> Most people do use blinds to keep the sun out but they are on the inside of the glass. That's exactly my point, in Southern Europe blinds are on the outside

> Most people do use blinds to keep the sun out but they are on the inside of the glass. That's exactly my point, in Southern Europe blinds are on the outside of the glass, not inside. Reflective coating and insulating double glass is good but not the same as they're not 100% efficient (with outside blinds, they absorb the heat and insulating glass is very good at keeping conduction at bay). I can come home in the evening and barely notice the difference in temperature from when I left (25C-26C in the morning, 26C-27.5C in the evening, so about 1.5C difference); that's even with 33-36C highs outside. By 5PM it's possible to open blinds because I don't get direct sunlight anymore (my house faces South and East and has other buildings towards west), and I open the windows from 10PM till dawn at 5-6AM.