New windows here in Norway are often triple or quadruple glazed, and they have a pretty good R-value; so they are not that much worse than average walls at least.
The best window I can find from the major Danish manufacturer Velfac has a total U-value of 0.82 W/°K/m² [1]. It's a triple-glazed window with argon and coatings.
A typical insulated thin (100mm) wood-frame wall, i.e. the sort you'd use if you were building a summer house in Sweden has a U-value of 0.4 W/°K/m² [2], i.e. twice as good as the window above.
A typical rock- or glasswool insulated wood-frame wall for a modern year-round house has a U-value of 0.2 W or better, i.e. four times as good as the window above.
Wall that are so bad that they're roughly equivalent to the triple-glazed window above are something you'll mainly find in buildings from 50+ years ago, at least in Sweden. I expect Norway to be similar. [3]
'bjarneh' mentioned both triple- and quadruple-glazed windows. I've only seen quadruple used in noise-reduction applications, e.g. hotel next to a busy road. If you have a data sheet for one, it'd be interesting to see what the U-value is.
One of the posters above referred to 'R-value'. It's the reciprocal of the U-value. Wikipedia has good explanations of both, as well as typical values for windows and walls. [4,5]
References are mostly in Swedish, because the poster 'bjarneh' was talking about windows in Norway, so I wanted references for companies that actually sell things in Scandinavia.
[1] https://products-api.velfac.com/files/11644/VELFAC%20STANDAR...
[2] https://www.isover.se/hur-tjock-isolering-ska-man-ha-att-fa-....
[3] https://www.traguiden.se/konstruktion/konstruktiv-utformning...
The ones we got for our house was ordered with noise reduction, but I think that basically just meant that they did not have that little valve at the top of the windows (ventil in Norwegain perhaps also in Sweedish?).
My situation is somewhat special since I have a very old house (built around 1850) made from a timber frame construction (timmerkoja in Sweedish I guess?). So the walls were extremely poorly insulated, basically just some wool (or something similar, not 100% sure what it was) between the beams as they were put on top of each other during the build. Regular boards where added on both sides of the timber frame, but no additional insulation until we renovated the house.
The 50 year old punctured double glaze windows - that came with the house were not doing too much in terms of insulation either.
Any insulated wall will probably be better than windows, but at least here in Norway, there are a bunch of old poorly insulated houses, with double glazed windows as most everyone got these things installed when they came out:
Husmorvinduet (housewife windows) was popular since they were so simple to clean; and electricity was cheap until quite recently I guess. But any wall with actual insulation will probably beat windows for insulation; although newer windows are not as terrible as the once were.
> so I wanted references for companies that actually sell things in Scandinavia
I guess they are manufactured elsewhere; but I think the ones we ordered was delivered from Røros-vindu, but I could not find any info about actual R/U-value for the windows on their website. Just some info about what types of gas they contain and so on.
Supposedly, windows with an outer self cleaning layer get less condensation, but they're quite expensive.
I don't notice a difference now that I have two double glazed windows on top of each other (kobla vindu - I don't know the English word for it), I'll include a picture here:
https://spesialvinduer.no/wp-content/uploads/2019/08/Skaara_...
In the UK we'd call this secondary glazing if I'm understanding the image correctly.
Although I have seen in Alaska where they do double glazing windows on the outside as storm windows, then about six inches to a foot inside of that, they have another layer of double glazing. Yes, the walls are super thick.
How long is such a window rated for? Surely the gas will eventually leak out?
Still, leakages happen, you recognize that usually by water/steam between the two glass panes. If the windows aren't to old you can just switch out the glass leaving the plastic frames. If they're older (30 yrs) it's more economical to switch out glass and frames.
https://www.haustechnikdialog.de/Forum/t/65875/Haltbarkeit-A...
It’s worth it to manufacture windows like this, but unless you’re in the arctic circle I wouldn’t worry about the difference.
Here's an argument that heat capacity shouldn't affect thermal conductivity in a solid: imagine a block of material with a smooth temperature gradient through it and the temperature at any point remaining constant, so there is heat flowing through it. Now imagine you have some tiny beads of some other material with a super-high heat capacity. Distribute those beads throughout the block of material, preheating each bead to the correct local temperature before inserting it. Then intuitively it seems that neither any local temperature nor the rate of flow of heat through the block should change much. Yet the heat capacity of the new composite material is significantly higher than that of the original material. Does that argument make sense? I did physics at school but not since then!
