Fan to bring cool air from outside into a hot south-facing bedroom?

[ParentOfOne]

Has anyone installed a wall extractor/fan not to extract air away from a room, but to bring fresh air in from the outside? Something like this: www.vent-axia.com/range/traditional-t-series-wall-models

@PigletJohn do you have any experience with this?

We have two south-facing bedrooms on the first floor (in a house with ground, first, second floor). When it's hot, the north-facing rooms get some lovely breeze at night, but the south-facing rooms never do and always stay much hotter for much longer. E.g. now it is 20C outside, 25C in the north-facing room and 29C in the south-facing rooms.

I'd like to understand if a fan to bring fresh air in could help, and if there is a way to seal the vents in the winter, or if it then becomes too draughty when it's cold.

A fan in the room is next to useless when it's hot because it just moves hot air around - what I need is to bring cool air in from outside.

Thanks!

If your South facing I would consider aircon. Or an aircon unit.

External shutters require planning permission. I am looking into that but it's a very cumbersome process.

I have internal wooden blinds in one of the south-facing rooms - better than nothing, but the heat still enters the room (whereas anything external stops it from reaching the room).

One of the windows has solar control glass, and I have also added another solar reduction thingy transparent film, but they don't seem to do much.

I gave up on fans and purchased a mobile air con unit and im not going back ever again it’s absolute bliss in the worst heat. It’s extremely unhealthy to live in 30 degree heat inside flats that trap the heat, it’s the best way to care for yourself. It’s expensive to run but our summers aren’t that long.

I have aircon in the loft but

1. Anything that reduces the need for aircon, and therefore energy consumption, would be great
2. I'd rather not put aircon on the 1st floor, too

Our summers are not like the Greek ones but the point is not how often it's 30C outside, it's how often it's 30C inside!