Earth Notes: KEHS talk: Keep Cool and Carry On (2025)

[00:00]

[Marilyn] Why are we worrying about heat these days?

[00:03]

It's interesting because Damon and I have been doing these talks for quite a while.

[00:07]

In that time, there has been growing concern about overheating,

[00:11]

maybe because of climate change and the realisation that

[00:16]

thousands of people die from overheating in a heatwave,

[00:21]

not to even mention the lethargy and discomfort that goes with overheating.

[00:28]

And we're not very good in this country for historic weather reasons,

[00:34]

knowing how to keep cool.

[00:38]

We still tend to throw windows open even at inappropriate times of the day.

[00:43]

We haven't needed to worry about this in the future,

[00:46]

but I think we do increasingly need to worry and prepare for the next heatwave.

[00:51]

So, keeping cool. What can we learn from hot climates?

[00:54]

It always surprises me - people go to Spain and the south of France, etc. for holidays,

[00:59]

but they don't seem to notice how people in the south of France and Spain regulate their lives.

[01:05]

It's very different from ours. And one of them, of course, is timing your activities.

[01:10]

The old Noël Coward song, "Mad dogs and Englishmen // Go out in the noonday sun."

[01:15]

It's quite right. Take a siesta at midday if your life permits,

[01:19]

but if you can't, early morning is easily the coolest and best time to do heavy work.

[01:26]

People who get up late don't know what they're missing in the summer.

[01:29]

It's lovely first thing at 6 or 7 o'clock, but it stays hot for a long time.

[01:34]

So, that's first lesson.

[01:37]

Keep an eye on relative temperatures.

[01:40]

Don't open your windows at noon when it's actually hotter outside than inside.

[01:46]

And again, you'll notice from our friends on the Continent that they don't do that.

[01:51]

When it's hotter outside than in, and it's not that difficult to tell,

[01:55]

you've only got to step out the back door,

[01:58]

close your windows, especially south-facing ones,

[02:02]

draw curtains to keep the heat and the sun out,

[02:05]

and then reopen your windows quite late at night.

[02:08]

It's not symmetrical. It's nice early in the morning.

[02:12]

It stays warm quite a long time into the evenings,

[02:16]

but at sort of bedtime you can open your windows.

[02:20]

And learn to love shade.

[02:24]

I noticed my neighbours in their gardens,

[02:27]

they're forever cutting back trees, and they don't like shade.

[02:30]

I think that we've got to learn to love shade.

[02:34]

I would recommend, particularly, deciduous climbing plants

[02:40]

on a gazebo or a pergola,

[02:44]

because they'll shade you in the summer,

[02:47]

and then they'll drop their leaves in the winter,

[02:49]

and you'll get the light that you want in your house.

[02:52]

Because I think we've traditionally had grey skies and lots of drizzle and cool weather,

[02:57]

we tend to not like shade and to have big windows

[03:00]

and cut down trees because they're shading your house.

[03:04]

In fact, I think as life goes on, you'll probably welcome those.

[03:08]

Get to know your home.

[03:10]

Everyone knows in theory that heat rises,

[03:13]

but we don't often act on it.

[03:16]

Upstairs and roof spaces may well be the hottest parts of your house.

[03:21]

You might find it better to sleep downstairs if you can arrange it.

[03:27]

And certainly at the height of the noonday sun,

[03:32]

retreating to the coolest room in the house,

[03:35]

which might be the darkest room in the house, or it might be the room that faces north,

[03:39]

will make your life much more comfortable.

[03:43]

You need to pay special attention to south-facing rooms and windows.

[03:48]

I think, again, on the Continent, you probably wouldn't have huge expanses of glass facing south.

[03:54]

You do here, because we're still learning how to cope with heat, I think.

[04:00]

And one thing, and we've had quite a lot of myth-busting this morning,

[04:05]

it is not true that insulating your house will make it hotter in the summer.

[04:11]

And you've only got to think, you know,

[04:13]

if you were taking a nice cold bottle of wine to your friend's house for lunch,

[04:17]

what would you do to keep it cool?

[04:19]

Any suggestions?

[04:21]

Yes?

[04:23]

You drink it perhaps!

[04:25]

But yes, you insulate it, basically.

[04:27]

You grab it in something to keep it cool.

[04:30]

And as I say, all the insulation that everyone's been talking about

[04:32]

this morning to keep your house warm in the winter,

[04:35]

will also help to keep it cool in the summer.

[04:39]

I'm going to talk about a few feasible home improvements.

[04:43]

You could consider low-emissivity window film,

[04:46]

which has been mentioned in the context of keeping homes warm.

[04:50]

It will also help to keep it cool.

[04:52]

External shutters and blinds, such as they have on the Continent,

[04:56]

are excellent for this, but not very easy to accommodate.

[05:01]

If anyone looks at the windows in this room and they open outwards,

[05:04]

that would not work if you had an external shutter.

[05:07]

And I think it would be quite difficult to organise in this country.

[05:12]

We've got a thermal image.

[05:15]

And that's what a patch of low-emissivity film just stuck on your window

[05:22]

will do, it'll make it much cooler.

[05:26]

So it's an interesting thing to do if you can.

[05:30]

Oh, yes, use a fan with a timer.

[05:33]

I'm not going to recommend things like air conditioning and fans,

[05:36]

because it's going to increase your energy usage.

[05:39]

But a fan with a timer that you can have going for an hour or so

[05:44]

when you're trying to go to sleep at night works pretty well we've found.

[05:51]

Air conditioning, well, I'm not going to recommend that.

[05:55]

There are, and Damon might be able to talk about these better than I can,

[06:00]

you can get warm air heating systems

[06:06]

that will also blow cold air around your house.

[06:08]

But again, if you haven't got them, it's probably a step too far

[06:12]

to actually even start that kind of improvement.

[06:18]

Visit cool spaces on a really hot day.

[06:21]

I mean, this is an astonishingly cool room.

[06:23]

It's quite warm outside.

[06:25]

It must be pretty well insulated, I think,

[06:27]

because it's actually, I've been feeling cold.

[06:29]

[Damon] ... With the sweat of teenagers.

[06:31]

[Marilyn] I don't know.

[06:33]

But anyway, I reckon this is quite a well-insulated room.

[06:37]

Drink lots, save water, take showers rather than baths,

[06:42]

use grey water in the garden.

[06:44]

There are all those sorts of things that I think pretty soon

[06:47]

we're going to have to be thinking about this summer, because we've had very little rain recently.