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Saving energy in new and old buildings

Energy-efficient buildings are important if the energy transition is to succeed While energy-efficient building became standard practice some time ago, the energy-efficient refurbishment of older

buildings is till lagging behind. dena provides a broad range of information services to support homeowners in the implementation of energy-efficient refurbishment.

Energy transition for buildings

Energy-efficient refurbishment

Energy-efficient refurbishment has many benefits for private homeowners. Moreover, increasing the energy efficiency of older buildings is a crucial factor in reaching the climate targets.

A building’s energy efficiency is a crucial factor in the construction of new builds or the refurbishment of older buildings. The German Energy Saving Ordinance (EnEV) and the Renewable Energies Heat Act (EEWärmeG) define many different energy standards that investors must adhere to in the construction of new builds.

Refurbishment offers significant potential

On the other hand, there are approximately 18 million existing residential buildings. Around three quarters of them were constructed before the First Thermal Insulation Ordinance was introduced in 1979. The majority of older buildings are unable to fulfil current energy standards. Efficiency potential is particularly high in these buildings, as the energy consumption in older buildings is frequently up to five times higher than in modern efficient houses.

This makes it particularly important to refurbish older buildings if the energy transition targets are to be reached. Above all, building owners must receive information and targeted funding in order to motivate them to carry out energy-efficient refurbishment. dena becomes involved at this point: among other things, it provides information on the benefits and opportunities of energy-efficient refurbishment.

The benefits of modern insulation, windows, heating and ventilation

Energy-efficiency measures achieve more than just reducing the energy costs. An efficiently heated house without draughty corners also provides a more pleasant living environment. The measures involved in energy-efficient refurbishment include the insulation of outside walls, the roof and the cellar, replacing windows (thermally insulated glass) and efficient heating systems for heating and hot water. It is also worth considering the use of renewable energies. Modern ventilation systems contribute to an improved room climate while filtering dust and pollen out of the air.

Competent advice on energy

Not all measures need to be carried out at once, of course. It is perfectly reasonable to complete refurbishments step by step. After all, there is no standard solution which can be applied to all buildings. Each house is unique and needs to be considered individually. Competent advice and good planning by an expert are important in order to guarantee the quality and cost effectiveness of the measures.

A detailed energy-efficiency analysis is conducted during qualified on-site advice on energy. A professional energy consultant reviews the requirements, recommends  suitable measures that suit the specific building, and provides an initial overview of eligible funding programmes. Qualified energy consultants are listed in the Energy Efficiency Expert database.

What the government does to support the energy transition in the building sector

The government subsidises energy-efficient building and refurbishment, for instance through KfW and the Federal Office for Economic Affairs and Export Control (BAFA).

Projects on the topic

Database of Energy Efficiency Experts for Government Funding Programmes

Investors can consult the Database of Energy Efficiency Experts for Government Funding Programmes to find experts in the area of energy-efficient building and refurbishment.


  • Project start 2011
  • Source of funding: BMWK, KfW Bankengruppe, BAFA
  • Number of listed experts: over 18,000 and about 16,000 available online
  • Number of network partners: 23

Campaign “zukunft haus” (“future house”).

What was originally conceived of as a portal for informing and motivating owners in 2003 has now developed into an extensive campaign and a mainstay for stakeholders from the industry and politicians, as well as for the press.


  • Project start: 2003
  • Over 9,000 newsletter subscribers
  • Approx. 30,000 press reports with a total reach (circulation) of 1.2 billion
  • Turnover of more than 6.3 million information brochures
  • Free hotline: over 100,000 questions on energy efficiency in buildings
  • Website: (consumer) information tailored specifically for a particular target group; over 8 million visitors on central internet platform

Model project for efficient houses

In dena’s ‘Model Project for Efficient Houses’, residential buildings have been being renovated to a high level of energy efficiency since 2003, and the same has been being done with municipal buildings, including mainly schools, since 2007.


  • Project term: 2003 – 2014
  • More than 400 residential and non-residential buildings throughout Germany renovated and assessed for energy efficiency
  • More than 300,000 m2 of living space refurbished
  • CO2 savings of over 3.7 million tonnes per year for residential buildings
  • Final energy consumption in the model projects reduced by an average of 80 per cent

"The Building Transition" Refurbishment Campaign

“The Building Transition” is the first nationwide, cross-sectoral refurbishment campaign. The campaign provides owners of detached and semi-detached houses with detailed information on all aspects of energy-efficient modernisation, and helps them locate qualified energy experts.


  • Campaign start: 2014
  • Number of partners: 24
  • Number of sponsors: 2
  • Number of regional cooperation partners: 16
  • Regional information events for homeowners: approx. 330
  • media reports triggered by the campaign: approx. 1,600
  • social medial reach: roughly 800,000 persons