Requires that the heat requirement for new buildings (greater than 50 square meters) be covered proportionately with renewable energies. The owner can determine which form of renewable energy is to be used. Establishes a certain minimum proportion of the total heating and / or cooling needs to be generated by renewable energies. The proportion depends on which renewable energies are used: Solar radiation: at least 15 % of the heating and cooling energy requirements of the building must be covered by a solar thermal system Solid or liquid biomass: 50% Geothermal energy: 50% Establishes replacement measures. Renewable Energies Heat Act