Author Topic: Building thermal insulation.  (Read 9505 times)

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Online Zero999Topic starter

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Building thermal insulation.
« on: July 19, 2022, 03:20:54 pm »
It's been very hot here over the last two days with temperatures hitting 40oC, which hasn't been recorded in the UK before. We've all been warned about this and advised to do all the stuff that should be common sense, which I find a bit patronising.

One thing the mainstream media talk about is homes in the UK are designed to keep warm in winter, not cool in summer, as is the case in hotter climes. This may be true, but I've found my house's thermal insulation is working well.  It scraping 40oC where I live, yet I've managed to keep temperatures below 26oC in my house. I just opened the windows at night/early morning and closed them as soon as temperatures rose. I put aluminium foil over the window in the lounge, which doesn't have curtains or blinds. I have a modern house, built in 2016.

Maybe I'm being silly, but as I've just proven, thermal insulation works both ways, so even though it might be optimal, doubt it makes much difference whether thermal insulation is designed to keep heat in, or out. It's insulation after all. The main thing lacking is air conditioning.
 
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Online Gyro

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Re: Building thermal insulation.
« Reply #1 on: July 19, 2022, 04:14:11 pm »
Don't forget to strip it all out this evening, it's cooling down tonight!  ;)

Edit: The common sense stuff does work surprisingly well though, particularly closed windows, curtains and flushing the house in the early morning. Our '70s house doesn't have cavity wall insulation (dirty wall ties) but it still works.
« Last Edit: July 19, 2022, 04:18:12 pm by Gyro »
Best Regards, Chris
 

Offline mag_therm

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Re: Building thermal insulation.
« Reply #2 on: July 19, 2022, 04:36:09 pm »
How are the pubs holding up?
Pint of Bitter still  at 10 ~ 13 C ?
 
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Online ebastler

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Re: Building thermal insulation.
« Reply #3 on: July 19, 2022, 04:48:09 pm »
[...] I put aluminium foil over the window in the lounge, which doesn't have curtains or blinds. I have a modern house, built in 2016.

Maybe I'm being silly, but as I've just proven, thermal insulation works both ways, so even though it might be optimal, doubt it makes much difference whether thermal insulation is designed to keep heat in, or out. It's insulation after all.

With the aluminium foil you have addressed one of the "deficiencies" Northern homes have in heat waves: Too much sunlight coming in through large windows, and heat not getting out again due to the greenhouse effect. (Visible light passes through the windows, IR radiation does not.) Houses in Southern climates tend to have smaller windows, and/or windows better protected from direct sunlight.

The other difference might be "thermal mass". Heavy stone walls with a large heat capacity help with the summer heat, since their thermal storage capacity evens out the large day/night variation. They are less helpful in winter, where the temperature is more evenly cold throughout the day/night. Hence insulation optimized for cold climates will probably focus on low heat conductivity and less on large thermal mass.
 

Online nali

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Re: Building thermal insulation.
« Reply #4 on: July 19, 2022, 05:00:41 pm »
With the aluminium foil you have addressed one of the "deficiencies" Northern homes have in heat waves: Too much sunlight coming in through large windows, and heat not getting out again due to the greenhouse effect. (Visible light passes through the windows, IR radiation does not.) Houses in Southern climates tend to have smaller windows, and/or windows better protected from direct sunlight.

Our windows are fitted with Pilkington K glass which they claim enhances the greenhouse effect to trap heat. Unfortunately in this weather they seem to work a bit too well  :(
 

Online Siwastaja

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Re: Building thermal insulation.
« Reply #5 on: July 19, 2022, 06:20:09 pm »
You are obviously right about the insulation working both ways.

Passive means to combat heatwaves are,
* insulate houses properly,
* build small windows, or if you have large windows, use shades, blinds or best, just cover most of the window with aluminum foil, to minimize solar irradiance heat input
* keep ventilation at minimum during day (windows closed), and at maximum during night (all windows fully open). Or more exactly, replace as much air as possible whenever Tout < Tin.

Of course air conditioning is hard to completely avoid but letting many kW in through windows just to remove it with air conditioner is total waste of energy, and so is cooling a 25-degC room during night with a compressor if you have 20-degC air available by just opening the window.
« Last Edit: July 19, 2022, 06:26:34 pm by Siwastaja »
 

Online nctnico

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Re: Building thermal insulation.
« Reply #6 on: July 19, 2022, 06:58:57 pm »
It's been very hot here over the last two days with temperatures hitting 40oC, which hasn't been recorded in the UK before. We've all been warned about this and advised to do all the stuff that should be common sense, which I find a bit patronising.

