Heat flows naturally from a warmer area to a cooler area. Heated air from inside your home wants to escape into the cooler attic in the winter, and, in the summer, heat from the attic will flow into the air conditioned living spaces of your home. This process of energy transfer is called convection.
Energy Star estimates that the average homeowner can save up 20% annually in heating and cooling costs by sealing air leaks in their home. Common air leaks occur in the attic around recessed lighting and openings for duct work. Sealing attic-to-home air leaks is important, since most insulation does not stop all air flow.
Air sealing your attic can help prevent drafts and the movement of energy as well as moisture. Wet insulation doesn’t insulate well. Also, the build up of moisture can cause mold and mildew to grow and can cause damage to your home. Your insulation works best when air is not moving around it. You’ll want to seal air leaks with caulk or foam before you add more insulation.
A home energy audit can find where air and energy are escaping. You can contact us for a professional inspection of your home or you can do an energy audit yourself.
R-value measures how well insulation resists heat. The higher the R-value, the better the material is at insulating. R-value is determined by the type of material, its density, and its thickness when installed. Adding more insulation to your attic can increase the R-value, making your home more comfortable and saving you money on heating and cooling costs.
The recommended R-value for most parts of the country is R-38, according to Energy Star. Depending on the insulation type, this is about 12 to 15 inches of insulation. However, recommendations for different regions vary depending on climate and frequency of severe hot and/or cold temperatures.
Can you see the wooden joists on your attic floor? If so, it is recommended that you add more insulation. You have a few options.
Fiberglass blanket insulation usually comes in batts or rolls, which are fitted or rolled out between joists in the attic. It is available with and without vapor barrier or it can come completely encased in plastic. It is recommended that you use rolls with no barrier or plastic if you are adding it to existing insulation. To achieve the recommended R-38 you’ll need to install approximately 12 inches of fiberglass blanket insulation. This should run you about $0.55 to $0.60 per square foot.
Loose fill insulation works well for oddly shaped areas. Small pieces of insulation are blown into walls and attics using special equipment and conform to the area that is being filled. You may consider hiring a professional who is experienced with this equipment to install loose fill insulation so as to avoid covering vents or electrical elements which could be a fire hazard. The recommended R-38 may cost you approximately $0.80 to $1.00 per square foot.
The most common types of blown insulation include cellulose, fiberglass, and mineral wool.
An increasingly popular choice for attic insulation is spray foam. This polyurethane foam is sprayed onto attic surfaces and expands to fills cracks and crevices, sealing your attic as it insulates. There is no settling or moisture to worry about. Installation should be left to trained professionals. Spray foam insulation is more costly than other options at $1.30 to $3.50 per square foot, roughly $2,400 for a 1,600 square foot home (triple this if you need 3" of spray foam). However, you will see payback over time in energy savings, and spray foam can also contributes to your home’s resale value.