I noticed something about the temperatures yesterday, so got out some thermometers and checked the situation.
The temperature inside the house was 24 °C, outside was 34°C. The interesting thing was that the temperature of the window glass on the western side of the house was almost 45°C! That was a lot of heat pumping into the house.
I dropped the external blind and after 10 minutes checked the temperature of the glass and it had dropped to 37°C. Half an hour later I checked again and the temp of the window glass was down to 34°C, the same temperature as outside.
This showed me much heat is radiated through uncovered windows in summer. Imagine how much is pumped in through those huge windows in many commercial, or some newer residences. How much power is used by airconditioning to make temperatures comfortable?
External shading is essential for reducing out energy use.