One thing the mainstream media talk about is homes in the UK are designed to keep warm in winter, not cool in summer, as is the case in hotter climes. This may be true, but I've found my house's thermal insulation is working well.  It scraping 40oC where I live, yet I've managed to keep temperatures below 26oC in my house. I just opened the windows at night/early morning and closed them as soon as temperatures rose. I put aluminium foil over the window in the lounge, which doesn't have curtains or blinds. I have a modern house, built in 2016.
That is a modern home that has no problem with hot or cold climate. Homes build earlier than the 90's will have problems though. You can't just add insulation to those without adding (expensive) mechanical ventilation systems to keep the hummidity in check.
« Last Edit: July 19, 2022, 07:00:42 pm by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 
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Online TimFox

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Re: Building thermal insulation.
« Reply #7 on: July 19, 2022, 07:06:04 pm »
I have been a tourist when northern Europe was having abnormally-high summer temperatures.
(A headline in das Bild translated to "Is Berlin becoming Rome?".)
I was not surprised when inexpensive hotels did not have air conditioning, but I was surprised that there were no window screens to facilitate air breezes without wasps and mosquitos.
Berlin was also suffering from a wasp invasion that had killed at least one police officer;  the sidewalk restaurants had put out glasses of the syrups used for Berliner Weisse to keep the wasps from the customers.
(The poorest tarpaper shack in backwoods US has a screen door.)
 
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Online Zero999Topic starter

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Re: Building thermal insulation.
« Reply #8 on: July 19, 2022, 07:58:05 pm »
I have been a tourist when northern Europe was having abnormally-high summer temperatures.
(A headline in das Bild translated to "Is Berlin becoming Rome?".)
I was not surprised when inexpensive hotels did not have air conditioning, but I was surprised that there were no window screens to facilitate air breezes without wasps and mosquitos.
Berlin was also suffering from a wasp invasion that had killed at least one police officer;  the sidewalk restaurants had put out glasses of the syrups used for Berliner Weisse to keep the wasps from the customers.
(The poorest tarpaper shack in backwoods US has a screen door.)
Yes, it's not nice being here when during a heatwave. To those who say it's nothing, temperatures today have been 10oC hotter than the usual hottest summer day and over 18oC hotter than average. Overnight lows have been between 20oC and 25oC, 7oC to 13oC above normal.

Oddly enough, environmentalists have been concerned about a lack of wasps in recent summers. Although wasp plagues can be a nuisance, they do serve a purpose pollinating and eating other pests.

I got the hosepipe out and sprayed the outside walls last night. I was going to do the same today, but needed to water the garden and I would've felt a bit guilty wasting it. Incidentally I'd left the hose on the lawn from the night before and burned my hand because the water inside it had been heated to an extreme temperature. I suppose this shouldn't have been surprising.
 

Online TimFox

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Re: Building thermal insulation.
« Reply #9 on: July 19, 2022, 08:11:41 pm »
I have been a tourist when northern Europe was having abnormally-high summer temperatures.
(A headline in das Bild translated to "Is Berlin becoming Rome?".)
I was not surprised when inexpensive hotels did not have air conditioning, but I was surprised that there were no window screens to facilitate air breezes without wasps and mosquitos.
Berlin was also suffering from a wasp invasion that had killed at least one police officer;  the sidewalk restaurants had put out glasses of the syrups used for Berliner Weisse to keep the wasps from the customers.
(The poorest tarpaper shack in backwoods US has a screen door.)
Yes, it's not nice being here when during a heatwave. To those who say it's nothing, temperatures today have been 10oC hotter than the usual hottest summer day and over 18oC hotter than average. Overnight lows have been between 20oC and 25oC, 7oC to 13oC above normal.

Oddly enough, environmentalists have been concerned about a lack of wasps in recent summers. Although wasp plagues can be a nuisance, they do serve a purpose pollinating and eating other pests.

I got the hosepipe out and sprayed the outside walls last night. I was going to do the same today, but needed to water the garden and I would've felt a bit guilty wasting it. Incidentally I'd left the hose on the lawn from the night before and burned my hand because the water inside it had been heated to an extreme temperature. I suppose this shouldn't have been surprising.

Social insects are important, and are declining due to various environmental problems, but an inexpensive window screen can keep them from disturbing ones sleep.
 

