The finding is most depressing: despite the billions invested in the energy renovation of buildings over the past decade in Germany, home energy consumption has remained stable. Worse: not only does the decrease in heating expenses not offset the cost of the work, but renovations often act as a factor in increasing rents, often disproportionate. Consequence: it is the poorest households that pay the heaviest price, without significant reduction in CO emissions2. GdW, Germany’s largest federation of real estate companies, with 6 million homes and 13 million inhabitants, is calling for a change in strategy.
The rebound effect
In a report published in early July, the GoW noted that more than 340 billion euros have been invested in total in the energy renovation of buildings since 2010. This work, supported by the public investment bank KfW, includes the change of windows, new heating systems and insulation of facades. However, despite huge investments, energy consumption, which fell by 31% between 1990 and 2010, has since remained at the same level. In 2010, a household consumed an average of 131 kilowatt / hour thermal per square meter. In 2018, it consumes … 130. If the trend continues, Germany’s CO reduction targets2 of homes – 55% less by 2030 from 1990 levels, 80% to 95% less by 2050 – are unlikely to be kept. Housing accounts for a third of the country’s total greenhouse gas emissions and 35% of energy consumption.
How to explain such a poor performance? The GoW highlights several causes. The first is the famous “rebound effect”: in better insulated housing, with fossil fuel prices falling since 2013, occupants are not encouraged to shy away from their comfort. Instead of heating to 20 ° C, they prefer to grow at 22 ° C. In addition, some renovations are sometimes ineffective.
“We must abandon energy renovations and increasingly expensive insulation”, Axel Gedaschko, president of the real estate federation GdW
This is the case with heaters, which, poorly calibrated, consume as much as the old ones. Insulating the facades on the south side also has a counterproductive effect if it prevents the building from heating up with the sun’s rays. The president of the GdW, Axel Gedaschko, therefore recommends changing the criteria to define virtuous habitat: we must stop looking at the theoretical energy consumption of a building, but measure the actual CO emissions2, which must be awarded a price. “We must abandon increasingly expensive energy renovations and insulation, and opt for decentralized low-carbon energy manufacturing, with digital emission avoidance techniques,” Mr Gedaschko said.
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