Zecc Architecten and the Oneplanetarchitecture institute (OPAi) of Thomas Rau not only renovated a monumental villa in Driebergen but also turned it into the first energy-neutral monument in the Netherlands. Zecc has now won the North-West/Central regional prize for the BNA Building of the Year. Architectural studio RAU was commissioned by OPAi to develop the energy concept for this energy-neutral monument.
The brief was to renovate the villa while retaining its monumental qualities. All the work which has been carried out on the building is reversible, and can be undone without leaving any traces behind on the historical structure.
It was a challenge for us to achieve a high energy performance while adhering to the conditions of this brief. Especially when you think that most new buildings today – where this level of ambition would be far easier to realise – are far from energy-neutral. Thomas Rau
The energy-related measures are not visible from the street. Behind the front and the side façades, a second skin has been installed, including secondary windows fitted on the inside. The combination of original windows and secondary windows fitted on the inside is used to ventilate the building naturally and, by so doing, to create a healthy and pleasant indoor climate. The outside air enters the cavity between the old and new skin via the underside of the original windows. There the cold air is preheated and slowly rises. The heated air from the cavity then enters the living space via hidden grilles above the secondary windows. The outlet air is discharged centrally via the bathroom. Choosing this solution has meant that the amount of pipework needed has been reduced considerably, and the monumental character of the dwelling has not been affected. The only place where the second skin is applied on top of the original façade is on the rear façade. This façade is not used to ventilate the building.
To insulate the villa, natural materials have been used as much as possible. The internal walls have been insulated using wood fibre board and finished with mud plaster, while the roof space is insulated using flax insulation. The crawl space below the ground floor is filled with non-toxic granulated recycled glass.
The building is heated by means of wall heating and in some areas by means of underfloor heating. The heating elements are connected to a buffer tank in which hot water is stored. This buffer tank is fed from two different heat sources. The solar energy collected by solar collectors on the roof is used to heat the water. This system will cover most of the building’s hot water requirement. The heat for heating the building is generated by means of a ground heat exchanger in conjunction with a heat pump. This means that in the winter, the natural heat from the ground can be used to heat the building. The energy required for the heat pump will be produced by solar cells on the roof.
The combination of inventive insulation and sustainable generation of energy has enabled the construction of perhaps the first energy-neutral monument in the Netherlands, while retaining its monumental structure. For more information on the architectural design and the interior of the villa, please visit the website of Zecc Architecten. For more information on the construction process, please visit the website of the clients.