“Insulation is one of those building products that you never see because it’s usually covered up by something else…but if you don’t have enough, or if it is installed incorrectly, you’re wasting energy and paying more for heating and cooling than is necessary.
There are a number of insulation products you can use to prevent energy loss – but realize that insulation is only one part of a two-step approach to energy efficiency. The other part of the plan involves sealing all of the holes, cracks or openings caused by pipes, wires, chimneys or anything that creates an opening in a wall, ceiling or attic floor.
These openings allow interior air to escape to the unconditioned (not heated or cooled) space that surrounds your home. The sealing process is called “air sealing”, and requires silicone caulk and expanding foam that comes in a can. While easy, it requires attention to detail because many insulation products do not stop moving air. If you plan on insulating, be sure to attend to air sealing as well.
WHERE TO INSULATE: Place insulation in any area that separates your heated and cooled living spaces from areas that are not heated and cooled, including
- Cathedral ceilings
- Sidewalls, walls between the living area and an attached garage
- Floors over unheated basements
- Floors over crawl spaces
- Foundation walls
INSULATION MATERIALS: Effectiveness is measured by R-Value – The “R” stands for resistance to heat flow. The higher the R Value, the better. It is important to match the insulation to the application as well. Fiberglass insulation has an R Value of about 2.8 to 4 per inch. Some foam panels have R Values of 7 or 8. But you can easily find fiberglass batts or blankets that are 12 inches thick and designed for use as attic insulation, providing over an R-40. Standard foam panels only come in one-half to two inch thicknesses.
Some products area easier to install than others. Fiberglass batts simply roll into place. They are manufactured to fit snugly between ceiling joists and wall studs. When installing any insulation, it is important that the product be places flat against the surface you are insulating. Any air space under the insulation or gaps around the edges will limit the effectiveness of the product
Below is a brief look at the R-Values of common insulation products.
Fiberglass, Mineral Wool – 2.8 to 4
Cellulose – 3 to 3.7
Foam Boards – Polystyrene: 4 to 5, Polyisocyanurate: 6 to 8
Spray-On Polyurethane – Open Cell: 3.6 to 4.3 Closed-cell: 5.6 to 6.8
For charts with more detail, visit the websites of any hardware or home materials store.
SOURCE: Fran Donegan for realtytimes.com