What Are the Two Basic Types of Insulation & How Does Each Type Work?

Batts

• Batt, or blanket, insulation is the installation of pre-cut pieces of insulating material. The batts come in standard sizes or on a roll that the homeowner can cut themselves, particularly useful if the attic has an irregular shape. Batts can be made from a variety of materials. The most common are glass fiber, mineral wool and polyester. This type of insulation works by preventing heat escaping through the structure of the building. It can also serve to dampen sound, providing acoustic insulation as well.

Blown-in

• Blow-in, or loose-fill, insulation is material that has been finely shredded so that it can be blown or poured into a space, where it gradually hardens. It too works by suppressing the loss of heat as it travels through the interior walls and ceilings of a house. The primary types of blown-in insulation are cellulose -- made from recycled paper treated with fire-resistant chemicals -- glass fiber and mineral wool. Blown-in insulation may also come in the form of polyurethane or plastic foam, which sets in seconds.

Choosing

• The type of insulation a homeowner chooses -- either batts or blown-in -- is likely to depend on the dimensions and accessibility of the space they wish to fill. Homes with easily-accessible attics and exposed wall spaces can be fitted with batts, whereas blown-in insulation is preferable for irregular spaces and attics lacking convenient access. Batts should be used where there is a lot of wiring and air conditioning equipment in the attic as it will restrict their effectiveness less than blown-in, while blown-in is preferable if there is old insulation already installed: laying new batts over old batts is not very effective, whereas blown-in insulation gets between the old batts.

Other Types

• A third form of insulation is rigid board insulation. Made from glass fiber, polyester or polyurethane, these boards can be cut to standard sizes, although can be difficult to cut precisely to fit irregularly-shaped areas. Rigid board insulation tends to be more expensive than batts or blown-in, and is therefore less common in homes.