South glazing low emissivity or NOT?

[minguinhirigue]

Small stone to the building:

Having read the book of Jean Pierre Oliva and many other tests, year-round, in most regions of France, the thermal balance (solar gains - thermal losses) of good double glazing is often better than that of triple glazing, so i advise you to stay on your first choice lolus: double glazing.

Afterwards, there is a distinction between glazing with low emissivity or not (reinforced insulation with argon being another question): glazing with low emissivity essentially limits infrared radiation, it can be useful against nighttime heat losses by radiation, or against summer overheating ...

But that means, as several members have said, that it limits solar gain in winter!

So, look precisely at the values ​​of the solar factor (G) of the glazings which are proposed to you (depends on the manufacturers), if the difference is small, opt for low emissivity, if not, no!

Know also that you can choose simple shutters and decide the question: no low emissivity if you have shutters. At night or in hot weather, the shutters are closed.

Good luck in your choice.

[lolus]

thank you for your answers.

I think like did67 and minguinhirigue that is what it seemed to me.

I'm looking for a max. calorie in winter and actually my slab will be thick and terracotta on the ground so no pblm of inertia a priori.
At home it can be very cold in winter (750m) and very very hot in summer so in summer to avoid the heat I plan a cap as you said did67 and possibly a pergola with cannis or other to protect me from the heat. and if I choose standard glazing the savings can pay me the wood to make shutters ....

After I just reread the book by jp oliva

Forcing the solar factor of FE and less good than standard double glazing just with argon gas

He says if I get it right that even if it is lower and the lower solar gain is compensated by better insulation.
On the other hand, a low-emissive glazing will have its interior glass warmer so no "cold wall" feeling when you pass in front of it and no cold convection in front of the window as is the case with a classic double glazing .... .



On the other hand the IR it seems to me that it will just heat the bodies on which they type which explains that the air will not be warmer but on the other hand a panel or a person behind will have more sensation of heat and will radiate from hot . As we can be hot in full sun even if it is 15 degrees outside and it is good to enjoy it with an anti IR screen we will be cold .... I will tend to reason like that ...

So it is better to preserve your calories inside and not accept that from the inside or lose a lot of calories from the inside but gain it by IR radiation and the big question .....
Maybe the low emissive no just brings a better perceived feeling when the sun is beating ....

The choice and difficult to do in any case if you have other additional info I am still interested because I hesitate always ... even if I can save $$$$ by taking a low emissive

So the choice and difficult

[fthanron]

There is this commercial site with a technical study carried out by the firm TRIBU which deserves to bring some caveats to the statement "in the south no triple glazing": http://webcast.yourglass.com/tri/

@+

[lolus]

Triple glazing I do not ask the question it is too expensive bcp and it involves very thick carpentry where an additional cost of at least double .... I have twenty opening so you see the budget ... ...


To return to the basic subject:

Yesterday evening we lent me the book "ecological insulation" by jp oliva
on page 194 he briefly talks about the low emissivity.

I quote : "this type of glazing has very little impact on the penetration of light and especially solar heat and effectively opposes its exit in the other direction which gives it a very good energy balance."

So from point of view we would tend to say must put everywhere ....

Then in the next paragraph he explains that for health reasons the low emissivity is justified especially in the north and possibly east and west. It blocks uv necessary for the human body. It all depends on the occupants also if it is people who stay locked up and work inside or if it is a farmer who is always outside for example.





So with all this I still don't know if the gain / loss ratio and better in low emissivity or double glazing only argon.implicitly on the book by jp oliva we will understand that no but no certainty ... I continue my research but it will soon I will have to order ...

[hic]

Hello

in a straw house that I am starting to build would it be interesting to put glazing with just argon gas to allow the infra red of the sun to heat the interior.

What you will need to know is whether the IR input outside will be greater than the heat loss by radiation from the inside but that I have no idea.
My heating will be initially just wood then solar floor probably thereafter

do you have any idea on the question ????

Hi lolus
And why not a simple glazing?
Double glazing blocks 2x more infrared
(with or without argon),

- "with a ladle"
about 50% of thermal energy
the double glazing is absorbed (and heated)

At night, single glazing can be insulated with a layer of insulation
During the 1 or 2 winter months, a French window becomes almost useless,
why not condemn it with a 10cm insulating plate
All this for a ridiculous cost price
Catch up

[Did67]

Yesterday evening we lent me the book "ecological insulation" by jp oliva
on page 194 he briefly talks about the low emissivity.

