Around a fifth of all CO₂ emissions in Germany are caused by heating buildings. A large lever can be applied here if emissions are to be reduced. But the starting point is not the same everywhere, because there are measurable differences when comparing the energy efficiency of cities.
The most energy-efficient city in Germany is Potsdam, according to an evaluation by the ImmobilienScout24 platform for the Federal Association for Energy-Efficient Building Envelopes (BuVEG). The so-called median apartment consumes 85 kilowatt hours of heating energy per square meter and year (kWh/m2a). What is meant is the apartment that is right in the middle of the list of properties listed according to energy consumption. Bremen comes last in a list of the 50 largest cities in Germany, where the apartments consume a median of 130 kWh/m2a.
Between August 2021 and August 2022, almost 540,000 rental and sale offers for houses and apartments were looked at. Offenbach comes in second behind Potsdam with 87 kWh/m2a. In the previous year, the 132,000-inhabitant city in Hesse had led the ranking. It was then that the award for the most energy-efficient city was presented for the first time. Overall, the average energy efficiency value for the properties examined has improved by an average of three percent compared to the previous year, says BuVEG Managing Director Jan Peter Hinrichs.
From his point of view, it is striking that eastern German cities in particular have better energy efficiency. "This is obviously due to the numerous building renovations since reunification," explains Hinrichs. "And there are many city administrations that care." According to the expert, there are also active administrations in Hesse. Last year's winner, Offenbach, achieved its good energy efficiency through a high rate of new construction. "This is due to a special subsidy for energy-efficient construction in Hesse. Something like this also exists in Austria and Italy,” says Hinrichs.
Winner Potsdam now gets a prize, presented in the Federal Ministry of Economics. "Especially in view of the war in Ukraine and the impact on energy prices, there is an urgent need to drastically reduce consumption in buildings," says Potsdam's Lord Mayor Mike Schubert (SPD). "The city is being rewarded with this prize for its ambitious approach in recent years," comments the politician.
Berlin did poorly. The capital only manages 23rd place in the evaluation, making it the last of the eastern cities on the list. The remaining 27 positions are then exclusively in western Germany. The worst performers are cities in North Rhine-Westphalia.
Meanwhile, the BuVEG bestows its award in its well-understood self-interest. After all, the association, founded in 2016, represents manufacturers of bricks, windows, doors, facades, plaster systems and insulating materials - or as Hinrichs puts it: "All trades involved in the building envelope".
The aim of the association, namely to generate good business for the members, can now be equated with the social goal of reducing the CO₂ emissions of residential buildings. Not only the BuVEG, but also the other associations of the housing and construction industry have long been calling for an increase in the renovation rate - from now one percent per year to two percent in the future. Because at the current pace, it will take 100 years for the building stock to be properly renovated, say the experts.
If the quota is doubled, it will take "only" 50 years. According to Hinrichs, that's not a record speed either. "In order to make significant progress in reducing the energy consumption of buildings, it is essential to increase the refurbishment rate nationwide in Germany."
There are enough reasons for this. With the Ukraine crisis and the associated increase in energy prices, an important one has also emerged: "Unrefurbished buildings will probably continue to lose value in the future compared to refurbished or new buildings," says Hinrichs. The additional energy costs that owners are currently facing and are likely to face in the next few years, especially in the case of old buildings, will have to be deducted from the value.”
In another evaluation for Hinrichs Verband, ImmobilienScout24 compared the sales prices of 200,000 renovated and unrenovated houses in September. The result: Buildings in Germany with high energy efficiency achieve up to 35 percent higher prices and are 67 percent more in demand than comparable properties that have not been renovated. The peak of the price reduction of 35 percent for an unrenovated house was reached in rural areas. Overall, the difference between unrenovated and renovated nationwide is 22 percent.
“It used to be assumed that energy-related refurbishment serves to maintain the value of a property. We are now seeing that energetically fit houses achieve far higher market prices,” says Hinrichs. "Anyone who invests in the building envelope of their property will not only save a lot of energy in the future, but will also significantly increase demand and value."
The current situation even shakes an old real estate credo: the saying “location, location, location”. In the future, von Hinrichs will have to say "location, location, ... energy efficiency" when it comes to describing the attractiveness of a property.
How energy-efficient your own apartment or house is can also be determined without an energy consultant. "Regardless of whether you are a tenant or owner: All you need is the value of the building's total heating energy consumption in kilowatt hours (kWh) and divide this by the heated building area in square meters," says the co2online energy portal. This value is then compared with the appropriate comparative values in the energy efficiency table and then provides information about the building's efficiency.
You can then see very quickly in which class from A to H your own apartment is. Incidentally, the differences between the winning city of Potsdam and bottom of the table Bremen are only one or two classes: C to D or E. Efficiency house standard is not one of these classes.
It only starts with B. The consumption in kWh can be found in the annual bill from the supplier or landlord. With Heizspiegel.de, Co2online also offers a simpler and more accurate way to check the efficiency of your own building. "In addition, you will receive suitable tips on how to reduce consumption and improve building efficiency," promises the portal.
The past also proves that the renovation is worthwhile. "Since 1990, more than 40 percent CO₂ has been saved in the building sector," says Kerstin Andrae, General Manager of the Federal Association of Energy and Water Management (BDEW). But not only the building shell is important. Today, every fourth heating system in Germany is 25 years old or older and no longer works efficiently. "This potential urgently needs to be recovered - the faster, the better," says Andrae. "A modern gas heating system can already be operated with biogas and, in the future, with hydrogen without major conversion."
But for the effective use of heat pumps, building renovations are central, as they are particularly suitable for houses with high building efficiency. Hinrichs sums it up: "Even heat pumps have to save."
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