Open windows and a gentle breeze cool rooms--no need for AC.
Rainwater streams off the roof into barrels, where it's saved for watering plants.
A passive solar water heater on a south-facing roof warms water 20 to 30 degrees (propane gas does the rest). This reduces gas use by 60%.
Plenty of windows illuminate the common rooms with natural light.
Twenty-four photovoltaic solar panels supplement electricity supplied by the grid. In the summer, it saves about $300 per month.
Composting and vermiculture create rich plant fertilizer and reduce waste.
Energy-efficient radiant heat panels warm rooms with less power.