Foil Insulation R Value

The r value is in essence the measurement of an insulation sheet s ability to resist heat flow.

Foil insulation r value.

Products with foil facing help the panels resist moisture vapor. Basically r values range from 1 5 to 7 and the higher the number is the more effective the insulation sheet is at increasing thermal efficiency and thereby insulating your home. These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation. For example if you have a type of insulation that has an r value of r 5 per inch of thickness you will need a depth of 6 inches of this insulation installed in your attic to reach r 30 if you live in zones 2 or 3.

The astm c236 1224 tests that determine a products r value yield the following results for rfoil reflective insulation. Most metallic bubble wraps are about an r 1. It s a measure of how long it takes a heat absorbing product to absorb 100 of its potential and begin to transfer that heat out the other side of the product. The sheets themselves are not created equally.

Triple pane windows with low e surfaces perform better than a triple pane window without low e surfaces because of the reduction of radiation low emittance across the air spaces. Polyiso is typically used with a foil facing and it has an r value of 7 0 to 8 0 per inch of thickness. Each sheet is created with different r value ratings. The foil facing also makes it very easy to seal with good quality foil faced tapes.

Worth mentioning to get the equivalent r value to what the manufactures claim on the packaging the installer has to use spacers under the insulation to keep the prescribed air gap between the ducts and the foil. This testing to designate an r value only applies to conductive heat flow not radiant heat flow. An r value is a measure of an insulation product s resistance to thermal heat transfer. Working with home insulation boards insulation panels typically come in 4x8 foot sheets.

Smaller sizes are also available. Heat flow down r 10 6 heat flow horizontal r 6 8 heat flow up r 5 3. This material offers the highest r values about r 6 to 6 5. Just as the absorbency of a raincoat is unrelated to its ability to repel water the r value of rfoil does not fully measure its ability to insulate and redirect heat energy.

R value is a term to describe how quickly heat will pass through or be absorbed by a product. Air inherently has an r per inch value of 5 6 and is an excellent insulator when radiation and convection are controlled. As a foil faced polyisocyanurate foam insulation enerfoil tm s r value actually more than doubles when it is twice as thick as you can see from the chart above. It provides about r 5 per inch.