design
Actually we don't do this ourselves, but we work with architects who share our belief that the best way to deliver a very cost-effective sustainable house is to work on all aspects of the design together from the start.
There is no point taking a standard house and then adding a few bits on to turn it into an eco house. That is not the best way. Better to decide at the outset how the house needs to perform, work out the best way of doing it, and then make sure it also looks good and suits modern life.
"Sustainability built in not bolted on"
The houses at Diss exemplify this, in that they look like normal houses despite being very energy efficient.