than washer FL or DW) When I had it on 120 I used more hot and less cold in the shower and sinks. At 140 I add more cold so I am using less hot for the same uses. Maybe this isn't right either but it just seems that way to me.