Assuming most people have radiators to heat their homes, a more sensible solution would be to come up with a more efficient heat storage medium than water. Good old H2O has one of the highest specific heat capacities (SHC) of any liquid at room temperature. In other words it requires more energy per kg to heat than any other liquid.

If we could come up with a new, synthetic inflammable liquid that had a much lower SHC we could massively lower carbon footprints, energy bills, energy use and costs by retrofitting existing systems to take the new liquid and seal them off from the water mains.