What an enticing topic, “Insulation Choices.” It certainly portends of a page turning thriller, doesn’t it? Curl up in bed and prepare to be mesmerized! Okay, so it is a dry and rather bland topic. However, when it comes to improving the energy efficiency of your home, there is little that provides a bigger impact than insulation.
Today, we have three basic insulation choices; loose (or blown in), blanket (roll or batt) and foam (sheet or spray on). Each has its own set of benefits and its related costs.
Perhaps the most familiar is the blanket (roll or batt) style of insulation made from fiberglass. It is found in a variety of thicknesses and is suitable for installation between studs and joists. In new construction and renovation of previously unfinished spaces, it is one of the easier types to install. And, when used in floor joists, it is also easy to remove if you need to access wires or plumbing behind it for maintenance reasons. On the negative side, it has a fairly low insulation value (R) per inch ranging between 2.9 and 3.8 and is easily compressed which further reduces its R value.
An older form of insulation is loose or blown in. This insulation can be cellulose (best R value of the three at 3.2 – 3.8 per inch), glass fiber or mineral fiber (wool). The most common application is in outside walls and in attics over open floor joists. Offering an excellent R value, it is a good choice in new construction and in situations where you want to add insulation to an attic. Its drawbacks include settling over time in walls and the fact that when used in attics, no other use of that space is realistic. When insulating walls in retrofits, holes are drilled into each cavity to be filled, and sealed after the insulation is blown in.
The newest player in the insulation game is foam, whether in sheet or spray form. Foam sheeting is typically used on the exterior of the home and EPA recommends it under all residing projects. It can also be used just about anywhere it can be easily attached like between wall studs or in ceilings. Sheet foam offers great R (4 per inch) values and can be removed to access utilities behind it. On the renovation front, it can be expensive to install from a labor perspective.
Spray foam insulation comes in both open and closed cell forms. Personally, I do not see the reason for the open cell version. It allows for infiltration of water, dust and mold, to name a few while closed cell does not. Spray foam is the most expensive insulation you can buy at the moment but it is also one of the best. It has very high R values (6.0 per inch for closed cell), can be applied in any area of the home and fills gaps and cracks perfectly. Anyone who has ever dabbled with Crazy Foam around the house knows what it can do. On the downside, it makes it very difficult to access any wires or pipes under the foam so is best reserved for new construction or finishing spaces. And, while the chemistry is much improved today, some people may be sensitive to the chemicals used in the foam.
Your particular situation will determine the best insulation for your home. And, when it’s all done, your energy bill will thank you.