Sancho: thank you for helping explain this to me, but I'm still puzzled.
Firstly, Debbie said a zero carbon house is one that generates over a year as much energy as it uses or more.
I queried this, pointing out that generating energy can be done in different ways, with different amounts of carbon emission, and you clarified that what was meant was that the energy generation in question was achieved in low or non carbon emitting ways like solar heating, photovoltaic panels or wind turbines.
But surely then it is the energy generation that is carbon neutral and not the house. And it wouldn't make any difference if that energy was generated by, say, a wind turbine on the roof, or by a wind farm a few miles away that supplied whole streets.
I know I'm often sarcastic, but I'm not now making fun. I'd fully agree that the less emission the better, but I'm struggling to understand this concept of "net zero emission" as the property of a single house, and I'm starting to wonder whether it might not be a misleadingly individualised target.