Disaggregating the causes of falling consumption of domestic heating energy in Germany

Consumption of domestic heating energy (space and water heating combined) in Germany has been falling in recent years. Official figures indicate it fell by 17 % in 2000–2011, from 669 to 564 TWh (temperature adjusted), while the population reduced by 2 % and the number of occupied dwellings increased by 3.4 %. German policy has strongly promoted deep thermal retrofits through regulation, information campaigns and subsidised loans. An important question is what portion of the reductions are due to progressive energy efficiency upgrade policy and what are due to other, non-technical factors such as demographic and behaviour change. We use national statistics and existing empirical studies to disaggregate the contribution of energy-efficiency improvements and nontechnical factors to the reduction in consumption. Our analysis suggests that around 20 % of the reductions are likely to be due to thermal retrofits of existing dwellings (insulation and new windows), 31 % due to boiler or heating system replacements, 1 % due to replacement of old dwellings with new, energy-efficient buildings, while some 45–50 % of the savings cannot be explained by these technical improvements. Most of these reductions appear to have occurred in non-upgraded, non-new dwellings. Although we do not know what caused these reductions, the finding is robust to very wide inaccuracies in figures for savings through technical improvements in buildings’ energy efficiency. More research is needed to explore the extent to which this implies increasing fuel poverty, increasing skills and motivation among non-poor households to heat more economically, or the effects of demographic and lifestyle changes. Highlights ? German home heating energy consumption fell by 105 TWh in 2000–2011 ? Approximately 31 % of this was due to boiler/heating system upgrades ? Approximately 20 % was due to window replacement and thermal envelope upgrade ? Less than 1 % was due to replacement of old with new stock ? Over 45 % cannot be explained by technical upgrade factors ? This could imply rising fuel poverty or more skilful heating behaviour