Foil Insulation R Value

Products with foil facing help the panels resist moisture vapor.

Foil insulation r value.

R value is a term to describe how quickly heat will pass through or be absorbed by a product. This material offers the highest r values about r 6 to 6 5. Other materials may only have a fifty percent increase in r value when their thickness is doubled. 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.

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. The astm c236 1224 tests that determine a products r value yield the following results for rfoil reflective insulation. This testing to designate an r value only applies to conductive heat flow not radiant heat flow. Heat flow down r 10 6 heat flow horizontal r 6 8 heat flow up r 5 3.

Working with home insulation boards insulation panels typically come in 4x8 foot sheets. Polyiso is typically used with a foil facing and it has an r value of 7 0 to 8 0 per inch of thickness. The sheets themselves are not created equally. 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.

The foil facing also makes it very easy to seal with good quality foil faced tapes. Each sheet is created with different r value ratings. 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. These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation.

An r value is a measure of an insulation product s resistance to thermal heat transfer. 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. Most metallic bubble wraps are about an r 1. The r value is in essence the measurement of an insulation sheet s ability to resist heat flow.

What is the r value or r rating of radiant barrier foil 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. Smaller sizes are also available. It provides about r 5 per inch.