I got a notice this week that NStar has applied for a rate hike for NStar Green, the optional program where people pay extra to support energy generation by renewable sources…. NStar markets the program as if 100% of your electricity will be from renewable sources, and I think it’s this approach that turns people off. It all goes into the same grid, so no electricity is “my” electricity. The premium that I pay only makes a difference if NStar is actually buying more renewable energy because of it. Is that the case?

Ironically, we converted our toilet to dual-flush before we switched to a low-flow showerhead. Changing showerheads is one of the easiest things people can do to save water and energy. According to the EPA, showers represent 17% of indoor water use. And it’s heated water, too.

This weekend we participated in a weatherization barnraising organized by the Cambridge Home Energy Efficiency Team (HEET). No, we weren’t weatherizing an actual barn; neighbors from all over Cambridge got together to help make two homes more energy efficient. We worked on things all over the houses, from installing aerators and low-flow showerheads to insulating.

We finally got that Kill-A-Watt we’ve been thinking about, and we spent a good part of last weekend running around the house measuring the energy use of every single piece of electronic equipment we own. It was surprisingly fun. It was also a lot of numbers. (See below.) But we could draw a few conclusions from all of them:

People can be very proud of their particular dishwashing methods, but the most-quoted study, from the University of Bonn, has shown that a full dishwasher load washed by hand takes an average of 27 gallons. Even the most efficient handwashers used 8 gallons of water. By comparison, an Energy Star–qualified dishwasher uses less than 5.8 gallons per load.