Technical restrictions on retrofit insulation of buildings

Proc. eceee Summer Study 2013, 1213-1221

Authors: Peter Mellwig, Martin Pehnt, Patrick Jochum

During the process of retrofitting existing buildings, certain constructions and components cannot be insulated as required by the national regulations. These restrictions on insulation have numerous reasons, such as sheltering architectural monuments, geometry, building physics and aesthetic aspects. The aim of this project was to systematically identify these restrictions on insulation and quantify their share of the heat demand of the German building stock. Toward this end, >400 energy consultants and other experts were interviewed. The participants were asked to judge the frequency of restrictions on insulation in their daily work. The results of the survey served as the basis for further calculations of the nationwide heat loss. The restrictions were weighted by survey ranking, typical area and typical “uninsulatability”. A model for German building stock was programmed to calculate the heat loss. As the restrictions concern energy refurbishments, their percentage rises in time with the ongoing process of renovation. The course of the restrictions´ impact was shown for four scenarios. The scenarios take a long-term perspective up to 2050. A fifth scenario was calculated to show the total potential of insulation measures and the share of restrictions on insulation. The model shows that even after an ambitious energy renovation of German building stock with high standards, a bottom heat demand remains of around 42 % of today’s heat demand. About one third of the remaining heat demand consists of insulation restrictions. Most important are restrictions concerning the exterior wall (60 PJ/a heat losses due to restrictions), followed by restriction of the basement ceiling and the floor level (40 PJ/a) and landmarked building elements (20 PJ). Only future developments of insulation approaches and the use of renewable resources for heating will be able to lower the associated greenhouse gas emissions as long as the buildings are not dismantled.

Year

2013

Publication type

Refereed articles

Further content:

Energy