Remember that modern heating and hot water systems have a >1 COP, meaning basically they provide more heat than the input power. Air-sourced heat pumps can have a COP of 2-4, and ground source can have 4-5, meaning you can get around 1800W of heat out of that 450W of power. That's ignoring places like Iceland where geothermal heat can give you effectively free heat. Ditto for water heating, 2-4.5 COP.
Modern construction techniques including super insulated walls and tight building envelops, heat exchangers, can dramatically reduce heating and cooling loads.
Just saying it's not as outrageous as it might seem.
