I want to get a DALI controlled house where I can set light, heat and water electronically from anywhere in the world. You can preprogram it to turn devices on and off at certain times of day or in certain situations for maximum efficiency. You can use occupancy sensors so that no energy gets wasted where its not going to be used by a person. You can set it to gauge ambient light and heat and only produce enough extra to reach a basleine level that you set. You can track exactly how much energy has gone into which socket at what time of day to find ways to save even more energy. Just watch out for when the house gains self awareness and puts you down the garburator.

If you paired that system with an efficient building envelope (lots of insulation, lots of double glazed windows, no leaks), geothermal heating with radiant dispersal, on-demand water heating (no tank), a green roof with solar panels, and efficient appliances you would be in a seriously energy efficient and easy to live in home. You can use a sh*tload of high quality recycled building materials these days as well