But in a gas, heat transfer is mostly driven by convection. Gas near the hot surface heats up, rises, moves to the cold surface, falls, and repeats. So what matters is the specific heat capacity * the flow rate between hot and cold surfaces.
Conceptually, it's like a thermos bottle, and you'd think that you would want a vacuum, but apparently that's hard to keep intact on windows, so a noble gas between the layers works better.
(While every noble gas has roughly the same heat capacity by mole/volume. Perhaps some CFCs would have been even better for insulation, but bad for the ozone layer, of course, and rightly banned?)
For the nearly eight years that my wife and I lived in Brussels, Belgium, we lived in an old house (rented) that was built around 1910, and so we didn't have even double glazing, although we did have French Doors, and we had custom-made screens that had to be manually placed into the windows and then pinned in place with a nail instead of always attached to the outside. So, I don't have much knowledge of what current European building standards are in this space.
I do prefer the German-style double-opening windows that I saw in the house my sister-in-law was renting near Spangdalem AFB, along with the Rolladen that they had installed. But again, that was a rental in an older home.
I have been watching Laura Kampf and her "Haus Lise Lotte" project on YouTube, but again that's a 120 year old house, and they haven't gotten to replacing the windows yet.
Any suggestions for an English language channel where I could learn more about current European building standards, maybe something like Matt Risinger's "Build Show" for US building standards that I've been watching on YouTube?
My point was only that a vacuum gap is still not a perfect insulator, so it's an economic trade-off.
My experience is it's either too cold to open the windows, or you will want the windows open - in my part of Denmark.
*Some people enjoy having more hot days during the summer, of course.
Edit: one such product http://www.reflex.si/en/q-air
Not everyone is bothered by this though, but I think a house should have at least 21C in winter.
Discussion should focus on energy budgets or total energy use, but that may be hard to conceptualize for the average Sven.
Thankfully two or three years ago, we signed up for amber.com.au which will give you real time pricing and alerts so we can be thoughtful about usage in peak demand.
I've been tracking usage via their API for ~two years
https://flatgithub.com/dalanmiller/electricity?filename=3121...
Source: spent a few summers fetching water from a well and crapping into an outdoor toilet.
By building profile I mean, higher requirements if you want massive windows; to account for their lower R rating than a wall.
Or higher requirements for a rectangular footprint vs a square footprint because the rectangle has a more surface area for the same volume.
(Does anywhere take this approach???)
It's the walls must be X, windows must be Y:
https://dibk.no/regelverk/byggteknisk-forskrift-tek17/14/14-...
In a nutshell, stone, concrete, metal, and glass are very good at transmitting heat, so the inside of your house will quickly be as hot (or as cold) as the outside. Plastic, wood, and especially air are very bad at transmitting heat (or good resisting to heat transmission) and this is what you want for your house. Back to windows, multiple sheets of glass are only desirable because they have an air chamber inside. Three layers of glass mean two air chambers, each at its own temperature.
I’m confused by what you write about stone and concrete being good at transmitting heat. I thought the point was that (a) they act as an accumulator regulating the temperature because they take a lot of energy to heat up and (b) they conduct heat poorly (or worse than a window would be mm of thickness but they are much thicker) which is insulating.
Looking up random values from the web, it seems a the low numbers for a thin concrete wall (single wythe means no cavity insulation) are about 2.5x those of a coated double glazed window. A wall which is thicker or has insulation will perform much better. And this doesn’t count any insulation from plaster or cladding or whatever.
Concrete: 0.8 W/m^2K for 10cm solid dense concrete. https://ncma.org/resource/rvalues-ufactors-of-single-wythe-c...
Window: 2.1 W/m^2K for a coated especially insulating window. https://www.justrite.com.au/products-and-services/double-gla...
I wrote about conductivity here because that’s what your comment seemed to be about. Maybe I misunderstood your comment because it seemed to me that you were implying that windows transmit less heat than eg concrete walls (reading carefully, you don’t write that) and I thought it was a given that they transmit more heat. But my question isn’t about adding windows making a building require more heating but about adding windows making a building’s temperature harder to maintain because there are not a load of big (eg) concrete blocks in the wall releasing their heat into the air after you open the door and let a load of cold air in.
