I do think this all a bit alarmist.

Insulation is good at maintaining a temperature differential. Whether it’s colder outside and warm inside or warm outside and cold inside.

Four things are required to be ready for high temperature:

• External shade: Whilst covering rooms from the sun inside is better than nothing, the shading needs to happen on the outside of the building.
• Cooling capacity: A reversible heat pump works for heating and cooling a house. Typically it’s needed on upper floors, as this is where the heat gathers.
• Common sense (there is no hope): If it is warmer outside than inside, opening the windows lets in the heat. I cannot fathom how many people cannot understand this simple fact.
• Local convection: Fans increase temperatures inside the house overall, but if set to directly blow on people or made to distribute cool air into the warmer zones, they can add on the local cooling.

We live in a south facing property with two French doors. It was absolutely horrid before we:

• Installed an enormous awning that shades almost of the downstairs zone
• installed two temporary air conditioners (not fans, actually heat pumps) in the summer months.
• opened windows in the morning to let in the cooler morning air, then kept everything shut tightly once the day heated up.
• Drew curtains on the upstairs south facing rooms.

Now our house is cooler and quite pleasant even when we are in the high 30s.

I am astounded at how many people violate these basic principles or install temporary air conditioners and stick the hose outside an open window. They are literally doing basically nothing. We ordered custom plexiglass insets for our top opened windows with a precise cutout for the aircon house. Cost us like £25 quid per window and now the upstairs is often colder than downstairs.