Insulating Paint Additive

He could try a proper experiment.. take a box well insulated on all but one face. Put in a 40w lamp. put a sheet of metal on the remaining face measure the temp in the box after it has stabilised. repeat after painting metal sheet See if there is any change in the temperature differences in each case.

Actually, in that report is the R-value of 9.5mm plasterboard + surface resistance as 0.136m^2K/W, so a difference of only 0.063m^2K/W. This is the equivalent of (0.063m^K/W * 0.04W/mK) 2.3mm of polystyrene.

As others in this thread have pointed out, it's possible that some or all of the increase in surface resistance could be due to increased albedo.

I wonder if it's made by the same people as make Tri-Iso multifoil loft insulation?

But the paint by it self will make a difference so you need another metal sheet painted but with out the magic additive.

Only if you are comparing one paint to another. It allows you to calculate the heat flow and you can measure the temp difference. I think it safe to ignore the thermal resistance of a thin sheet of metal.

No you are comparing unpainted with painted + magic additive. How do you

If the first sheet was painted sans additive and the other was painted with additive that would be OK but I got the impression the first sheet was unpainted.

I read a good layman's view of the technical issues with misleading R- values (including multifoils) here:

That is illogical as the additive doesn't work without paint, you can't compare the additive on its own.

It will tell you how well the paint with the additive performs.

Yes, but how do you know that any difference is down to the paint or paint

• additive when you only compare paint + additive against unpainted.

But not if the paint on it's own will perfom just as well.

Well as I don't expect much difference I don't think it matters.