Aluminum foil in the wall

[useless]

IR radiation = heat radiation, are we agreed on this?
If aluminum foil demonstrably reflects heat radiation, even behind building material.
Where do you think it should go?

I did say that the IR radiation does not reach the foil behind the wall.

Sure, from a purely physical standpoint, you could calculate that it makes a marginal difference. Heat conducted through the panel radiates out the back and is reflected back, so less heat is conducted through the board.
But in practice, it has very little significance compared to other energy-saving measures.

 

[Tomture61]

I did say that the IR radiation does not reach the foil behind the wall?

Sure, purely from a physics standpoint, you can calculate that it makes a marginal difference. Heat conducted through the panel radiates on the backside and is reflected back so that less heat conducts through the board.
But in practice, it has very little significance compared to other energy-saving measures.

There is a very small tradition of using aluminum foil as a complement to thermal insulation in Sweden, yes.
I have a very well-insulated house that becomes very warm in the summer.
Energy is indestructible.
Even IR / thermal radiation.

 

[useless]

Energy is indestructible.
Even IR / heat radiation.

That's not quite correct. The IR/heat radiation is absorbed by the material it hits.

 

[Tomture61]

That's not quite right. The IR/thermal radiation is absorbed by the material it hits.

So you mean that the heat in a building is absorbed by materials in the building and never leaves said materials.
Then I must quickly shut off the heat in the house, things might start burning after a while.

 

[useless]

So you mean that the heat in a building is absorbed by the material in the building and never leaves it. Then I must quickly turn off the heat in the house, things might start to burn after a while.

No, that's not what I mean. But the heat radiation will not reflect around the room indefinitely. Most of it is absorbed by the material (depending on how good it is as a reflector). Some of it radiates back into the room from the heated material and some is conducted through the material out through the wall.

But the main question was how effective an IR-reflective material is behind a 20 mm wood panel, right?

 

[Tomture61]

No, that's not what I mean. But the radiant heat will not reflect around the room indefinitely. Most of it is absorbed by the material (depending on how good it is as a reflector). Some radiates back into the room from the heated material and some is conducted through the material out through the wall.

But the basic question was how effective an IR-reflective material is behind 20 mm wood paneling?

Alufolie is probably more effective in a tropical climate.
There's a larger dose of heat there.
Additionally, there should be an air gap on the side you want to reflect the heat.
Takes more space from the building.
But claiming that alufolie doesn't reflect radiant heat is completely wrong.

 

[useless]

But claiming that aluminum foil does not reflect heat radiation is completely wrong.

I have only claimed that aluminum foil behind a wooden panel is an inefficient way to minimize energy consumption.

 

[GK100]

Aluminum foil is probably more effective in tropical climates.
There's a higher dose of heat there.
Additionally, there should be an air gap on the side where you want to reflect the heat.
It takes up more space in the building.
But claiming that aluminum foil does not reflect radiant heat is completely wrong.

I think you'll get further if you start from the temperature of the source of the radiation and combine a bit with Stefan-Boltzmann's law. The aluminum foil is obviously an excellent reflector, but the difference behind a room-temperature wooden panel and, for example, what was mentioned about 1970s high-temperature heating elements with foil behind is already significant, even though both should be seen as marginal overall.

 

[cpalm]

As mentioned, we think we should drop the IR/heat track.
This is a vapor barrier, nothing else.

 

[Thomas_Blekinge]

Aluminum foil is certainly more effective in tropical climates.
There is a greater dose of heat there.
Additionally, there should be an air gap on the side where you want to reflect the heat.
It takes more space from the building.
But claiming that aluminum foil does not reflect thermal radiation is completely wrong.

You don't seem to want to understand. The foil of course reflects IR radiation but only that which reaches the foil. If the foil is behind the wooden panel, the radiation never reaches it and therefore cannot be reflected.
It's like a mirror that can reflect light, but if you cover the mirror with a thick curtain, it no longer does.

 

[Tomture61]

You don't seem to want to understand. The foil obviously reflects IR radiation, but only the radiation that reaches the foil. If the foil is behind the wooden panel, the radiation never reaches it and therefore cannot be reflected. It's like a mirror that can reflect light, but if you cover the mirror with a thick curtain, it no longer does.

So your point is that a wooden panel/drywall cannot transport heat through itself. Why did I build the house with minimal pathways for the conduction of heat energy? 🤔🤪 Wasted money....

 

[Thomas_Blekinge]

So, your meaning is that a wood panel/drywall cannot transport heat through itself.
Why did I build the house with a minimum of pathways for conducting heat energy?
🤔🤪
Wasted money...

Heat can be transported in three different ways:
1. Conduction, e.g., through solid materials. In house building, materials are chosen that transport heat through them as little as possible, such as polystyrene, mineral wool, etc. Cold bridges of materials that easily transport heat are avoided.
2. Convection, which is when heat is transported by a moving medium (air, water) that carries the heat with it. This happens over a warm radiator or between two panes in a window. In mineral wool, the gaps are so small that convection cannot occur. When using a fan to transport heat, it is also convection.
3. Radiation. Heat radiation is invisible light with a wavelength >700 nm, it goes through glass and foil but not through opaque materials, like drywall or wood paneling.
These three methods behave completely differently, and they shouldn't be mixed up.

 

[Tomture61]

Heat can be transported in three different ways:
1. Conduction, e.g., through solid materials. In house construction, materials that transport heat through themselves as little as possible are chosen, such as styrofoam, mineral wool, etc. Cold bridges of materials that easily transport heat are avoided.
2. Convection, which is when heat is transported by a medium (air, water) moving and carrying the heat with it. It happens over a warm radiator or between two panes in a window. In mineral wool, the gaps are so small that convection cannot occur. When you use a fan to transport heat, that is also convection.
3. Radiation. Heat radiation is invisible light with a wavelength >700 nm, it passes through glass and plastic film but not through materials that are opaque, such as plasterboard or wood paneling.
These three methods behave completely differently and should not be confused.

It's tricky that you have also written in this thread that heat cannot be transported through the surface material in a wall.
Energy is something that cannot be killed, only spread.

 

[Thomas_Blekinge]

that heat cannot be transported through the surface material in a wall.

Where have I written that?

 

[Tomture61]

Where did I write that?

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