Anyone who buys or inherits an older house is obliged to bring the heating and thermal insulation up to date. But there are exceptions.
Last but not least, climate change and the supply bottlenecks in gas and oil make it clear that resource-saving behavior is required. The legislator sees a need for improvement, among other things, in old buildings that are often unfavorable in terms of energy consumption. Therefore, when there is a change of ownership in an old building, there has been an obligation to renovate since 2020 - for buyers and heirs alike.
"As soon as a new owner is entered in the land register, the so-called retrofitting obligation comes into force," explains Gisela Kienzle, architect in Landshut and consultant for the Bavarian Consumer Advice Center. Owners would then have two years to replace or improve the boiler and the insulation of certain pipes and the top floor ceiling. Because only these three points are mandatory according to the Building Energy Act (GEG).
But only boilers that are more than 30 years old, i.e. that were installed before 1991, would have to be replaced, says Kienzle. It also only applies to boilers that are not designed for condensing technology or low-temperature heating. "But most of the boilers are not operated for 30 years anyway," says Christian Handwerk, consultant for energy-efficient construction and building physics at the North Rhine-Westphalia consumer advice center in Düsseldorf.
Corinna Kodim, an energy expert from the House Owners' Association, estimates that if there is an obligation to replace it, the installation of a new condensing boiler could currently cost between 10,000 and 12,000 euros
In addition, exposed distribution lines, i.e. for hot and drinking water, must be insulated in unheated rooms. That applies to the basement, says Handwerk. "The costs are low, for one- to two-family houses, owners could even buy sets in hardware stores or on the Internet." This measure also pays off quickly and is therefore in the interests of the owners.
The top floor ceiling is the ceiling from the top heated room to the attic. It must achieve a certain thermal insulation value. "To put it simply, this value indicates how much heat is lost through a component," explains Wolfgang Szubin, building consultant for the Association of Residential Owners in Bonn.
Christian Handwerk estimates that the ceiling must have at least an insulation layer of around four centimeters so that insulation does not apply. "This is a minimum standard that thermally protects against structural damage such as condensation." Anyone who is obliged to retrofit must insulate much thicker - about 14 centimeters. It is also possible to insulate the roof instead of the ceiling.
"Most houses already meet the prescribed values," says Kodim. However, it is often worthwhile to improve the insulation. According to Kodim, the costs would be - depending on the size and material of the ceiling - at a maximum of 2,000 to 3,000 euros.
Anyone who has renovations carried out in accordance with GEG must have them approved by an expert for thermal insulation, says Christian Handwerk. The confirmation must be kept for ten years and presented to the competent authority if requested.
The law does not impose any further direct obligations on new owners. But Kienzle points out that even with voluntary modernization, rules must be observed. Anyone who wants to renew the facade or windows, for example, can do so on a small scale - ten percent of the affected area - without specifications. "In addition, legal regulations then apply," says Kienzle.
"If I want to have different windows installed, for example, I have to know which ones suit the building so that mold doesn't develop afterwards," she explains. When buying, homeowners are required by law to check advice on energy performance certificates. If a free initial consultation is offered - by a self-employed consultant or a consumer advice center - they would have to take advantage of it. But even if not, energy advice can be useful.
Under certain circumstances, owners can have measures promoted, be it with grants or low-interest loans. There are several offers at federal, state and regional level, says Kienzle. "Some subsidies can be combined by homeowners, others are mutually exclusive."
VWE construction consultant Szubin refers to the state credit institution for reconstruction (KfW) for the energetic renovation and to the Federal Office of Economics and Export Control (BAFA) for the promotion of renewable energies. "Basically, it is important to know that applications for funding must always be made before the start of the construction project," says Szubin.
(This article was first published on Friday, August 12, 2022.)