Summer heat is here – but how ready are Czech buildings?
Record-breaking temperatures are being reported across the country, and Czechs are seeking refuge indoors from the sun. But how much shelter from the heat does the average Czech building actually offer? Danny Bate spoke to Ondřej Šrámek, Director of Corporate Affairs Eastern Europe at Knauf Insulation, to answer this question, and to discuss what people can do to improve the situation.
As Czechia struggles with the current heat, how well prepared would you say is the typical Czech building for a heatwave?
“That really depends on how you define a typical Czech building. If we think of the typical sort of un-renovated single-family home, which was built before the 1990s, that is not a very well prepared building.
“You can see that very clearly if you ever go to any DIY store, once temperatures rise – you see a shopping frenzy for AC units, all these units piled high, people buying them at a huge scale. That tells you that our buildings are not very well prepared for it, and of course the issue is even bigger in cities.
“If you have a standalone single-family home, surrounded by some vegetation, you can be okay, but if you're in a city, you can have anywhere between 2 to 5 °C more than outside of the city. It's called a ‘heat-island effect’, which is caused by the built environment, all the roads, buildings and everything that accumulates heat. That is even more difficult.
“So, in the cities, we have to look also beyond the individual building; we have to look at the whole city. If you have a single-family home building outside of the city, you have more control.”
In terms of styles of architecture or the age of the building, what types of buildings tend to be better and more comfortable during a heat wave?
“It's an interesting question. I think, for a summer heat wave, very old buildings, which have very thick rock-based walls, tend to be quite nice and cool. Just enter any kind of church or medieval building – or very modern buildings that were designed already with heat waves in mind, and are well insulated, well ventilated and cooled. Those also can be nice.
“So I would say those two kinds of buildings, but then we also have to think about winter, right? At some point, winter comes, and then out of those two kinds of buildings, only the modern ones remain nice and warm in winter, whereas the medieval stone buildings are cool in summer, which is great, but they are then cold in winter. That is not so great.”
Let's say that you're a homeowner in a place like Prague, in a city, and you're struggling with the heat. What changes can an individual make to improve their home?
“I think there are two sides to this coin. One side is that, if you really want to solve the issue for good, that means a kind of major renovation. That's something that people should really think about.
“If you really want to solve overheating in summer, I think there are five key things that you need to consider. One is proper insulation; people are sometimes surprised that insulation works the same in winter as it works in summer. It works against cold as well as against heat, so it's the first step.
“Well-functioning windows, ideally triple glazed, and especially with external shading. It's a very important thing that protects your house from excessive solar gains in summer, so that can help you massively. It needs to be external in order to work properly.
“The third thing that can help you is mechanical ventilation with heat recovery. Again, that's a type of technology that works both ways. It helps you to keep your house warm in the winter, but cool in the summer.
“The fourth thing is a heat pump, and again, that's something that can help both ways. It can help keep the house warm in winter and cool in summer because they can work both ways. They can heat as well as cool, especially if they're connected with some solar photovoltaic panels. In summer, you kind of can cool your house for ‘free’, because in summer you have a lot of electricity from your PV panels.
“The fifth point, which we touched on a little bit, is vegetation. It helps massively, and you can also put green elements, green roofs and green facades on your buildings. That is especially important in cities, because those elements can help you fight against the heat-island effect that I mentioned previously.
“So those are the five steps that you can take to solve your problem in the long run, but they demand some planning. They're more systematic.
“There are also some quick fixes that you can do, you know, just to help yourself right now. The first thing would be to really think about shading and closing the windows during the day. Don't ventilate when it's very hot outside. Try to ventilate overnight, and to create some draft through the building. Ventilate when it's cool during the night, and then close the windows over the day, to not allow the heat to enter.
“Then, the last thing that you can do is just go to a swimming pool, an air-conditioned mall or air-conditioned office, like I am doing right now!”
Those sound to me like very good practical tips for individuals. But what changes would you like to see on a much bigger scale, in terms of building practices or indeed legislation from the government?
“The real solution to this is the deep renovation of our neglected buildings. We have had a renovation programme, quite a successful one, in Czechia for fifteen years. It's called Nová Zelená Úsporám (‘New Green Savings’). It's a quite well-known programme. A lot of other countries are trying to take inspiration from it. I think we're in touch with our colleagues in Poland, Slovakia and Romania. This programme helps and directs people toward deep renovation, towards all those five steps that I mentioned previously.
“Really, I think the biggest barrier among people is not so much about money, but about knowing what to do, which steps to take and in what sequence. There is a growing awareness now among people that renovation is a good thing, and saving energy in winter is a good thing. We should add that, yes, saving energy in winter is good, but the same thing applies to summer. It's about indoor air comfort, living conditions and quality of living.
“Renovation ultimately is something that people should think about and the government can support it with the continuation of renovation programmes, just like Nová Zelená Úsporám. So I would appeal to the government to keep working on this programme. It's something we can be proud of in Czechia, and that we can also even export to other countries in Central and Eastern Europe.”
