'Bosch Net Zero' home leaves owner with no energy bill - In 2010, in the nippy environs of northeastern Canada, a family of six submitted to an experiment. Their task: spend one year living in one of the most energy-efficient homes built in North America.

A 1,700 square foot house costs roughly $150,000 to $170,000.  The Bosch Net Zero house cost $499,000.  The difference then is $329,000.  Even without considering the mortgage interest, to pay for itself in 6 years, the savings in energy usage of all types--electricity, gas, heating oil--would have to be $4569/month.  Even at the projected future price of $210,000 the savings in energy would have to be $556 per month--again disregarding mortgage interest costs.  And, there is a big assumption that the price can drop from $499K to $210K.