Houses that don't burn fossil fuels

[jimad]

Not exactly an electrical energy source, but rather like electric cars something that doesn't burn fossil fuels.  As you know the vast majority of gas poured into a gas car is turned into wasted heat.  The vast majority of gas, or wood, or coal, or fuel oil that is burned to heat houses is rapidly wasted too.  German "PassiveHaus" designs are house designs that avoid 90% of this wasted energy.  Most of their heating comes from the "waste" heat produced by the normal electrical appliances they contain:

http://www.passivehouse.com/