How eco will you go?: Self-build advisor John Corless delves into the question of energy efficiency, airtightness and the environment, and why the decision of how eco you want to go has to be taken early on. This, in large part, has to do with buidling a low energy home, and the need to commit to this building route from the start. But also consider the lifecycle of the products you use, water usage and other lifestyle considerations such as transport.