Energy prices are rising, climate change is leaving its mark – there are many reasons for homeowners to modernize their building in terms of energy efficiency. But what does such a renovation actually cost? An expert did the math for Capital.
Too hot in summer, too cold in winter – residents of old buildings know the phenomenon. One way of improving the living situation is through energy modernization. “There are many ways in which a house can be converted to be climate-neutral,” says Frank Hettler, head of Zukunft Altbau, an information program run by the state of Baden-Württemberg. How deep homeowners have to dig into their pockets always depends on the individual building. The expert calculated exclusively for Capital.de how much it would cost to refurbish an average single-family home from the 1970s.
window and front door
A lot of energy is lost to the outside, especially with old, single-glazed windows. Like the front door, windows are part of the thermal building envelope, so it is important that there are as few thermal bridges as possible. For a normal façade with 15 to 20 individual windows, expert Hettler calculates around 20,000 euros including the front door.
Roof
If you only want to use the attic as storage space and not as living space, you can get away with it comparatively cheaply. Because then owners only have to insulate the top floor. Hettler estimates the costs at 10,000 to 12,000 euros. Owners who want to completely renew their roof have to dig deeper into their pockets: Depending on the roof construction, the renovation costs between 40,000 and 80,000 euros for around 100 square meters of roof area with new insulation and covering.
facade
A well-insulated facade not only prevents heat loss in winter, but also ensures cool indoor temperatures in summer. In the case of old, poorly insulated facades, energy consultants recommend renovating the outer walls. Owners can fall back on various options for this, such as thermal insulation plaster or thermal insulation composite systems. These are coordinated building materials that are mounted on the outside wall of the house, for example polystyrene and a finishing layer of plaster. Price for the renovation with thermal insulation composite system: from 25,000 euros.
basement ceiling
If the cold creeps from below from the unheated basement to the ground floor, Hettler recommends insulating the basement ceiling. This is usually not too complex and costs around 10,000 euros. Skilled do-it-yourselfers can insulate the ceiling of their basement themselves and thus significantly reduce their costs.
photovoltaic system
If you want to use your own green electricity, you cannot avoid a photovoltaic system. This is particularly worthwhile for owners who heat with a heat pump or charge an electric car. Hettler calculates 12,000 to 15,000 euros for an 8 kWp system including installation.
heat pump
If you want a heat pump instead of gas or oil heating, homeowners have to differentiate between an air heat pump and a geothermal heat pump. The latter is more expensive because installers have to drill into the ground. On the other hand, geothermal heat works more efficiently than air heat and is worthwhile if there is a high heating requirement. Costs for an air heat pump: 30,000 to 50,000 euros. For the geothermal heat pump, there are additional drilling costs of 15,000 to 25,000 euros.
ventilation
Energy-efficient buildings are almost airtight to avoid wasting energy. To prevent moisture from accumulating in the rooms and causing mold to form, the residents should ensure that there is fresh air on a regular basis. However, energy consultants advise against the classic ventilation with open windows in modern energy-saving houses, as this has proven to be inefficient. A lot of heat is lost when the window is open. The solution: a ventilation system, such as push-pull ventilation. This enables a controlled exchange of air, in which little heating energy is wasted and heat is even recovered. However, such a ventilation system is not absolutely necessary. Cost: 5,000 to 10,000 euros.
total cost
The bottom line is at least 117,000 euros according to this calculation example. Whether these expenses are worth it in full always depends on the individual case. If a building is already relatively well insulated and you want to save money, owners should think about changing the heating system rather than optimal facade insulation. And: With CO2 prices rising in the future, the remediation costs could be amortized more quickly than is currently the case. Just this week, the federal government decided on higher CO2 prices as part of the climate and transformation fund. This makes heating with oil and gas more expensive.
If you want to convert your own house, you can fall back on state funds. The federal government provides 27 billion euros from the climate fund for the heating replacement alone. The state is currently subsidizing the heat pump at 30 percent. In addition, development banks such as KfW grant low-interest loans for energy-related renovations. “That also has something to do with value retention,” says Hettler. “If I don’t invest in energy-related renovation, the value of the building will drop constantly.” In any case, it is a good idea to seek advice from experts.
Source: Stern
