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Computational example

We would like to point out to you that lower operating costs and less negative environmental impact can be compatible with savings of investment costs. The example concerns an administration building of Kaufhof AG, which was redeveloped in 1997 with our help. A conventional air-conditioning unit was able to be saved on, owing to our consultation.

Instead, we have computed natural ventilation in connection with an exposure of concrete thermal mass and have implemented this. An improvement of the heat insulation, an illumination controller and a high-quality solar protection led to the desired success. The building simulation had demonstrated that the climate comfort level complies with all requirements, even without the need for an air-conditioning unit.

Climate concept

Mit Hilfe der Computersimulation können wir eine konventionelle Planung optimieren. Die empfohlenen Maßnahmen verbessern das Gebäudeklima und mindern die Invest- und Betriebskosten.

  • Windows Standard
  • Mechanical ventilation
  • Air-conditioning unit
  • Lighting Standard
IPJ- optimised
  • Windows with adjustable outside awnings
  • Natural ventilation particularly during summer nights
  • Comfortable climate, achieved with natural ventilation
  • Switching off the lights on sunny days

Investment costs

The budget of the client for the construction project had to be kept to, strictly so. The components suggested by us were able to still considerably reduce the investment costs.

  • Air-conditioning unit
  • 300.000 EUR
  • Awnings and light sensors
  • 80.000 EUR
220,000 euros of investment costs were saved!

Energy consumption and energy costs

The energy consumption and the consumption costs caused thereby can be very exactly forecast by means of the building simulation. Our approach was compared with the conventional approach on a building simulation model.


445.000 kWh/year

39.000 EUR/year


850.000 kWh/year

25.500 EUR/year


270.000 kWh/year

11.000 EUR/year


75.500 EUR/year


235.000 kWh/year

21.000 EUR/year


650.000 kWh/year

19.500 EUR/year


0 Wh/year

0 EUR/year

Sum total

40.500 EUR/year

Energy conservation

If one knows the consumption of heat, cold and electricity, the total energy consumption can be calculated with primary energy performance indicators. Since 2002, this approach is also a component of the Energy Saving Ordinance EnEV.

  • 2.725.000 kWh/year
  • 1.355.000 kWh/year
The savings amounts to 1.370.000 kWh of primary energy per year.
This corresponds to the annual energy consumption (electricity and heat) of 45 households with 3 people each!

Resource consumption: (in kWh PE/ year; PE = primary energy)

Cost savings

An environmentally friendly technology concept saves on both investment and operating costs. The savings result from reduced or no longer applicable operating costs, capital costs and maintenance costs.

  • 123.500 EUR/year
  • 52.500 EUR/year
You save 70,000 euros of operating costs and maintenance costs per year!

CO2- savings

The negative environmental impact from the building was halved. The desired environmentally relevant is shown here with the help of the CO2 equivalent.

  • 818 tonnes CO2/year
  • 407 tonnes CO2/year
The savings amount to 411 tonnes of CO2 per year!