Having a small unit might not just be too keep your energy costs low and to reduce your carbon foot print, it can also give you extra income by selling any excess energy you have to power companies. This could be a fun look for trailer parks and other area where land is limited, but population sizes are not. Having a small unit can be a great way to have enough space for a small yard or garden. The homes will be sold at different scales with the high end having composting toilets and recycle water systems.