In Germany, less than 1% of the existing buildings are newly constructed. Most people in Germany will continue to live and work in older buildings over the next few decades. Because such buildings use even more energy than the average new construction, they offer an even greater potential for energy savings. What works for new buildings cannot be wrong for existing ones. On the whole, the refurbishment of older buildings is financially profitable – and also reduces the economy’s dependence on energy imports.
Costs and benefits…is it worthwhile?
To be cost-efficient, it is crucial to optimise the modernisation measures that are necessary anyway. The additional expense for components that meet Passive House standards is small, and the value of the building increases considerably. The chances for successfully renting out the property improve considerably. Since optimally refurbished older buildings not only ease the personal financial burden, but also the environmental impact, financial-assistance programmes are available. The German KfW bank programme supports energy-efficient refurbishment by offering low interest loans (detailed information at: www.kfw-foerderbank.de). The somewhat higher investment costs are worthwhile not only because of the savings in energy costs; the property developer’s initial outlay is reduced as well.
Refurbishment of older housing is the order of the day! The fact that it is possible to successfully equip existing buildings with Passive House components has often been demonstrated and is well proven. Almost all the advantages of a newly built Passive House can be effectively applied in existing buildings as well. “Anything worth doing is worth doing well.” Whenever a building component needs to be modernised, the materials used and the workmanship involved should be of the highest quality possible. If you use Passive House components for each modernisation measure, step by step you will arrive at an optimum level of energy conservation, maximum user satisfaction and the best economic results. This is better than making several half-hearted attempts to modernise all at once, which would compromise any future efforts to achieve low energy consumption.
The advantages of Passive House components Saving a lot on energy is only one of the many benefits of a Passive House, but a very important one. Passive House components reduce energy consumption in existing buildings by 75% as a rule, and often by up to 90%. Even more significant is the fact that the building substance of older constructions is considerably improved.
How thick should the insulation be?
In the central European climate, the economic optimum for external wall and roof insulation is currently about 220 mm at a thermal conductivity of 0.04 W/(mK). Using a future-oriented insulation thickness of 320 mm is equally cost-efficient, because it saves even more energy and provides even greater independence from energy prices. High-quality insulation is an economical form of insurance in times of energy-prices crises.