The British house is designed for staying warm. Cavity walls, loft insulation, double glazing, draught excluders shaped like sausage dogs. Every improvement made to our housing stock in the last hundred years has had one goal, which is to trap heat indoors and refuse to let it leave. For most of our history this was entirely sensible. Then the summers changed their mind.
Now, for a few weeks a year, we all live inside extremely well-made thermos flasks.
Built for January, tested in July
It is not that British houses are badly built. They are very well built, for a climate we are slowly ceasing to have. A house designed to hold on to every degree in winter does exactly the same thing in a heatwave, except now the heat it is lovingly preserving is the stuff you want rid of. Brick soaks up warmth all day and releases it all night, which is why the worst hour in a British heatwave is often 11 o'clock in the evening, lying on top of the duvet, wondering why the bedroom is hotter than the garden.
Air conditioning, the answer in most hot countries, barely exists here. Only a small fraction of UK homes have it, and given that the hot spell might last a fortnight, most of us are not about to install it. So we fall back on the national heatwave toolkit: a fan from Argos, closed curtains at midday, and the phrase "it's not the heat, it's the humidity" repeated to anyone within range.
The advice everyone gives, and its one flaw
Ask anyone how to cool a house without air conditioning and you will get the same answer, because it is the right one. Keep the sun out during the day, then open everything up in the evening and get a through-draught going, so the cooler night air can flush the warm air out. Windows at the front, door at the back, let the house breathe.
The flaw is the door. An open window three feet off the ground with a fly screen's worth of net curtain is one thing. A wide open doorway at dusk is an invitation, and everything in the garden accepts. Moths with no plan, bluebottles with too much of one, mosquitoes from next door's water butt, the occasional bewildered crane fly. Which is how the great British compromise happens: the door gets closed at exactly the moment the outside air finally turns useful, and the house stays warm out of self-defence.
Letting the house breathe without the guest list
This is the doorway problem, and it is precisely the problem a bead curtain was invented for. The Mediterranean has been running this experiment for generations, in a climate we are apparently in the process of ordering. Every taverna doorway stands open all evening, air drifting through, flies largely giving up at the threshold, because a wall of gently moving strands is more negotiation than most insects can be bothered with.
Hung in a back doorway here, it does the same job. The door can stand open from teatime until bed, the through-draught actually gets to happen, and the moths stay outside headbutting the porch light instead of the kitchen one. It also softens the view in, which matters if your back door opens onto a shared alley or a neighbour's fence line and "wide open all evening" otherwise feels a bit exposed.
What it won't do
A bead curtain does not cool anything. It has no moving parts beyond the ones the breeze provides, and it will not lower the temperature of a single brick. What it does is remove the reason the door keeps getting shut, and the open door is what does the cooling. It is a small fix for a problem our houses were never designed to have.