Fiberglass insulation is commonly found in residential or commercial construction in floor systems, walls, ceilings and rafters. Fiberglass is generally pink or yellow in color; it is also very itchy upon skin, eye or throat contact. Fiberglass is made by melting glass and drawing off the molten material into fibers. The fibers are bound together with organic resins to form batts or blankets.
While fiberglass is commonly used, it is one of the least effective insulations on the market. Fiberglass can be effectively used only if great care is taken during installation, and extra measures are taken to form an air-barrier. During installation appropriate notching around electrical boxes, light fixtures, piping, ducting and wiring must be performed carefully. Any compression or poorly cut to fit fiberglass batts will quickly result in a lower overall insulation R-value.
Fiberglass insulation also has no ability to stop air movement; by allowing air to move freely through its fibers, energy is lost through convection. Fiberglass is last on the list to be chosen in today’s efficiency needs.
Insulation R-Values Per Inch
|Fiberglass batts or blown
Icynene (low density spray foam)
Expanded Polystyrene (white)
Extruded Polystyrene (blue/pink)
Polyurethane (spray foam or board)
Polyisocyanurate (spray foam or board)
|2.4 – 3.0
3.3 – 4.0
3.6 – 4.2
5.8 – 6.8
5.6 – 7.6