• German Federal Foreign Office

German Federal Foreign Office, Berlin, Germany

In 2011, the German Federal Foreign Office extensively modernised the technical systems used in its buildings, the first Federal Ministry to do so as part of a government energy performance contracting policy. This enables the Ministry not only to cut energy costs by more than a quarter per year, but also to save about 1,800 tons of CO2, thus playing an important role in achieving the German government's climate protection goals.

Caverion ensures that the Foreign Office is equipped with the latest building systems at no additional cost to the federal budget. Although the preparations involved considerable effort and some things did not go quite to plan at the start, over time processes have settled down to run smoothly. Now we save both energy and costs and are regarded as an innovative exemplary role model for other public buildings".
Ingo Dreßen, Deputy Head of Internal Services

Service Areas

  • Managed Services


  • Cooling
  • Ventilation & Air Conditioning
  • Heating & Sanitation

Client Segments

  • Public - Buildings


  • Office


Further optimisation of an already energy-efficient building through energy performance contracting. 


In a move designed to minimise energy costs at the Federal Foreign Office, Caverion implemented efficiency measures in all areas of building technology.

Ventilation and air conditioning systems
Caverion improved the efficiency of ventilation and air conditioning systems by installing frequency converters and replacing fan drives. 

One of the special features is the solar air collector system installed on the roof of the new building for pre-heating the outside air, which has even succeeded in using renewable energies, something quite unusual in energy performance contracting.

Measuring approximately 200 m², the system enables fresh outside air to be pre-heated by the sun without the use of fuel: the outside air passes through the solar collector, where it is heated. This pre-heated outside air is then fed into the ventilation systems. This relieves some of the burden on the heating system. In summer, the air is diverted around the collector. This avoids unnecessary cooling.

A highly efficient compression refrigeration machine was used for the air conditioning system. One of two existing absorption refrigeration machines has been retained. An optimised control concept is used to save energy when operating the refrigeration technology. In addition, pumps were replaced and the hydraulics were adjusted.

An innovative LED lighting system was installed in the underground car park, the bicycle storage rooms and in the basement corridors. Daylight and motion sensor control ensures that the lights only come on when they are actually needed.

Individual room controls were fitted to the radiators in about 850 offices. This makes it possible to maintain the room temperature as needed or to lower it when the room is unoccupied. The heating system has been further optimised by replacing the pumps and adjusting the hydraulics.

Further actions
Installation of electricity, water and heat meters for extended energy monitoring.

Water saving fittings and waterless urinals are installed in heavily frequented areas
A reverse osmosis system has been installed for the cooling towers.

2011 - 2021

Key project figures
● Area: 177,000 m² gross floor area
● Previous energy costs: EUR 1.95 million per year
● Guaranteed savings: EUR 604,000 per year (31.1 percent)
● Investment: EUR 3.0 million
● Construction cost subsidy: EUR 1.2 million
● Budgetary savings: EUR 317,000 per year
● CO2 reduction: 1,780 tonnes per year (22.6 percent)
● Warranty phase: September 2011 - August 2021

Facts and figures on Caverion’s role
Caverion guarantees the Ministry an annual energy cost savings of 31 percent. The measures were implemented in 2011.The warranty phase in which the contractor is required to guarantee the projected cost savings has been running since then. Caverion will maintain and further optimise the systems for ten years.

In a move designed to minimise energy costs at the Federal Foreign Office, the contractor implemented efficiency measures in all areas of building technology.

Guaranteed savings: EUR 604,000 / year (31,1%)

CO2 reduction 1,780 tons / year (22,6%)

Warranty phase over 10 years