In theory we will get a storm this afternoon and I am impatient for it. I am impatient for heavy rain to cool the roof and walls of this nightmare minergie building. As great as it is to have a cheap building to heat in winter, it is a deadly building in summer, especially when neighbours open their windows to aerate and let hot air in.
In normal buildings, if you open windows you get a draft, and that draft circulates air and it’s refreshing, and when you close windows that freshness lingers. In a minergie building, if you leave the window blinds open the sun heats every surface, and the air. The space heats up just like a car.
I noticed that a Northerner is here this week and has the windows wide open, allowing sunlight to heat the dark tiles. The result is that neighbour is superheating his own apartment, and my own.
The temperature went from 29.7 to 30.2°c That’s half a degree, which is nothing, but it’s in the opposite direction than I expected for today.
The outside air temperature is 22°c so it is absurd that the apartment would be warming rather than cooling. The only logical explanation is that the neighbour next door, by opening his balcony door, and keeping the curtains open, has ensured that his apartment is behaving like a car left in the sun, and he is now superheating his apartment, and by connection mine.
The shutters are now closed again so in theory, things will improve during the thunderstorm expected this evening. That thunderstorm will be welcome. I really want this building to purge some of its heat.
The Positive Feedback Loop
The bedrooms, at the highest point in the building are now at 32°c and this will continue until the end of summer, unless it rains heavily. When I open windows to let fresh air in, it is undone by the building within half an hour or less. This means that for months I am sleeping in a 32°c environment.
If I was in Rome, in the middle of summer and the OAT was 40°c I’d accept it, but we’re not in Rome in summer with an OAt of 40°c. We’re in Switzerland with an OAT of 22°c with a bedroom that is ten degrees warmer than outside, and attempts to cool down the bedroom are undone within half an hour of closing windows.
Mosquito Nets and Rain
In my experience the best solutions to fight the heat are mosquito nets and rain. With mosquito nets you can open windows for the entire night, without worrying about mosquitos. With rain roof tiles, veluxes and walls are cooled from the outside in, and evaporation speeds up the cooling process. As long as there is real rain, rather than just a sprinkle.
The Simplest Solution
Usually during a heatwave my favourite thing to do is to open windows, or doors, to create a draft, to allow pressure differentials to move air around because that movement of air cools us down. In air conditioned, and minergie buildings, we can’t open windows. With air conditioned buildings it’s because of a loss of efficiency, and with Minergie buildings it is because the walls and surfaces absorb heat, and minergie then radiates it out, as soon as you close windows.
That’s why mosquito nets, and rain are idea. Rain cools the building, and mosquito nets allow hot air to escape the building, rather than trapping it.
It’s worth highlighting that we’re in a drought, and that there is now a high risk of forest fires. We need rain to cool buildings, but also to provide plants and animals with relief.
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