You probably don't think about insulation very much. It's that stuff between your walls and under your roof: out of sight, out of mind. However, if you understand how insulation works and the differences between insulating materials, you can make your house more green while saving a lot of green on your energy bills.
All types of insulation share three things in common: they keep the heat inside during the winter, they keep the heat out during the summer and they are rated by R-values, which measure their levels of thermal conductivity. The higher the R-value, the more protection the product provides. However, your roof needs more protection than your walls due to the simple theory that heat rises. Insulation is also made in many shapes and textures so that it can accommodate a variety of spatial conditions. Here are four common types of insulation:
The most common and cheapest type of insulation is batt insulation, a fluffy sheet that comes in long rolls. It's usually pastel, like cotton candy, and you want to reach out and touch it. But be careful; batt insulation is made from glass fibers. It fits nicely between studs and around beams in your walls and ceilings.
Rigid foam insulation looks exactly how it sounds, kind of like Styrofoam. It has a much slimmer profile than batt insulation and is more effective by the inch. Foam boards are used on exterior walls, such as behind vinyl siding, or in ceilings, but they must be covered with drywall for interior applications. And since this insulation type is rigid, it may require cuts to accommodate plumbing or electrical conduits, which lowers its insulating capacity.
Loose fill insulation might remind you of confetti. It's blasted by a special machine into a wall cavity, making it a good choice for home renovations, especially for older homes. Loose fill may be made of cellulose, fiberglass or even wool. Sprayed foam is another great insulation option for existing walls and provides twice the insulating value as batt insulation, but expect to pay more upfront.
Specialized insulation products address specific situations: a fiberglass material is made to wrap the ducts of your heating and cooling system, and foam rubber sleeves insulate exposed plumbing pipes to prevent them from bursting in cold weather or otherwise releasing unnecessary heat.
Insulation may seem like a snooze-inducing topic, but padding your walls and roof can save you a bundle on heating and cooling costs. Just be aware that not every insulation is created equal: you wouldn't wear a t-shirt out in the middle of winter, so don't leave your house under-dressed.