Villa Sanseveria

An old house from the 60s is transformed into a NZEB holiday home leading to a 96 % reduction in energy use

Building with nearly zero energy (NZEB) principles will be mandatory in Belgium from 2021 on. With one eye on the future, choosing NZEB today is a smart move. But is it also for renovations?

Refurb project member Christophe Debrabander from Bostoen has taken an interesting project to transform a very energy inefficient house from the ’60s to “Villa Sanseveria”, a NZEB holiday home. The initial situation was as follows: single glass, no insulation, ancient heating and sanitation and an airtightness of over 12 volumes per hour. But there is potential: the house has an interesting geometry with an almost square floorplan and gable roof.

Through a series of measurements, the house is being upgraded from an 875 kWh per m² energy gobbling dwelling to an airtight and well insulated vacation home with an energy use of only 35 kWh/m² (a reduction of 96%!). The trias energetica is our guide here. First we tackle the insulation, airtightness and ventilation. After those measurements which lower the energy need drastically, we look for ways to generate energy in a sustainable way, in this case with a combination of a geothermal heat pump and photovoltaic panels. Only after these two measures, we look for traditional ways to heat the house. In this case, additional measures are not necessary.

One thing that we have to keep in mind after all these energy saving measures, is the chance of overheating. The geometry of the building, in combination with a small glass surface (typical for houses of this era) makes sure we score well in this category.

So NZEB for existing buildings is possible but a thorough masterplan is needed before getting started.

You can experience this house as a holiday in the Flemish Ardennes.