The refurbished townhouse in Dresden has been given a new lease of life following a comprehensive refurbishment based on the Energiesprong principle. The project began with a historic block of flats whose energy performance, prior to modernisation, showed a primary energy demand of 241 kWh/m²a. Through the implementation of a high-performance energy and refurbishment concept, this demand was reduced to just 12.6 kWh/m²a – a figure normally only achieved in passive houses. At the same time, the living space was expanded from 410 m² to 687 m² by adding an extra storey, which also raised the building’s classification under planning regulations. The aim of the Energiesprong approach is a refurbishment that combines high living comfort, short construction times and maximum energy efficiency. The measures – including structural thermal insulation from the inside and a timber-frame extension – were implemented in a resource-efficient manner. A scientific monitoring system continuously collects data on energy generation and consumption. Tenants benefit from higher quality and comfort whilst their rent, inclusive of heating, remains unchanged.
Project description
The refurbishment utilises the innovative Erifol system, which integrates both structural thermal insulation and heating technology. Reflective films installed behind the radiators utilise radiant heat rather than convective heat transfer, enabling heating via low-temperature surfaces with a maximum surface temperature of 26 °C. Between the films, insulating layers of air provide effective insulation equivalent to approximately 80 cm of conventional wall insulation, whilst the material itself is only 10–20 mm thick. Central to the heating supply is a combination of geothermal energy and highly efficient surface temperature control. A geothermal system extracts environmental heat from the ground and uses heat pump technology to provide heating; in summer, the system can also be used for cooling. This is supplemented by an internal thermal insulation and temperature control system using capillary tube mats, which operates at low flow temperatures and is therefore particularly energy-efficient. The electricity required is generated by a large-scale photovoltaic system on the building itself, meaning that a large proportion of the operational energy is provided on-site from renewable sources. The measures – including structural thermal insulation from the inside and a timber-frame extension – were implemented in a resource-efficient manner, and a scientific monitoring system continuously collects data on energy generation and consumption. Tenants benefit from higher quality and comfort whilst the rent remains fixed.