Another amazing zero energy project in England is the Hockerton Housing Project. This project was built in the 1990s by five pioneering families, who wanted to radically reduce their environmental impacts.
I visited Hockerton in 2005 during my same trip as my BedZED visit. Hockerton is way up north by Southwell, in the Midlands. Incidentally, Southwell has a gorgeous Romanesque cathedral, promoted to cathedral status just at the end of the 1800s.
Even though zHome and Hockerton share the same core paradigm of low impact living, they go about it in completely different ways. Hockerton is completely passively heated – relying on solar energy completely. A solar atrium in the front of the homes heats during the course of the day, and this heat radiates back into the homes. The main part of the homes is super insulated, and then covered with earth. The earth acts as a heat sink, retaining heat energy over the course of the summer, and then radiating that heat back into the homes over the winter. The result is interior temperatures which rise and fall on a sine wave, peaking at 75 degrees at the end of the summer and dropping to 62 degrees at the end of winter.
This is just a quick snapshot of the project, please see their great website for more information.