In general, I am well equipped against temperature extremes, as my house is built do "quasi zero energy" standards, with 36 cm thick walls in three layers and triple glazing on the windows. But after several days with daily temperatures in the mid-30s Celsius (up to 100°F), and not much cooling during the night, the rooms in my house are around 27°C (80°F) and it's getting uncomfortable.

The obvious solution, as all my American readers will immediately say, is air conditioning. A few years ago, when heat waves went from being very rare to occurring occasionally, I bought a good quality mobile air conditioning unit. It is a monoblock unit on wheels with 12,000 BTU of cooling power. At the start of the current heat wave it still managed to cool down our bedroom to 20°C before we went to bed. Enough to turn it off, fall asleep, and not get too hot by the end of the night. Right now that air conditioner is struggling. The problem is that you need to open the window to put the vent hose outside; and as much as I'm trying to seal the window around that hose, at 36°C outside I can't get the inside much cooler than 24°C. Which is an improvement to the 27°C before, but not a huge one. And if I cool my bedroom to 24°C, it gets too warm to sleep during the course of the night.

So I am considering adopting American habits and installing a fixed split air conditioner. Which might be expensive and difficult due to those thick insulated walls. In any case, while my monoblock air conditioner cost several hundred bucks, a fixed unit will be several thousand bucks with installation. On the positive side, a fixed unit with the vent going through the wall means that I wouldn't have to open the window to run the air conditioning, and I could achieve a higher difference between inside and outside temperature. In a situation where 40°C becomes possible in Belgium (the current heat record is 39.9°C) and heat waves are becoming more frequent, more intense, and longer, this investment might become necessary.