“I built my passive solar straw bale house with earthen plasters in 2000 for $50K (will most likely cost more today, depending on many factors). This is an overview of the house; it is extremely energy-efficient. My electric bills are about $40 per month.
This load-bearing straw bale house was built by me, Carolyn Roberts, consultant Jon Ruez, and many friends, using natural (straw bale walls, earthen & lime plasters, earthen floor) and recycled materials. We passed 23 county inspections. It’s an incredibly sturdy, beautiful and well-insulated house that will last for many years and only cost $50,000 to build (land not included).
The straw walls offer insulation from the summer heat, while the earthen plasters and floor give thermal mass to maintain an even interior temperature. The south-facing sunroom heats my home in the winter. The house uses between 5 and 10 kwh per day. I can collect 500 gallons of rainwater in a 1/2 inch rain. A hand-made solar water heater with a small tankless heater as backup provides all my hot water.”
Source: A House of Straw