Bubble Foil Insulation

Understanding Bubble Foil Insulation

Heat moves from warm to cool regions these are three ways:

1) Conduction: Heat flow through a material

2) Convection: Heat flow transferred by the movement of air

3) Radiation: Electromagnetic transfer of energy through space

What is R-value?

R-value is an assigned number derived from a specific testing procedure to determine a materials assembly?s resistance to conductive heat transfer. The higher the R-value, the more resistant a material or assembly?s is to conductive heat transfer.

R-values for reflective insulations are dependent on two (primary) criteria:

1) Heat flow direction

2) The amount of air space in a closed cavity on the reflective side of the product in the assembly

What is a reflective Insulation?

A reflective insulation is a material (or assembly) that reduces the rate of radiant heat transfer across air spaces by use of one or more highly reflective surfaces. In the same way fiberglass insulations provide benefit, reflective insulation reduces conductive heat transfer. When a highly-reflective material is installed, in conjunction with an air space, it provides a measurable R-value benefit.

Why are air spaces required?

For either a reflective insulation or a radiant barrier, an air space of a minimum thickness is required on the reflective side of the product. The reflective insulation benefit is derived from the interaction of the highly reflective surface with the air space. If the reflective surface is in contact with another building material, it becomes a conductor (transmitting the energy by conduction)

Why do you need spacers (for certain applications)?

Spacers are used to provide an air space where one is not present.

What if there is no air space present on either side of the product?

No air space = no reflective insulation benefit  (An R-1.1 is provided from the product itself for reflective/double bubble material.)

If you install two layers of a reflective insulation, does the R-value double?

With multiple layers of product and air spaces between each layer, enhanced performance will be gained. If the product is simply ?doubled? (with no air space between the layers), a very minimal benefit is obtained (R-1.1 (per layer) for reflective/double bubble product).