According to the Department of Energy, your home should be insulated from top to bottom. Proper insulation can help reduce your household energy costs and the strain on your HVAC. So, let’s take a look at the top of your home and the different attic insulation types.
Where to Insulate
Before insulating, make sure you seal all air leaks. You can find these in the form of seams and cracks. Air leaks make it difficult for the insulation to do its job. Sealing air leaks and having proper insulation are the first steps to creating your energy efficient home.
If you have an unfinished attic space, you should place insulation between and over the floor joists. Doing this will help keep the conditioned spaces below at comfortable temperatures. With air distribution systems in the attic, you should probably insulate the rafters as well. This will help to insulate the air ducts. Attic access doors and knee walls should also be insulated with something like an attic tent.
Loose-fill and Batt Insulation
The most commonly used attic insulation types are loose-fill and batt insulation. Loose insulation is in the form of loose particles that are blown into the open attic or enclosed cavities, such as walls. Batts are prefabricated chunks of insulation made from loose materials. They come in rolls and are fairly easy to install. Batts are usually a perfect fit for small spaces, such as between the wall studs or floor joists.
Loose-fill and batt insulation are typically made out of materials like fiberglass, cellulose, or mineral wool. You want an R-value of at least 30 for your attic, which is about 11 inches of fiberglass or mineral wool and 8 inches of cellulose. If you have less than that, you may want to consider adding more.
Fiberglass is made of fine pieces of glass. Insulation batts made of fiberglass are like floppy blankets and must be stapled in place. They absorb moisture easily and can sag out of place when wet. Fiberglass can also be irritating to the skin and lungs, so protective gear is needed during handling.
Mineral wool is typically made of natural minerals, like rock or iron. It doesn’t require any added chemicals to be fire, water, and insect resistant. Mineral wool batts are formed into a blanket, just like fiberglass but are denser and less floppy, so they keep their form better. Mineral wool has a slightly higher R-value and is usually more expensive than fiberglass.
Cellulose is made of recycled paper and chemicals are added to make it fire and insect resistant.
Spray Foam Insulation
Spray foam is usually liquid polyurethane and latex which expands once it comes in contact with air. It is best suited for coating surfaces and sealing insulation in hard to reach spaces. You can use spray foam in caulking jobs. Even though it is weather-proof, it is the most expensive way to fill large voids. You should call a professional to install it for bigger projects.
Radiant and Vapor Barriers
Radiant barriers insulate against radiant heat, protecting the existing insulation from heating up. They can be very effective, particularly in hot climates, reducing energy bills by up to 10-17%.
Also worth mentioning here are vapor barriers. By using vapor barriers, you can prevent moisture, mold, and rot from occurring.
Want to find out more?
Check out our education center for more information about attic insulation, or contact us directly with your questions about attic insulation types.