The advantages of Active Houses are not limited to new constructions. A social housing area in the Netherlands shows how the principles can be applied to existing buildings – to the great delight of the residents.

Renovation based on Active House principles is an opportunity to add extra value to housing stock and prolong the life of existing buildings.

With half the current European building stock dating back to between 1945 and 1980, renovation is an issue of increasing urgency -and becoming a more attractive option than demolition. In the Netherlands, as elsewhere in Europe, many buildings are worn out and lagging behind the standards of comfort and indoor climate newbuilds can offer. But in 2012, GroenWest, a housing association in the Netherlands, decided to do something about it.

In the Poorterstraat district of Montfoort, a social housing area, GroenWest owned 92 single-family houses that had provided affordable homes for local families since the 1970s.

However, after almost 40 years, the houses had become worn and uncomfortable by 21st century standards. The shortcomings included draughty, gloomy interiors, soaring energy costs and a general lack of space.

GroenWest teamed up with the VELUX Group for a major renovation that would transform ten three-storey, 131 m2 homes into buildings that produce energy, offer excellent living conditions and provide maximum daylight. In other words − Active Houses.

The architects from BouwhulpGroep first added extra space and light by bringing the houses’ unutilised attics to life. Every attic was enlarged and became an entity of its own, resulting in a new room and a rooftop terrace, alongside a central stairwell with roof windows for improved distribution of daylight and fresh air. The ground floor, first floor and staircase were also remodelled to ensure that the daylight and air from above benefitted the entire house.

Peter Korzelius, former Chief Executive of GroenWest, has seen for himself how the improved light conditions are literally enlarging the living space of the Porterstraat residents:

"They are very happy that the rooms can be used for all sorts of purposes, thanks to the amount of daylight. Before the remodelling, the attic was just a dark storage room," Korzelius recalls.

The renovated homes ensure proper ventilation in several ways. Facade and automatically operated roof windows are strategically positioned on all floors, from the ground level right up to the roof.

On the one hand, they provide horizontal cross-ventilation on the different floors; on the other, opening the roof windows on the top floor creates a vertical chimney effect around the open stairwell that channels stale air up from the lower floors and allows it to escape through the roof.

Daylight, fresh air and a more stable indoor climate are qualities highly appreciated by the residents in Porterstraat. In the words of Edwin Hamelink, Poorterstraat resident for two decades: