When insulating a building, insulation materials are installed in or on the building and old windows are replaced. In addition, air passages in the building envelope are sealed to prevent draughts. As a result of these measures, heat is better kept in the building. However, building insulation not only serves to prevent heat loss, but also to protect against heat. A green roof, for example, protects against overheating, retains rainwater and also visually enhances the building.

To increase living comfort and energy efficiency, a heat recovery ventilation (HRV) is also installed, which ensures a constant supply of filtered fresh air and removes pollutants from the room air. The heat from the outgoing air is recovered by a heat exchanger.

In general, a building to be insulated should be as dry as possible and the relevant building elements should be load-bearing enough. Otherwise, it depends on the individual case, as each building is unique and has its own characteristics. An expert should therefore identify the most suitable measure and material in each case. In addition, an energy advisor can support you in applying for funding from BAFA and KfW. It does not always make sense to insulate all building elements at the same time or at all in order to avoid undesirable side effects such as mould formation due to moisture. A building should therefore always be considered as a complete system and not just the individual building elements.

In general, the older your building is, the worse it was insulated during construction. Existing insulation does not equal good insulation.

In the long term, professionally executed building insulation is always worthwhile, as it permanently reduces the heat demand of a building. In combination with heat recovery ventilation (HRV), the heat demand of a building can be reduced to almost zero, depending on the type of construction. This is the case, for example, with a passive house.

Many parts of a building can be insulated without construction measures in the living space. Even for buildings where it is not possible to heavily insulate all building elements, the standard of a zero-energy house or plus-energy house can be achieved in combination with a photovoltaic system and a heat pump. In this case, the remaining heat demand is met or even exceeded by renewable energies. Depending on the efficiency standard, up to 75 % of the costs are covered by BAFA and KfW subsidies.