In addition to the low construction cost, they don’t pay any bills to maintain the home. They use solar power instead of being hooked up to hydro. They collect their rain water instead of being hooked up to municipal water. They store energy from the sun in the thermal mass of their home instead of having a furnace. They use a composting toilet instead of paying to install and maintain a septic system. And they treat their own greywater (from the kitchen & shower) on site. There is a fireplace in the home, but the couple says they only use it a few times per year for atmosphere, and they don’t depend on it as a heat source.