This depends on climate.
When the outside temperature changes, the building will eventually get itself to the outside temperature (thermodynamics laws). How fast that change would happen exactly — depends on thermal resistance and thermal mass.
Thermal resistance acts as an amplifier (or rather diminisher) of that changing force: the higher the resistance, the lower is the force, and so more time for the change to take effect.
Thermal mass acts as a momentum against that changing force: the higher the mass, the more time for the change to take effect.
In some climates (e.g. south Europe) the outside temperature is only a problem on winter nights and on summer days. You are only fighting the outside weather for hours on end. And you can effectively make that fight with large thermal mass alone.
In other climates (e.g. north Europe) the low temperatures at winter can come for months, so you want mass, resistance, and inside heating.
However, getting that ventilation using trickle vents in windows is just a stupid way to do it. You're letting all the heat vent out, and letting the noise in. A better way is with a mechanical ventilation heat recovery (MVHR) system. That sucks air out of some rooms (the bathroom and kitchen are recommended), and passes it through a heat exchanger before pushing it outside, while simultaneously pulling in fresh air from outside, heating it up in the heat exchanger (for free) and blowing it into other rooms (such as bedrooms and the lounge). This is the proper way to do it.
A MVHR system only really makes sense if your house is otherwise fairly non-leaky. However, if you do install it, then it can take over the bathroom and kitchen extraction, and it allows you to plug all those leaks and insulate well, without causing stale air problems.
MVHR makes total sense and sounds superior. I’m sure the builders have successfully lobbied against such a sensible suggestion for decades and that’s why we have (I imagine) such stupid and basic solutions in our building regulations.
I feel like UK houses lack infrastructure that the likes of the US and Europe have. Even kitchen ventilation is such an afterthought
1) huge thickness thermal insulation on the exterior
2) double/triple gaze (airtight minus the small built-in ventilations) windows
3) NO added mechanical ventilation
The bets are on on how long it will take for people to realize that if they do not vent manually the house humidity/mould will form.
This has already happened for houses built some 10-15 years ago (the first houses built as Class A or Class B) that - even if newly built - did not usually provide mechanical ventilation.
There are on the market since a few years small "in-pipe" mechanical ventilators, including a heat exchanger, basically you make a 100 or 120 mm hole in the wall and put in it a pipe that contains the vent and heat exchanger, they are very suitable to install "as an afterthought".
Trouble is that they work on "alternate cycle", i.e. they suck air from the inside for - say - 30 seconds (warming the heat exchanger), then they push air from the outside for another 30 seconds, and they may be (or become) noisy, new models have built-on timers to be able (as an example) to switch off at night if in bedrooms or switch off in the evening in the living room, etc.
What is the R-value of a Norwegian wall?
That varies greatly I think. There are a lot of old houses here; built to a very different standard than a modern house. Double glazed windows has been the norm for a long time though, through the invention of the easy to clean husmorvinduet or h-vinduet:
Husmor translates to housewife, vindu to window (housewife window). Easy to clean, since they can flip around, i.e. you can wash the outside from the inside. So for most older homes, I guess it's a mix.
For new buildings; what you say holds true I think.
Speaking for myself here, my house was built around 1850-1861 (no one really knows when it was made exactly). Timber construction covered with boards on both sides; but with minimal insulation (until we started renovating the house).
There are stricter rules for building new homes now, then what they had in the 1850's of course :-). A new house built now should follow the TEK17 standard made into law in 2017 (prior versions are the TEK10 standard from 2010, TEK07 from 2007, TEK97 from 1997 etc.). They regulate everything, from how much area you should have outside to how big a shed you can set up I think. Eco friendliness is an important category though; and these are the minimum requirements that came up with a google search (in Norwegian) for your question:
https://dibk.no/regelverk/byggteknisk-forskrift-tek17/14/14-...
Unfortunately in Norwegian as well, but they do state how much a wall/roof etc is allowed to leak; i.e. U value. As you can see (with Goole translate at least), walls should have better insulation than windows at minimum at least.