Energy-efficient construction

Energy saving – Energy efficiency – Sustainability

National and European laws on energy saving that apply to buildings (e.g. the German Energy Conservation Act (EnEV) and the Energy Performance of Buildings Directive (EPBD) are becoming even more stringent in light of climate change. Legislators are striving to attain a steady decrease in energy consumption when it comes to the operation of buildings.

The amount of achievable comfort of use is being pushed to centre stage due to ever decreasing energy input. Since 2007, it has been possible to make objective assessments of the indoor air quality of a building in light of the European regulatory provisions EN 15251; this assessment became necessary because only the relationship between comfort of use and energy input allows a statement to be made concerning a building's energy efficiency.

The building sustainability not only embraces energy efficiency, it is the subject of holistic considerations, and includes things such as life cycle, ecology, economy, function, and technology, among other things. Based on a sharp rise in demand, building sustainability has since come to include conscientious planning and official certification (e.g. DGNB, LEED, BREEAM) with the objective being to add value, improved value development and increase rentability.

Comfort of use - indoor air quality

Besides thermal comfort, the evaluation of comfort of use according to DIN EN 15251 also encompasses acoustic, visual and air-hygiene comfort within the rooms of a building.


Room climate - indoor qualities
Coziness and comfort - use

4 essential assessment criteria:

At the same time, the individual aspects of comfort are divided into only four categories to enable the transparency of attainable comfort. This is allows for a classification similar to the well-known graduated ratings that are found on items such as refrigerators. The following illustration shows the "Comfort certificate" of an office building with the classification of thermal comfort during the summer months. The percentage data in this example corresponds to the monthly working time.

Consultation on energy efficiency

Our conceptual consulting services for energy efficiency extend beyond advice on energy use, which primarily aims to ascertain the annual consumption for energy as specified in EnEV. Then, in light of improved thermal insulation in a building, thermal comfort in summer is becoming a focus. Proper lighting with natural light, good room acoustics and an adequate supply of fresh air are important aspects with regard to user comfort.

Because of the complex interaction between the individual specialist areas, innovative planning tools are necessary for the development of energy-efficient air-conditioning concepts, which can be only illustrated to a limited extent using standard methods of building physics and technical systems planning. Therefore, as part of our integrated consulting service, a multitude of computer-based simulation techniques are employed (e.g. thermal simulations, daylight simulations, spectral calculations for determining the characteristic values of façades, ventilation simulations, simulations of air humidity in rooms, simulations of indoor air CO2 concentration, thermal bridge calculations, etc.).

  • Thermal simulations
  • Daylight simulations
  • Spectral calculations to determine the facade characteristics
  • Ventilation simulations
  • Simulations on the interior humidity
  • Simulations on the carbon dioxide concentration of the indoor air
  • Heat bridge calculations

Advantages for the client and user

The prioritisation of energy efficiency in the design process makes it possible to build high quality buildings with reduced total energy consumption. This results in low operating costs for the building throughout the building’s entire useful life. These buildings therefore offer optimum cost effectiveness when considering its overall life cycle and with that comes good marketability and sustainability, which is further enhanced by a high degree of user comfort, and long-term intrinsic value that offers investors a good return.

In addition to such economic and functional advantages, energy-efficient buildings make an important contribution to climate protection, and the minimised environmental impact helps fulfil ecological objectives as well. This increases the market value of the property, especially when it comes to business use, given that a growing number of companies are developing their own carbon neutrality strategy, and are able to better fulfil their corporate social responsibility in this way.

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