Offline Gregg

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Re: Building thermal insulation.
« Reply #10 on: July 19, 2022, 08:43:26 pm »
I installed a product from https://atticfoil.com/ under the rafters with a fairly large plenum at the peak where I put an exhaust fan ducted to a grill in a gable.  The ceiling is insulated with fiberglass but before the foil install the top of the fiberglass would get to 165F at times.  Now with the fan running it may get to 85F and the bottom of the foil layer may get to 100F.
There are lots of Soffit vents to let in outside air. I ran 2x2 stringers horizontally where each course of the foil ended making a little more space for the outside air to mix and also made it easier to install the long foil sheets by myself.  There is also a gap all around the removable central panel that covers the fan to let air from the rest of the attic to be exhausted.  The fan is much larger than necessary to keep the temperature reasonable but it made it a lot nicer to work in the attic; now it has a speed control.  It is manually switched from below; I wanted to put a nice automatic control panel on the wall in a hallway but my wife thought that would be ugly.
 

Online Zero999Topic starter

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Re: Building thermal insulation.
« Reply #11 on: July 19, 2022, 08:53:01 pm »
I installed a product from https://atticfoil.com/ under the rafters with a fairly large plenum at the peak where I put an exhaust fan ducted to a grill in a gable.  The ceiling is insulated with fiberglass but before the foil install the top of the fiberglass would get to 165F at times.  Now with the fan running it may get to 85F and the bottom of the foil layer may get to 100F.
There are lots of Soffit vents to let in outside air. I ran 2x2 stringers horizontally where each course of the foil ended making a little more space for the outside air to mix and also made it easier to install the long foil sheets by myself.  There is also a gap all around the removable central panel that covers the fan to let air from the rest of the attic to be exhausted.  The fan is much larger than necessary to keep the temperature reasonable but it made it a lot nicer to work in the attic; now it has a speed control.  It is manually switched from below; I wanted to put a nice automatic control panel on the wall in a hallway but my wife thought that would be ugly.

My loft has loads of fibreglass insulation. There's no fan but I believe there's some ventilation around the sides. I'm not going to up up there to take a picture, until it's cooled down. I have no idea how hot it was there this afternoon, probably 60oC, 140oF.

I've just got home. It's 21:50 in the evening, the temperature is outside is 29.7oC, but it's 28oC upstairs and 25oC downstairs in my house. There's been light rain for the last half hour. Hopefully it will cool enough for me to open the windows soon.
« Last Edit: July 19, 2022, 08:56:05 pm by Zero999 »
 

Online Gyro

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Re: Building thermal insulation.
« Reply #12 on: July 19, 2022, 09:16:50 pm »
The temperature outside (22.20) is 20.7'C, down from 33'C at 5pm, that was a really fast drop. Bliss!

P.S. There isn't an opening in the house that isn't open and I'm considering making a few more! 150 200mm (I think) of fibre glass in the loft with soffit and apex vents btw.
« Last Edit: July 19, 2022, 09:24:35 pm by Gyro »
Best Regards, Chris
 

Offline tom66

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Re: Building thermal insulation.
« Reply #13 on: July 19, 2022, 10:08:46 pm »
I notice a lot of people had their windows open around here but when outside air is at like 40C it's probably counter-effective to cooling the building. 

A few homes around here have shutters that can cover their windows, I think this is a fantastic idea and will definitely be something to investigate before next summer.

Of course there does come a certain point when air conditioning is necessary, and while the UK does not currently get all that many 40C days even a 30C day can be uncomfortable if a few similar days have preceded it.  So I will certainly be installing it in our property.
 

Online Zero999Topic starter

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Re: Building thermal insulation.
« Reply #14 on: July 19, 2022, 10:54:00 pm »
The temperature outside (22.20) is 20.7'C, down from 33'C at 5pm, that was a really fast drop. Bliss!

P.S. There isn't an opening in the house that isn't open and I'm considering making a few more! 150 200mm (I think) of fibre glass in the loft with soffit and apex vents btw.
Lucky you. It's still above 25oC here and it's nearly midnight. I opened the upstairs windows first and now I've just opened the downstairs windows, because it's the same temperature outside as indoors.

I notice a lot of people had their windows open around here but when outside air is at like 40C it's probably counter-effective to cooling the building. 

A few homes around here have shutters that can cover their windows, I think this is a fantastic idea and will definitely be something to investigate before next summer.

Of course there does come a certain point when air conditioning is necessary, and while the UK does not currently get all that many 40C days even a 30C day can be uncomfortable if a few similar days have preceded it.  So I will certainly be installing it in our property.
I don't understand why some people open the windows in the middle of the day. It's generally better to keep them closed when the sun is out and open at night. Mine also have a security latch on them, but I don't bother as I live in a fairly safe area and there's nothing worth nicking in my house anyway.
 

