My woman comes from Romania. She has experienced herself how the people were compulsive-made happy in winter with very low ambient temperature. Continental climate with cold winters, practically uninsulated primitive concrete constructions and a dictator looking only on exports and granted nothing to his slaves, the population of Romania.
In 1989 the fair destiny has overtaken this dictator. The brother-in-law of my woman has now in Sibiu a business to install gas heating systems in houses, because even with very limited money, nobody wants to freeze.
Modern solar technology instead of heroically freeze for the environment
We need electric power. A lot of electric power. As the very first and cheapest renewable energy source the water power was used. However, this is almost no more developable. The second renewable energy source was the wind power. However, there are also limits for the growth of wind power. If still more electric power is necessary, the next more costly method is required: Photovoltaic, the direct conversion of light to electricity. Best all roofs photovoltaic only
A combined module Photovoltaic can deliver in Germany per year typically 100 kWh of electricity and 500 kWh of warmth. With the combination module the warmth is, so to speak, a cheap waste product of the electric power production. The surpluss warmth is stored under the house.
In winter the warmed up subsoil and a wall heating with only 7 degree Celsius above room temperature brings unusual high efficiency for the heat pump.
preliminary heat temperature allows an unusually high achievement number for warm pump to only 7 degrees about ambient temperature.