EnEV 2014: High cost, limited effect

The German government’s roadmap, which aims at lowering CO₂ emissions in the building sector by a total of 20 % by 2020, is worthy of support to the full extent. But how an EnEV that categorically excludes refurbishment with regard to energy requirements is supposed to make a key contribution to this is more than questionable: after all, the annual number of newbuilds makes up less than one percent of housing stock in ­Germany.

With two times 12.5%, the EnEV draft plans a nominally stricter tightening up in the primary energy sector. With heat losses of up to 50% from ventilation and an already very high-quality building envelope today – thanks to appropriate masonry products, these stricter requirements lower the transmission heat losses of newbuilds by just around three percent. Similarly limited are the results for CO₂ emissions: in practice for a detached house with four occupants, emissions will be reduced by just 130 kg/year. These 130 kg don’t even match the amount of CO₂ caused by the annual consumption of chocolate in a four-person household!

Since the early 1990s the German clay brick and tile industry has taken key innovative steps and lowered the thermal conductivity of its masonry bricks by a total of 60%.

Thanks to such high-quality masonry products, today just 12% of the energy losses from a building can be attributed to its walls. Against the background of the 130 kg CO₂ to be saved in total, with regard to the exterior walls we are talking about just 15.6 kg CO₂.

You therefore rightly have to ask just how reasonable the balance of cost and effect of the EnEV 2014 really is.