A window unit is not going to cool my whole house.
Aren't window units designed for sliding windows?
No one has those in my country, or at least not in the last 60 years.
Forty years ago, a normal average summer temperature in the Netherlands (measured over June, July, and August in De Bilt) was around 16.2°C. A normal afternoon temperature during the summer months at that time fluctuated between 20°C and 22°C. Sometimes, people had to turn on the central heating, on cold days in the middle of summer.
We never needed air conditioning in my country. Just like people in Hawaii or Aruba don't have a central heating system or underfloor heating, which is almost standard in my country, we never had a need for air conditioning. Even when my house was built, 17 years ago, the climate was still not changing as much as it doing now.
You don't spend thousands of dollars/euros on a system that you use a few days per year. We do still have some high temperature records from decades ago, but those are from extremely fluke weather, that only lasted one or two days back then. And when that happened, people were completely ill prepared and many people died, just like that one freezing weather period in Texas, in Februari 2021. No one in my country would die in their own home in cold weather like that, because our houses are built to withstand cold, not heat.
Why would I then spend thousands of dollars/euros on a complete system? Because they are also useful for heating a home on electricity. For several months in the spring and fall, it's still cold enough to need heating, while there is enough sun coming from my solar panels.