The amount of heat in the air is small compared to that in other materials; buildings with stone or concrete walls have a sufficient heat capacity that you can ventilate without temperature changing too much. This works less well for buildings with wooden walls though.
Ventilating properly requires discipline though. No tilted/semi-opened windows for prolonged time for example. In winter, heating should be turned off and the windows should be as wide open as possible to minimize the time to exchange air. That's to reduce the loss of heat. 5-10 minutes of ventilating is good enough, usually. We usually don't have air condition here, so I don't know what's the recommended process in the summer.
It's common to ventilate like this in Germany in the winter for example. I know (now returned) former German expats that completely missed this development. They still tilt windows and let the heating run all day long.
Ventilating properly requires discipline though. No tilted/semi-opened windows for prolonged time for example. In winter, heating should be turned off and the windows should be as wide open as possible to minimize the time to exchange air. That's to reduce the loss of heat. 5-10 minutes of ventilating is good enough, usually. We usually don't have air condition here, so I don't know what's the recommended process in the summer.
It's common to ventilate like this in Germany in the winter for example. I know (now returned) former German expats that completely missed this development. They still tilt windows and let the heating run all day long.