You need the blinds on the outside of the window, otherwise this helps minimally, especially if the whole southwest facing wall is glass, which turns the apartment into a greenhouse.
During the heatwave, night was the only time I could cool the room with portable AC, provided all windows were closed to not let heat in.
We have a massive south facing side filled with windows (and two double glass doors), covers about 80% of the living area, all blinds mounted inside. We still had 9°C lower temps inside compared to outside during the worst hours of the heat wave. Yes 28°C is still hot, but much better than the 37°C we had outside.
You need the blinds on the outside of the window, otherwise this helps minimally, especially if the whole southwest facing wall is glass, which turns the apartment into a greenhouse.
During the heatwave, night was the only time I could cool the room with portable AC, provided all windows were closed to not let heat in.
We have a massive south facing side filled with windows (and two double glass doors), covers about 80% of the living area, all blinds mounted inside. We still had 9°C lower temps inside compared to outside during the worst hours of the heat wave. Yes 28°C is still hot, but much better than the 37°C we had outside.