Offline Benta

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Re: Building thermal insulation.
« Reply #15 on: July 19, 2022, 10:58:59 pm »
A few homes around here have shutters that can cover their windows, I think this is a fantastic idea and will definitely be something to investigate before next summer.

Of course there does come a certain point when air conditioning is necessary, and while the UK does not currently get all that many 40C days even a 30C day can be uncomfortable if a few similar days have preceded it.  So I will certainly be installing it in our property.

Perhaps you need to embrace the South German building style using exterior roller shutters.
https://www.neuffer.de/en/roller-shutters.php
Works wonders on the sunny side of the house.
Concerning air conditioning: I don't know the size of your garden, but a ground source heat pump will heat your house in the winter and cool it during the summer:
https://en.wikipedia.org/wiki/Heat_pump
And you'll save a heck of a lot of money on energy.
 
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Offline Halcyon

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Re: Building thermal insulation.
« Reply #16 on: July 19, 2022, 11:09:57 pm »
Thermal insulation is used extensively in house construction in Australia, both within the walls and the roof. It's designed not only to keep heat you generate inside the home from being lost, but also to keep the heat in summer from entering.

If you go into very old homes that don't have insulation (or very little of it), you can definitely feel the difference. They are like sweat boxes in summer and chilling in the winter.
 

Offline Someone

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Re: Building thermal insulation.
« Reply #17 on: July 19, 2022, 11:44:04 pm »
Yes, it's not nice being here when during a heatwave. To those who say it's nothing, temperatures today have been 10oC hotter than the usual hottest summer day and over 18oC hotter than average. Overnight lows have been between 20oC and 25oC, 7oC to 13oC above normal.
Its not "nothing" but its not a dire emergency, you can say its blah degrees more than normal but thats only what you are acclimatized to. The overnight minimum is a good measure as thats the best case possible with perfect insulation and no air-con, and often most disruptive (preventing sleep/rest). Australian city highest overnight minimums in the last 10 years (just the south east, no tropics):
Melbourne: 28
Adelaide: 34
Canberra: 27
Sydney: 25

All these places see daily maximums over 40 C routinely, yet air-conditioning is not universal: Adelaide 90%, others 70%.

Yes, heat is a bigger threat to life than cold, but that seems to have some strong acclimatization or behavioral content that London does poorly with:
https://www.eea.europa.eu/data-and-maps/indicators/heat-and-health-2/assessment
So the rest of the world will rightly point to the UK (London) and say learn to adapt with high and low temperature extremes, everyone else seems to survive better.
 

Offline David Hess

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Re: Building thermal insulation.
« Reply #18 on: July 20, 2022, 03:19:40 am »
The insulation works equally well both ways.  Opening a couple windows at night and using a fan to pull a draft through helps if you do not have air conditioning, but can be counterproductive if it is humid and you do have air conditioning because it will load the air in the house up with water which the air conditioning will have to remove later.

If it is hot and dry, then a swap cooler is nice.
 

Offline SeanB

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Re: Building thermal insulation.
« Reply #19 on: July 20, 2022, 08:50:09 am »
Remember during Gulf War I (the retrocon name given later) at work with us all watching TV to see the live war coverage. Helps to be in the same time zone as Bhagdad, and CNN popped over to the London correspondent about the current UK heatwave, with temperatures hitting the highest of 31C. Asked my colleague when was it 31C by us, and he replied it passed that at 07H15, and was, when he went through to tea, just a shade under 45C indoors. AC unit for our section having kind of moved large chunks of compressor off the roof a few months before when the compressor decided that throwing a rod was only the final thing, and threw heads off along with the rods.

Peak we measures was 75C 1m under the concrete roof, and we went through 100l of water a day, between the 12 of us in there. People looked at me funny when i remarked a few times how cool it was outside, only 41C, till they came in at lunch time. Most popular room was the ATE system, with it's separate AC system, made from 3 Defy 36000BTU console units, and those would be repaired post haste, as otherwise there would be no flyable aircraft.

Plenty of people came for winter holidays, and dropped dead from heatstroke, even before noon, while us that had been through a summer or two were out wearing jerseys, because 25C was cold to us.
 

Offline Miyuki

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Re: Building thermal insulation.
« Reply #20 on: July 20, 2022, 10:00:25 am »
I have an over a hundred years old house
And our ancestors have a smart solution to summer heat/sun heating
The roof overhang is designed so it shades windows during summer but allow all the sun to pass during winter months

I have added 24cm of styrofoam insulation on the northern wall and about 20cm is planned on other walls to keep both cold and heat outside and stable temperature inside.
As the house is built from stone and full bricks with walls 50-60cm thick, this provides massive thermal mass.
 

