Energy Efficient Insulation – Elements for Greenest Use

March 20, 2009 by  
Filed under Energy Efficiency

One of the best ways to make your home a place for green, sustainable living is hidden behind your walls. A major factor in the energy efficiency of your home is the quality of your insulation. Not all kinds of insulation are created equal. Three key variables in determining how efficient your insulation is are the R-value, type of insulation used, and where it is located.
The R-value of insulation determines how effectively it keeps heat in during cold temperatures and out during hot temperatures. The higher its R-value, the better insulation is at keeping your home energy efficient. It is also important to consider that without proper installation your insulation may not be reaching the R-value intended by the manufacturer. To get the most energy efficient results, you need to choose the right type of insulation and make every effort to ensure that it is correctly installed. Though it sounds like a great idea, it’s not possible to raise the R-value of your insulation by doubling it up.
Of all the different types of insulation available for residential use, fiberglass and cellulose are most common. Fiberglass comes as loose fill or batting (narrow blankets sold in rolls). Fiberglass batts, commonly used in attics, walls, and floors, are one of the best types of insulation for achieving lasting energy efficiency. They hold their R-value longer than cellulose and won’t settle. One disadvantage is that batting needs to be cut carefully to fit around wires and electrical boxes, and haphazard installation subtracts from the R-value.
Cellulose insulation is sold as loose-fill and requires a blower for installation. It is made from recycled paper, which would seem to make it eco-friendly, but the material is treated with flame retardant and pest repellant chemicals that may not be environmentally safe. It is generally less expensive than fiberglass and easy for the average homeowner to pick up at hardware stores or lumber yards. Disadvantages of cellulose are that it settles as much as 25% over time, which lessens the R-value. Also, it should not be used in humid climates because it absorbs moisture. Accumulated moisture increases the risk of washing out the fire retardant and corroding wiring or siding.
Once you know what type of insulation is best for your home, determining where to install it is also important. Insulation in a home’s foundation and floors increases the energy efficiency far above homes that only have insulation in the walls and ceiling. It is still possible to insulate these areas after your home is built. However, as you would expect, it is easiest to insulate these areas during initial construction.

One last thing. Don’t count on your area’s building code requirements to establish energy efficiency with your insulation. These are often nominal requirements for the region that have not set a bar for sustainable living.

If you want to have an energy efficient home, strive to far exceed the R-values set by your local area requirements, especially in exterior walls and ceilings. Insulate your home’s foundation and floors if possible. Look for the best material for your climate that has the greatest R-value within your budget, and you will be well on your way to green living.