Here's a former executive-type located in the Seattle WA who decided to live a simpler life. He installed a few solar panels on the roof of his studio and constructed a solar heater out of soda cans.
The soda can solar heater sucks the cold air out of the room, heats it up inside the glass frame and then blows the warm air back into the room. This air circulation plan works better on sunny days naturally but he claims he thinks his room is a little warmer even on cloudy days. Even the fan is solar powered. The rooftop solar panels provide electricity for his laptop and lamp.