You may rate the latest eco gadget as a must for your new house but technology should be quite a long way down your list of things to do. Spending time on achieving the right design and specification will pay dividends further down the line. If you insulate it as highly as you possibly can, seal it as best you can and mechanically ventilate it with the most efficient system you can find, then the energy requirement of your house should be a lot less than if you hadn’t followed that process. Plus, none of these items should cost you a lot of money. They’re all relatively small cost items. Once you’ve determined your energy needs this way, then you could look at what’s the best, most efficient way to produce that.