My wife and I are planning to build a highly insulated property that is not served by mains gas. The property will also have solar PV panels for renewable electricity supply, solar thermal panels, MVHR and rainwater and grey water harvesting. We are now confused to how best to heat both the space and water in an efficient and eco-friendly manner. The obvious choice is an air source heating pump, but because of the high insulation and solar gains the number of times it would actually run seems to be debatable and seems hard to justify the cost of the pump. We have thought about installing a wood stove for additional heat during the coldest periods of winter, but this does not solve the problem of the best way of heating the water. Can you advise us which would be a) the most economical option to install and b) the most efficient in our circumstances.