In 2018, the Dutch Naturefriends decided to meet the strict criteria for the Green Key Eco Label with all their houses. Supported by the Technical University Delft, the energy consumption was reduced considerably. Since 2012, electricity consumption has fallen by 35 % thanks to the use of more efficient refrigerators, LED lighting, solar modules and CHP systems.  

Reducing gas consumption was more difficult. For the insulation of roofs, windows and circulation pipes large investments were required and proved to be successful: consumption has fallen by 18 % since 2012. By purchasing CO2 certificates, the Naturefriends contribute to the reduction of CO2-emissions. A huge success is the Naturefriends House De Banjaert, which by now has been turned into an almost energy-neutral accommodation. 

An energy-conscious management of the Houses is the basis for the successful implementation of the Green Key, which is supported by an ongoing exchange of knowledge. The support of our guests is also important – motivating stickers with slogans like "windows open, heating off" motivate visitors to contribute to energy savings.