It’s time to shine a light on an old technique: shutters. (No, I’m not following in the footsteps of Lowtech Magazine, but sometimes our paths cross).
Shutters are as old as building itself, even predating the invention of glass. There was no glass back then, so how do you keep the warmth in? With shutters. Or, conversely, how do you keep the warmth out? Shutters.
However, this is tricky during the day because you also want some light in a home that still has no glass windows, and occasionally, fresh air. So, it’s a bit of a hassle, opening and closing, adjusting it a bit here and there. Until glass is discovered, and even better: a way to process it.
But even then, even after the introduction of window glass around the first century CE, shutters were still in use: indeed, to keep the sun out, but also to protect the glass, which was quite expensive in the beginning. And actually, shutters have remained in use for centuries after that. It’s only in the last 100 years that we’ve largely lost them, especially here in Northern Europe.
Glass became better and cheaper, and because energy costs went up, we started using double glazing, and now even triple glazing, with little impact on visibility. But where have the shutters gone? After all, our biggest problem seems to no longer be keeping the warmth inside, but rather keeping it out. Large glass surfaces let in a lot of light and warmth, but also trap infrared radiation inside. You already can see the problems ahead: we’ll solve that technically. No, not with simple measures and sensible behavior. We’re rich, so we’ll throw some technology and products at it. Like air conditioning… We let the warmth in first, then actively cool it down, creating a big environmental burden through energy use and the production of equipment. But where are the shutters? They keep the heat out because they sit on the outside. However, it requires active management, as they need to be opened or closed at the right time. Part of this could, of course, be combined with natural ventilation… That’s how it’s done in Austrian buildings and homes that no longer have heating systems, nor ventilation systems: the CO2 levels are measured, and based on that, shutters next to the windows open automatically for a while.[1].
Shutters then. And not just for cooling, of course. They work even better in winter: after all, we might have double glazing, which is fine for the view and daylight, but in the evening, those two properties no longer apply, and it always cools down further at night—it gets much colder. With shutters, you can compensate for that, which makes a huge difference. It’s a win-win. Of course, they should be manually operated; we’re not going to throw more technology at that—people still have to do something, right?
Now, why don’t we use shutters? No idea. I can’t find any research either on whether they’re useful or not , in combination with double glass or else. (regarding operational and embodied energy)
You’d think that when it comes to cooling, we see the benefits every vacation: in hotels and cottages in France and Spain, for example, shutters are still almost standard.
And to think that one of the first energy-efficient projects in the Netherlands, when it was clear that energy would become a problem, used shutters! It was the councilor of the municipality of Schiedam, Chris Zijdeveld, who, together with architect Jon Kristinsson, designed and built the first passive houses in the Netherlands back in the 1980s. Back then, they weren’t called passive houses yet, but they were ahead of their time, and those homes already had shutters!*
These so-called ‘minimum energy homes’ were groundbreaking at the time. They were the standard to which everyone else should aspire. But that didn’t happen. Unfortunately.
Even the 15 kWh per m² heating standard from the minimum energy homes, , which was later set as standard for passive houses in general and was and is achievable, is not even the norm yet. Let alone those shutters.
Passive houses, even though that term didn’t exist back then, are now getting more attention. What was missing, and still is, even in the passive house movement, is the standard integration of material impact. This has not been integrated into the formal passive house approach and is still barely present in regular construction. Despite numerous initiatives and example projects, the regular construction industry still builds on the archetype of homes already invented by the Romans—lots of brick, concrete, and roof tiles. Yes, construction industry is slow…
What does ‘passive house movement’ itself say? “25 years ago, when Bo Adamson and Wolfgang Feist further developed the Passive House concept, they deliberately excluded material use. The goal was for the methodology to be independent of the type of materials used. They made this choice to prevent the Passive House principle from becoming too niche and not taking off. As a result, a passive house can be built with any desired building materials.”
What they forgot is that materials are also energy… (among other things) and part of the equation. In that regard, passive house is actually behind itself….
That aside, Zijdeveld and Kristinsson in Schiedam were energetically on the right side of things, and it’s unbelievable how sluggish things have gone since then. Those homes were already there in the 80s, and they still make a strong case for passive energy houses**. With shutters! Where have they gone, and where are they most useful?
They weren’t ahead of their time, in Schiedam, they were in their time. And we’re now 40 years behind…
.
.
**Note: In those homes, balanced ventilation with heat recovery was used for the first time. Zijdeveld is still enthusiastic about those first passive houses: ‘The performance of those passive houses was incredibly impressive for that time. The indoor air quality in the homes was extensively measured and turned out to be almost identical to the surrounding outdoor air! Additionally, the homes consumed less than 300 m³ of natural gas per year for space heating. With today’s improved balanced ventilation, those homes would now consume only 150 m³ of gas.’ [2]
.
PS: There is, of course, a variant: plastic roller shutters. Horrible to look at, but they work…
.
PS2: There is ridiculously little available online about those homes in Schiedam, and it doesn’t seem to be well documented anywhere. (see just an old low res picture above) I even searched at Het Nieuwe Instituut and found just one photo of a model… [3]
.
[1] https://www.ronaldrovers.com/building-without-heating-more-material-or-more-installations/
[2] zijdeveld: https://passiefbouwen.nl/publicaties/passief-bouwen-is-veel-meer-dan-een-lage-epc
[3] pres woningen bij het Nieuwe instituut: https://zoeken.nieuweinstituut.nl/nl/objecten/detail/e6f9be5f-acf4-51b7-9ce3-31ace8d3149f
