How to Reduce Your Energy Consumption.
In a 2001 study of typical US homes it was found that AC and the Fridge takes up 30%, space and water heating took up another 30%, and lighting was 9%.
If a person drops AC, uses a solar hot water system for water and space heating, uses a refrigerator like the Sun Frost RF16, and goes from incandescent to CFL lighting — that would save you about 50% of your utility bill.
See Solar Water Heading Information
The design of your dwelling can cut down on consumed energy. When designing your home you should use design considerations like well sealed, well insulated, proper site orientation to southern exposure, suntempering, balance heat gain and heat loss in window selection, optimum mass-to-glass ratios, shading, natural cooling, natural lighting, and right sizing South-facing overhangs.
See Considerations for Building a More Energy Efficient Home
See Incorporate Energy Conservation and Efficiency in Home Building
I am thinking about building a small 16′ x 24′ cabin with a gambrel roof using the above considerations. Bedrooms would be above the living area in the gambrel roof.