What’s the mileage on your house?

The price of petrol is one of the most important signals in the climate/environmental discussion. It’s so visible; we can follow the prices rising and falling advertised with big signs along the roads. Most have a pretty good idea of how far their car drives pr. Litre - and of course we do, because we’re confronted with the economic consequences every time we fill our car.
The cost of heating our houses or the price of electricity is a different matter. Very few know the price of a kilowatt hour, or how much it costs to operate their appliances – even though 40% of our energy consumption is spent in our houses, much more than for transportation.
We’re not as aware of whether our house is efficient or not, because we’re not confronted with the information. Experiments have shown that simply installing a gauge that tells the driver what mileage he or she is getting currently improves the fuel economy considerably.
My guess is that if it were more visible, in realtime, how much we’re spending to heat or cool our houses, or to use our devices and appliances, we would save a lot of energy and create a huge demand for energy efficiency in buildings.