Offline PlainName

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Re: Building thermal insulation.
« Reply #21 on: July 20, 2022, 02:00:40 pm »
Our house is basically uninsulated, and we have a huge south-facing kitchen window (frame is metal and dating from the 40's or something).

On Monday we closed the (thin, red) blind on the window about 3/4 (too many plants on the windowsill to go the whole way) and kept the doors and windows shut. It was 37C outside and I didn't measure the kitchen but it was pleasantly cool. Even chilled, although that might be the contrast with outside. I belatedly noticed that someone was baking bread in the combioven!

Yesterday it was 40C in the shade and the same measures taken (less the bread baking). Bit warmer in the kitchen since the overnight temperature had been 23C, so it wasn't going to be cooler than that. Still pleasantly cool.

In contrast, my office has aircon which I set to 30C, translating to 27C actual, and that was noticeably warmer than the kitchen.

Summary: the trick of getting cool air in early then shutting out the heat and sunlight works very well. I think insulation would only show its worth if you had to use energy for cooling/heating (aircon, radiators), which would show up as reduced bills. But it's not necessary to combat extremes in the short term.
 

Offline Benta

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Online Gyro

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Re: Building thermal insulation.
« Reply #23 on: July 20, 2022, 08:56:52 pm »
Quote
The 21-metre rule is, according to the Stirling prize-winning architect Annalie Riches, a bizarre hangover from 1902, originally intended to protect the modesty of Edwardian women. The urban designers Raymond Unwin and Barry Parker walked apart in a field until they could no longer see each other’s nipples through their shirts. The two men measured the distance between them to be 70ft (21 metres), and this became the distance that is still used today, 120 years later, to dictate how far apart many British homes should be built.

 :-DD

Best Regards, Chris
 
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Online Zero999Topic starter

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Re: Building thermal insulation.
« Reply #24 on: July 20, 2022, 09:08:28 pm »
Yes, it's not nice being here when during a heatwave. To those who say it's nothing, temperatures today have been 10oC hotter than the usual hottest summer day and over 18oC hotter than average. Overnight lows have been between 20oC and 25oC, 7oC to 13oC above normal.
Its not "nothing" but its not a dire emergency, you can say its blah degrees more than normal but thats only what you are acclimatized to. The overnight minimum is a good measure as thats the best case possible with perfect insulation and no air-con, and often most disruptive (preventing sleep/rest). Australian city highest overnight minimums in the last 10 years (just the south east, no tropics):
Melbourne: 28
Adelaide: 34
Canberra: 27
Sydney: 25

All these places see daily maximums over 40 C routinely, yet air-conditioning is not universal: Adelaide 90%, others 70%.

Yes, heat is a bigger threat to life than cold, but that seems to have some strong acclimatization or behavioral content that London does poorly with:
https://www.eea.europa.eu/data-and-maps/indicators/heat-and-health-2/assessment
So the rest of the world will rightly point to the UK (London) and say learn to adapt with high and low temperature extremes, everyone else seems to survive better.
I question whether it's true that heat kills more, than cold in the UK. Look at the average temperatures for London and compare them to the graphs in the link. According to those graphs, our winters are consistently below the temperature which results in increased excess deaths, yet much less so in summer.

Now look at the extreme heat we had yesterday, compared to normal. A high of 40°C, 17°C above average. A low of 25.8 °C, 11.6°C above average and warmer than Sydney's record low. The hottest night of the year in London is normally around 18°C and there are only 2.5 days on average above 30°C. You're right the hot night was more of a problem, bearing in mind it was only <26°C for a short time before dawn and buildings wouldn't have reached anywhere thermal equilibrium, even with all the windows open.
https://www.metoffice.gov.uk/about-us/press-office/news/weather-and-climate/2022/record-temperatures-2022-a-review
https://en.wikipedia.org/wiki/London#Climate

This might interest you:
https://www.theguardian.com/commentisfree/2022/jul/20/britain-worst-built-homes-europe-extreme-weather-upgrade

It really isn't that bad. People need to invest on improving insulation. My parent's house is >70 years old and they fixed the insulation. The added the following: extra fibreglass was laid down in the loft, expanding foam cavity, double glazing and a conservatory which helps add another barrier. Their house is now nearly as good as mine, built about 65 years later.

Anyway, the weather is now back to normal. It's 18°C and pouring with rain.
« Last Edit: July 20, 2022, 09:10:16 pm by Zero999 »
 


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