Would this work on a house?

[TexasR.N.]

So I was listening to a commercial for a radiant barrier. They mentioned aluminized blah blah blah and it got me to thinking (I realize this might sound silly) but, if I put aluminum foil in between the studs before I put up my insulation would that be effective at keeping additional heat out of the house? I am I just smoking crack here or does this have some potential as an inexpensive energy saver?
Craig

[jfines@cox.net]

It would be better to have the foil on the outside of the studs. Keep the heat off of the insulation.

And it is being done here is AZ. Of course it is an upgrade.

[choctaw]

It should work, however the best place for the radiant barrier to go is on the outside of the studs, before any type of brick-rock-wood-metal veneer is put on.
Now as far as the inside is concerned you can put a sheet of visqueen (thick plastic) on the studs after you insulate this would help with air and vapor.

[exitwound]

I would think as long as in went in before the insulation it would seem like a pretty good idea.

[Mike6176]

Originally Posted by choctaw

It should work, however the best place for the radiant barrier to go is on the outside of the studs, before any type of brick-rock-wood-metal veneer is put on.
Now as far as the inside is concerned you can put a sheet of visqueen (thick plastic) on the studs after you insulate this would help with air and vapor.

Just be sure if you do both that you have some way that water vapor that is trapped in the wall during construction can get out.... Otherwise you'll have a soggy mess inside your walls.

[Shep1824]

Originally Posted by Mike6176

Just be sure if you do both that you have some way that water vapor that is trapped in the wall during construction can get out.... Otherwise you'll have a soggy mess inside your walls.

I agree. You do not want double vapor barriers because there is no way for any vapor or moisture to escape. Kraft paper on insulation acts as a vapor barrier and your Tyvek or house wrap acts as one as well. Any more than that you are looking for trouble. You could put the foil in place of the Tyvek so you do not have the double barrier.

[choctaw]

Originally Posted by Mike6176

Just be sure if you do both that you have some way that water vapor that is trapped in the wall during construction can get out.... Otherwise you'll have a soggy mess inside your walls.

Correct, however I don't think you could get it that airtight, we have been doing this for quite a few years with no ill effect. I think the best way would be to put OSB with foil applied to the outside then the vapor barrier on the inside, don't you agree Mike?

[TexasR.N.]

Well it's too late to put it on outside as most of my metal siding is up. Still it would afford me some extra help putting it inside right? The outside is wrapped with Tyvek. I realize this doesn't effect the radiant heat, just mentioning it because of the moisture comments.
Craig

[choctaw]

Originally Posted by HappeetxnR.N.

Well it's too late to put it on outside as most of my metal siding is up. Still it would afford me some extra help putting it inside right? The outside is wrapped with Tyvek. I realize this doesn't effect the radiant heat, just mentioning it because of the moisture comments.
Craig

The Tyvek will breath a little, so I would put the vapor barrier on the inside. The radiant barrier needs to be on the outside.

[Mike6176]

Originally Posted by choctaw

Correct, however I don't think you could get it that airtight, we have been doing this for quite a few years with no ill effect. I think the best way would be to put OSB with foil applied to the outside then the vapor barrier on the inside, don't you agree Mike?

I know that Solar Board the manufacturer's instruction say to put the foil to the inside. Why I'm not sure, it doesn't make sense in my head.

Craig, I don't think Alumimum foil would be very cost effective way of lining your walls. Would it help? Yes to a degree but I think you would spend a fortune in Aluminum foil for not that great of savings.

Vapor Barriers - it depends on where you live as to where you put it. Without getting too detailed. Water vapor wants to go from higher pressure to lower pressure. In the South, we are more hot than cold. Hot air can hold more water vapor than cold. Therefore most of the year, the water vapor pressure is higher outside so you put your vapor barrier on the outside of the studs to protect your insulation. The opposite is true for more northern climates. Typically its colder and drier outside than it is inside. The whole point of the vapor barrier is to help protect your insulation from getting wet.

If you double up and put it on both, the potential for water to collect inside the wall is there. Depending on when the walls were installed, would greatly influence the risk.