The Cold Water Bottle Sleeping Test

Reading Time: 4 minutes

Since I enjoy experimenting with concepts and ideas I decided to get an empty 500ml bottle and fill it to almost but not quite full to allow for expanding ice not to destroy the cap. I then put it in a freezer for a day.

When night came, and as the time to sleep approached I wrapped the bottle of water in a barber’s towel and placed it under the duvert. The principle is simple. If people use hot water bottles in winter to keep warm, then I will reverse the idea, and use a cold water bottle to keep me cool. The test ran from around 22:00 to 04:00 with some success. There was still ice in the bottle, and it was still cold. It didn’t cause “burns” due to the towel acting both to absorb the bottle’s sweat, as well as to insulate me from direct cold.

Minergie Heat

In a Minergie building, especially under the roof, in a building where the stair chimney sits beneath apartments heat cannot escape, except through apartment doors. As every person opens their window for a cool breeze, on a hot day, such as the 27°c day we’re having now, so hot air enters. It warms up the air but it also heats up the mass of the building. The bricks, the tiles, the ceilings, the floors, and the air.

In a normal house you think “It’s getting hot, let’s close all the windows for the rest of the day, and move to the basement. In a duplex apartment, especially under the roof you get heat from open windows, if you open them, but also from the walls, and the floor.

For the sake of intellectual curiousity I have spent years trying different methods to keep cool and all of them have failed except one. Waking up at the same time as song birds, at 4am to open the flat door, and the windoor to the balcony.

The idea is that the basement is cool and open and the stairwell is hot, and sealed. If you open the stairwell for five minutes or less, then air barely moves, but if you open it at dawn, when there is a massive thermal difference between the stairwell and the flat, then you get a tremendous flow of air. That flow of air, if it’s allowed to flow.

The Diving Analogy

Imagine that the stairwell is the airway and the garage is the lungs, and the outside is the air you’re trying to breath in. If you hyperventilate, or take breaths that are too shallow, you only move that volume of air up and down. The aim is to encourage a full breathing cycle.

By opening the windows at 4:30 or so, and opening the flat door, you’re getting the hot air in the hallway to be dragged outside, into the fresh air. Fresh air that is breathed in through the lungs enters the stairwell, cools it, and cools the walls. If you’re patient the hot, humid air is purged, to be replaced by fresh, clean air.

There is a point when the flow of air dies off, and the air becomes static. That’s when you close the door. Now, the building is sending heat from the walls, tiles, and other surfaces, and saturating the air. In effect the building can radiate the stored energy outwards into the cooler air, rather than the apartments.

The building that was optimised for trapping heat in winter, to earn a high rating becomes like a sealed car in a summer parking. The air is trapped, and every day that is hot, more heat energy is stored within the building. During a heatwave you see the temperature rise from 24-27 degrees in just a few days, and that’s just the minimum temperature.

The room I sleep in warms to 31°c in the afternoon, but when the sun disappears it sticks to 29°c, and with two hours of ventilation, between cool morning air, the room sticks to a two degree difference, that either sticks to the temperature you achieved, if you’re lucky, or shoots up, as is usually the case.

The solution is tremendously simple. In the top floor bedrooms you add an automatic vent so that when the temperature reaches 26°c the building begins to vent excess heat, non stop, until summer is over, and once the temperature is below 24°c it automatically shuts.

That simple vent would keep the stairwell healthy and cool, rather than warm and stale.

Back to the Cold Water Bottle

Since we can’t cool the structure that is designed to trap heat in winter and summer there are two solutions. Open windows and mosquito nets all night long, or cold water bottles. The principle of the water bottle is simple. You get one, two, or more bottles and you place them under a duvet. The water bottles have huge specific heat capacity so they can cool the space under the duvet, and the duvet insulates you from the warm bedroom.

The advantage of the water bottle solution is that once a bottle is frozen it cools for hours, whereas a fan, and air conditioning, only cool while they’re running. If you have three or four bottles in a freezer, then for a fraction of the energy used by air conditioning you have a cool duvet. You don’t need to cool an entire room, to stay fresh at night.

Sometimes lateral thinking provides a simple, temporary solution. Essentially it’s reversing the hot water bottle principle.

#duvet #heat #ice #summer #water

@patrizia

Nah, it's easy. Even I can put on a king-sized #duvet cover in two minutes flat. Weighted duvets aren't a problem, either. Look up "California roll duvet" on your favourite oligarch's video-sharing site — for instance:

https://www.youtube.com/watch?v=c1IzS2oBBN0

The crux of the technique is the action of making a pocket in the duvet cover after you've rolled everything up, and I can't find a video that does that slowly enough to make it clear. The key is to put your hand in the opening of the duvet and then pull the corner of the duvet from the inside until it reaches the opening. This forms a pocket on the outside of the duvet. You then take the end of the jam roly poly and stuff it into the pocket you've just made. You can, if you wish, do the same at the other side and then sort of turn everything inside out until it all meets in the middle, but I just make one pocket on the left and work rightwards from there.

It'll feel a bit weird the first time you do it: you'll reach a point where you're sure you've done it wrong, and then it'll suddenly work, and you'll think, "But that's impossible!" Once you've mastered it, you won't go back.

@schratze @fesshole

How to Put on a Duvet Cover: The California Roll Way

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a playlist just to feel something

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I learned recently in Europe (and I guess, Gen-Z), they use just a #duvet/duvet cover.. no top sheet.

I dunno how I'd feel about that. All my beds do have feather duvets too, but over #wool blankets. In the case of my bed, a wool topper also (and a heated mattress pad).

I use wool even in the summer, just swap #flannel for #tencel sheets. It's crazy how well wool thermoregulates. I think Europeans are missing out on this one.

Fediversians ~~ what is your best #bedding tip?!

Erstmals im #Leben bzw. eine radikale, persönliche #Veränderung: Schlafen 😴 mit #Duvet aus #Wolle 🧶 statt #Daunen 🪶 — herrlich! 👍 Mit Bettbezug aus #Leinen.

Es hat sich noch viel besser angefühlt als erwartet. Kein #Schwitzen mehr, angenehm anschmiegsam, leicht, tiefer #Schlaf.

Es war definitiv die richtige #Entscheidung für mich. 🛌🐑🧶 Und kostet etwa die Hälfte.💰

#leben #veranderung #duvet #wolle #daunen #leinen #schwitzen #schlaf #entscheidung #Bett #bettwaren #bettwasche #komfort #nacht

Bôa - Duvet (Official Video)

Duvet, taken from Bôa's album 'Twilight'. Available to listen or download here: https://boa.ffm.to/twilightCredits:Produced and directed by Alex Parkinson.Ly...

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Creative Parenting Activity #17: Try quilting. Start with a small project such as a placemat, blanket for a stuffed animal or quilted pillow case. As the skill develops consider motivating your child by making a present for a school mate, a baby in your extended family or for children living at your local battered women's shelter.... https://rons-home.net/en/living-life-lab/tool-box/creative-parenting-activity/activity-of-the-week/2026/03/03 #sew #quilt #duvet #bedspread [Next Tip Mar 10 2026]
Activity #17 :: Activity Of The Week :: Creative Parenting Activity :: Life Skills Tool Box :: Living Life Lab :: Ron's Home

We are fully paid up members of The Hellfire Club!
#hellfireclub #strangerthings #duvet
We are fully paid up members of The Hellfire Club!
#hellfireclub #strangerthings #duvet
We are fully paid up members of The Hellfire Club! #hellfireclub #strangerthings #duvet