I quote : "this type of glazing has very little impact on the penetration of light and especially solar heat and effectively opposes its exit in the other direction which gives it a very good energy balance."
...

1) I don't have this book. But I had asked myself the question.

2) In theory, I understand the principle: re-entry of energy in the form of visible radiation (light) + UV + also some IR.

The light is "captured" by the ground, walls, etc ... Which in the evening, radiation especially from IR (yes, we "see nothing" except thermal cameras).

So a treatment blouqing essentially the IR would reduce little the "inputs" but much the "outputs" ...

So in theory, I understand.

3) But my observation on my Velux led me to conclude the opposite. I swear the feeling of warmth is not at all the same across Velux in the summer.

In super good weather, if I close the skylight, I can hardly feel the heat. If I open it parallel to the rays of the sun, it "hits" ... The temperature of the room does not change the time of the test.

Are there multiple systems? Several surface treatments and Velux he retained a system which "does not let in" (because this is the big complaint against Velux) ????

I cannot answer or resolve this contradiction.

Last points: shutters certainly. But I also day, while the light and heat enters the house, in very cold weather, the house at the same time, loses heat (by conduction, hence double glazing + argon) but also by radiation. And there, we do not vapas close the shutters!

Very last point: it is more effective to "block out" the radiation inside the house rather than outside. So big curtains with possibly an aluminum film to be drawn in the evening!

[minguinhirigue]

fthanron, here is a "non-commercial study on triple glazing in France", it is quite categorical on southern triple glazing: not terrible in France (even when there are 50% masks on the south facade and in a climate of mountain) facing a very good double glazing with reinforced insulation .: http://www.ddmagazine.com/20090115857/G ... trage.html

For the question of low-emitting glazing, I will send you some data tomorrow morning.

[lolus]

Isn't there a glazing specialist here ????

It is true that this subject is not so obvious as it may seem.

When I talk to a window seller of course they know nothing about it and know quedal ....

I can imagine what you saw did67
My father found the same thing with a friend with a bay window facing south in the spring and he had the feeling of cold behind while the sun was beating down on it and it was weak emissivity .....


What I do not know is if we lose a lot in insulation with argon double glazing alone compared to the low emissivity






Otherwise the idea of ​​simple glazing yes but where I live at 800m altitude even during the day I will have more loss than gain especially on bad weather days and I do not want to live cloistered in the dark .... and then even in the off season I will have to close the windows as soon as there is more direct sun so same result ...

I think that simple glazing will be better for a cloud wall that can be closed at night with an insulating shutter

[Dudule]

So for me, "the best solution", it depends:

- if I want to prioritize the "gain of calories" (in winter): opt for a maximum of insulation (therefore triple argon glazing) but to low emissivity; but in this case, watch out for radiation in summer (I know what I'm talking about, I have about 25 m² of south-west facing French windows, with "normal" double glazing) - the question must then be dealt with ( screens, shading, shutters ...) ...

- if I want to prioritize the freshness in summer (it's my choice for the attic): double or triple glazing + low emissivity ... But I have to heat more in winter (on sunny days, I don't capture as much radiation - and it feels on the skin; that's what I said; it also feels on the floor, which heats up less).

I think there are several types of low emissivity:
summer: the heat does not come in but can come out,
winter: the heat enters but does not come out,
4 seasons: does not come in and does not go out.

On the other hand I believe that low emissivity is mandatory according to the RT or I do not know which regulation.

In addition it seems that the low emissivity prevents fogging on the windows !!!

[dedeleco]

Completely agree with Hic and with:
http://www.ddmagazine.com/20090115857/G ... trage.html
to read carefully:

And then, it should be noted that triple glazing is a very elaborate technology, which makes no sense, says Armand Dutreix, if the rest of the building does not match: "Wanting to change your windows with triple glazing on a house or a building whose thermal performance is not up to date on all of its other components makes no sense, neither economic nor environmental. "
In France, there is too much sun to justify triple glazing (without mask) elsewhere than to the north.
In Marseille, a triple glazing without mask facing south has a lower energy balance in winter than simple glazing.
Only a full north orientation has an energy balance slightly favorable for triple glazing, if you are not in the Mediterranean region

and even real scam by salespeople who change the glazing, windows and doors before the main insulation of the walls and roof spaces !!

Put figures on heat loss by the walls compared to the windows (surfaces by losses) !!
Do not trust at all the salespeople who only think about their end-of-month bonus !!
Do not throw your money in the trash !!
Put or save it to insulate the walls first !!