Man is the limiting factor in refrigeration

A total ventilation concept that uses natural drafts, that's what earned DUCO the public award at BouwBeurs 2025 today. It does not use active cooling. It's really just based on the principle of the open window, but smart.

'We make our homes impermeable these days,' says Edwin Pelkman, project consultant for DUCO. 'Nothing is allowed to escape, we even measure the draft through the wall socket!'That's fine in winter, because then no precious heat escapes, but in summer it's not necessary at all.'Then you need to get the heat out of your house just in time, before the heat goes all the way into the walls. 'But humans are the limiting factor in cooling,' Edwin Pelkman continues. 'We only open a window when we get hot, but by then it's actually too late.'

1100 cubic feet through your home

DUCO's natural ventilation system does provide this. It starts with a rooftop weather station, which determines the best time to ventilate. 'That's when there is a certain temperature difference between the air inside the house and outside,' says Pelkman. At that moment, so-called nigth vents open automatically on the first floor, and upstairs in the house a tumbled window, developed by partner Velux. 'With these you rush 1100 cubic meters of air per hour through the house at an air speed of 2 meters per second. That way you refresh the air in the house about 4 to 5 times an hour, then you have the best effect.' Incidentally, the system can also be closed manually at any time. If you have a party, for example, you might want to have the refreshment start a little later.

Changing the air works so well because of the difference in height, Pelkman explains. 'You can have single-sided ventilation, where the air has to go back out through the hole where it comes in. You can have cross ventilation, with ventilation on both sides of the house, which works better already. But you can't make sure that the air is ventilated everywhere in the house. You can do that with stack ventilation, then you can control the ventilation. The air goes up through the stairwell and sucks the air from the bedrooms through the doors.'

Insect and burglary resistant

Of course, a major disadvantage of an open window is that mosquitoes always come in during the summer. DUCO's nightvents prevent them from getting in, and the vents are also burglar-proof. This is very important because of regulations, says Pelkman. 'But also because you have to keep ventilating even if you're in Turkey for a few weeks.' That, in fact, is the strength of this system. Because it consistently removes the hot air from the house, combined with effective shading, you have a cool buffer for the next day. That way, even in hot summers, the house doesn't get nearly as hot as you're used to.