In the 60s of the last century still believed almost all oil is cheap and everlasting. Because of the cheap oil buildings became built which count today as derelict construction sins. Heat insulation thanks! There is enough oil to the combustion! The inside of the walls was cold in winter, the surface of the radiators very hot. In the warm upward wind zones by the radiators dust became whirled upwards.
Because of the cold wall surfaces the air temperature had to be surely high, so that a person feels fine there from the temperature. However, high air temperature lowers the relative air humidity. This means hot very dry air for feeling bad.
Expensive energy creates high-quality solutions
A difference almost already as largely as between sky and hell is between the ill houses of that time and the most modern construction technic from today. Wall heating in capilary tube technik with a preliminary heat temperature only 7 degrees about ambient temperature. The windows of today have a better heat insulation than the walls of this ancient cheap oil time.
A controlled living space airing with heat recovery creates a steadily good aerial quality. Permanente air exchange realized technically. Because the walls are much warmer - more than 10-fold better heat insulation in comparison to the wrong times of cheapest energy and the wall heating - the air tempeature can be much lower with the same thermal well-being. This creates a higher relative air humidity and avoids the health load of extremely dry air.
Progress for more residential comfort which we owe to the energy becoming more expensive.