Power efficiency classes for households

In the project, researchers from ISOE and the German Öko-Institut are developing new approaches to reduce power consumption in households. The new “power efficiency classes” label will be recording power consumption in households and assigning them an efficiency class.

Research approach

To date there have only been power efficiency classes for individual appliances such as washing machines. However, these labels supply no information about how much power is actually being consumed when an appliance is in use. The total power consumption of a household is also an unknown entity – for example per day, week or year, depending on behaviour patterns. This is the project’s starting point, with the goal of developing an indicator for households so that they can more easily estimate their total power consumption and better implement specific goals for saving power. Power efficiency classes for households might include classes A–F like the power label of the European Union. It is based on the annual power consumption of a household, extended by attributes like household size.

Developing power efficiency classes

Researchers’ initial step is to assess the technical and user-related potential for saving power in households. In addition to the number of people living in a household, expected socio-demographic developments are factored into the calculations, i.e. the trend towards smaller households. Technical innovations – e.g. integrated appliances that replace several old appliances – and changing user behaviour, for example due to increased electronic control and automation of building technology, are also taken into account. The collaborative research team uses this data to define limits for power efficiency classes distinguishing between power consumption that seems necessary from today’s perspective, and excessive consumption. On this basis, the project team develops a “power efficiency classes” label that pools the total power consumption of a household and assigns it a consumption class. A labelling process for particularly frugal housholds that is harmonised with this procedure makes things simple and transparent and thus increases the motivation to attain a better power efficiency class.

Target group analysis, technical innovations and power saving packages

For different target groups, the researchers show up new ways of attaining a better power efficiency class and develop corresponding consulting offerings. The assumption is that young households, for example – that have just been founded – have other opportunities and limitations than established households with a very low income. At the same time and in close cooperation with corporate partners, the research collaboration is setting up integrated technical solutions and possible new market offerings that are geared towards the needs of the target groups. The results are integrated socio-technical power saving packages which offer different users a pragmatic gateway into saving power.

Field test and representative survey

The project partners test the power efficiency classes and corresponding power saving packages in selected households in cooperation with the participating power companies. In a field test, they evaluate the households’ sensitisation for their own power consumption and the suitability for everyday use of the various power saving packages. From the results gained, the researchers develop an optimised version of the total approach whose acceptance is tested with the help of a representative survey with an integrated conjoint-analysis. Afterwards, the team extrapolates power saving potential and transformation effects that can be attained across Germany.


Reducing power consumption is a vital building block for transforming the energy system. The research team is studying how power consumption in households can be sustainably reduced and stabilised over the long term. Simple and customised solutions are therefore necessary, which make power consumption visible, but don’t make daily life more complicated. With the help of new offerings, power companies and manufacturers of appliances will be instrumental in making this happen. ISOE is leading the collaborative project.

Project partner

  • Öko-Institut e.V.

Corporate partners

  • BSH Hausgeräte GmbH
  • ENTEGA Privatkunden GmbH & Co. KG – a company belonging to HEAG Südhessische Energie AG (HSE)
  • Badenova AG & Co. KG
  • Verbraucherzentrale NRW e.V.
  • co2online gGmbH
  • OSRAM GmbH


The German Federal Ministry of Education and Research (BMBF) is funding the project “Power efficiency classes for households. Supporting power-saving innovations in households, market and appliance technology” within the social-ecological research funding priority. (Funding code: 01UN1215)


Stieß, Immanuel/Corinna Fischer (2016): Bewerten, Beraten, Begleiten - Stromeffizienzklassen für Haushalte. Frankfurt am Main: ISOE - Institut für sozial-ökologische Forschung


2013/04 – 2016/07