The heating season is over and barely a month later, large amounts of energy are already being used in the Netherlands to achieve the opposite: cooling houses, and especially office buildings. This is due to design errors in buildings in the Netherlands, experts tell NU.nl. But there is a simple solution: the classic sun protection. How do we get it back on the streets?
As our summers get hotter, building cooling is becoming an increasing problem. Not only because this is important for people’s comfort and health, but also because of the rapidly increasing energy consumption of the growing number of air conditioners.
And that while the most important cooling measure is cheap, energy-efficient and has been available for years, but is often skipped: the sun protection.
“Keeping out the sun is the most important measure to keep homes and offices cool”, says Jeroen Kluck, lecturer Climate-proof Urban Design at the Amsterdam University of Applied Sciences.
Angled awnings are most effective
This is also the opinion of researcher Lisette Klok of the same research group, who thinks that there are fewer sun protection devices nowadays than in the past. “I just don’t see them in the streets anymore. I don’t know what happened there. Landlords don’t put them on homes as standard either.”
Kluck and Klok mean the classic sun blinds, which come down diagonally from the outer wall with a windmill like a canopy.
“If you want to keep your house cool, they are also more effective than the vertical screens that you see against windows nowadays,” says Andy van den Dobbelsteen, professor of Climate Design at TU Delft. “Sliding screens remove all light, and heat builds up behind that screen. I don’t think that’s a smart design.”
Offices have (too) tight facades with many windows
He thinks there are also design flaws in Dutch homes and offices. They have all maximized the window area.
“And if you want to hang blinds on such a mirrored facade, you get into a fight with the architect, who wants everything as sleek as possible. So we become addicted to air conditioning, which is turned on in April in many offices.”
In order to break through this, Van den Dobbelsteen previously suggested making sunblinds mandatory in new buildings. Because even well-insulated new-build houses can become ovens in the summer when they are baking in full sun.
‘Air conditioning without sun protection should not be possible’
Cooling with an air conditioner or heat pump also appears to be a practical solution for cooling homes, but that comes with a price, for the environment and the wallet: sky-high energy consumption.
“Solar radiation is so intense,” says Van den Dobbelsteen. “In full sun, about 1,000 watts of energy enters your house per square meter of window. With air conditioning, all of that has to be ‘cooled away’. All of this costs energy, unless you manage to keep that energy outside.”
Klok also sees little point in people trying to compensate for the full sun with electric cooling. “I sometimes think: it should be prohibited for houses to have air conditioning on the facade or roof, if they have not installed sun protection first.”
Lessons from Southern Europe: shutters and overhangs
According to Van den Dobbelsteen, which solution is most suitable also depends on the orientation of the walls. In addition to folding sun protection, so-called overhangs are also effective on south walls.
These are large overhanging eaves, which provide a lot of shade at high sun positions in the summer. “You also see those overhanging roofs in old houses in warmer climates in southern Europe, which often have small windows with shutters on the outside.”
“But on east and west walls, the sun often enters at a low angle in the morning and evening. An overhang does little to prevent that and a roller screen can be effective again.”
A tree can (eventually) be a sun protection
Is there anything else to do? “Ventilation only comes in after the sun has been blocked,” says Kluck. “During the summer heat, this is of course necessary, especially when it is relatively cool outside, so at night and in the morning.”
And as a third measure, trees can also have a cooling effect, says Klok. “Or, for example, espaliers, because they can cast a shadow on windows and walls.”
Finally, she has an idea to get sun protection back into the street. “We should have held a design competition. Maybe blinds have gone out of fashion and we have come to find them ugly. But there is undoubtedly something creative to come up with.”