There are the following 3 classes that express the energy consumption of a building (remember that to be a KlimaHaus need a minimum Class B):
– KlimaHaus Gold classification – (Passive Houses): exhibits the lowest energy consumption of the three classes, with a heating energy consumption of ten kilowatt-hours per square metre annually, requiring practically no active heating system. KlimaHaus Gold is also called “one-litre” construction, as it requires one litre of oil (or a single cubic metre of gas) per square metre each year.
– KlimaHaus A classification: with a heat consumption of less than 30 kilowatt-hours per square metre annually, are also called “three-litre” buildings because of their usage of three litres of oil (or three cubic metres of gas).
– KlimaHaus B: a building’s heating energy consumption must be under 50 kilowatt-hours per square metre annually – the so-called “five-litre” category, which requires not more than five litres of heating oil (or 5 cubic metres of gas) per square metre yearly
The building must have a very insulated building envelope: in vertical walls, the roof and to the ground, because otherwise the heat is dispersed, and because the “hot” surfaces increase the living comfort. The thermal bridges must be eliminated, because they are the cause of heat loss and condensation problems (at times of mold) on the inner surfaces.
Another weakness of the building are the windows, you must be used tinted windows, which are able to store solar energy. The house starts to save energy when it is designed: exposure and form are important aspects, the sun and its heat are part of the construction concept of these homes.
As for the thermal plants, we are seeing a real revolution, lose power and gain intelligence, that is, ability to integrate with various forms of renewable energy (solar, geothermal, etc …).