With existing technology, it is entirely possible to build houses that allow their owners to be dramatically more energy aware. For instance, it would be relatively easy to build electrical sockets connected to a house network. It could then be possible to see graphically or numerically how much power is being drawn by each socket. It would also be easy to isolate the energy use of major appliances – furnaces, dish washers, refrigerators – thus allowing people to make more intelligent choices about the use and possible replacement of such devices. In an extreme case, you could have a constantly updating spreadsheet identifying every use of power, the level being drawn, the cost associated, and historical patterns of usage.
Being able to manage electrical usage through a web interface could also be very helpful. People could transfer some of their use of power to low-demand times of the day. They could also lower the temperature in houses and have it rise in time to be comfortable by the time they got home. Such controls would also be very useful to people who have some sort of home generating capacity, such as an array of solar panels. A web interface could provide real-time information on the level of energy being produced and the quantity stored.
While all of these things are entirely possible, there do seem to be two big barriers to implementation. The first is in convincing people to install such systems in new houses or while retrofitting houses. The second is to make the systems intuitive enough that non-technical people can use them pretty well. The first of those obstacles would be partially overcome through building codes and carbon pricing. The second is mostly a matter of designing good interfaces. Perhaps an Apple iHome is in order.