Radiant Barrier Walls with Rigid Foam Insulation

[HomeEnergyNow]

"green" Surely you know all THREE layers of garb you are puttin on before even siding the dang thing, are all majority petroleum.......how is that green? If it is "green" as in energy savings, then could you try to show us exactly what those multiple layers on the wall will save per year in energy, see if it ever touches the amount of energy used in making/shipping/installing those products?

[MattRisinger]

@HomeEnergyNow Yes we do need to be thoughtful about our use of petro products in our houses, however when we build houses to last 75-100-150 years the amount of energy saved certainly justifies the use of some resources at the beginning. We don't know what energy prices will be in 2 years let alone 15 years so building a very efficient house makes financially and from a stewardship perspective. -Matt Risinger

[lexichronicle2]

You guys should check out the Passive House ideas from Sweden and Germany. They line the house with 9" of polyurethane, so it's basically a super insulated airtight box. All of the heating (in your case cooling) comes from an air conditioning unit which keeps the moisture levels in check as well. Fresh air comes in through a heat exchanger, so the thing takes barely any energy to heat (cool in Texas) yet is still full of fresh air. It's triple glazed, as well.

[AtticFoil]

Matt, nice video.

Your absolutely right on this one. Heat flow is all about the difference between the inside and outside temperature of an object. The sheathing behind a West or South facing wall can easily exceed 120 degrees since the brick can get over 150 degrees. With a radiant barrier in the assembly the sheathing (or foam board in this case) should be just a few degrees above ambient temperature. Drop the delta T and reduce the heat flow. It's that simple.

Ed

[MattRisinger]

@AtticFoil Thanks for your comments. Matt