News

monitoring in Hannover

As part of the act2 project, a total of 52 buildings in Hannover (with 373 dwelling units and around 24,000 m² of living space, for the most part owned by two housing-development companies) underwent energy efficiency refurbishment. In all cases, full refurbishment was (or will be) carried out while the dwellings were occupied. With an insulation thickness of 14-16 cm for the outer walls and 20 cm for the top-floor ceilings, the statutory requirements for new buildings were either met or exceeded. To complement these insulation measures, conversion to environmentally friendly heating systems (district heating and pellet heating) took place. The consumption data analysed to date - covering either two or three heating seasons - indicate heat energy savings that, at 50-70 per cent, are far higher than those for buildings refurbished in the usual way. It proved possible to reduce consumption from more than 140 kWh/m²a down to 45-70 kWh/m²a. Monitoring outcomes for other properties, including those of private house-builders, will be available in the autumn.