Sorry, my description wasn't clear. When a house is built and sold for the first time, the initial owners have to put money into escrow equivalent to 30 years w

Sorry, my description wasn't clear. When a house is built and sold for the first time, the initial owners have to put money into escrow equivalent to 30 years worth of projected energy use (at current rates for electric and gas). They aren't pre-purchasing energy. The escrow pays out at a fixed rate over 30 years to whoever currently owns the house. No need to track energy usage. More efficient houses (insulation, solar panels, etc) will have much less projected energy use, so far less money needs to be put into escrow, which would make new efficient houses cheaper than new less efficient houses. Unfortunately, it does nothing about existing stock.