If your attic is under-insulated, you could be losing money through your roof. Fortunately, it’s an easy fix. Beefing up insulation in your attic is one of the best ways to make a big difference in energy costs. Upgrading your roof insulation keeps heat from flowing out, reduces heating and cooling costs and makes your home more comfortable. But there are more choices than ever, so what kind of insulation is best?
How Does Insulation Work?
According to the U.S. Department of Energy, attics are one of the biggest sources of air leaks and heat loss. In winter, heat rises and flows out of the roof, and in summer heat flows in from outside. When it’s easy for air to flow in and out, it’s harder and more expensive for heating and cooling systems to do their job. Insulation involves using special materials to create resistance to the flow of heat, keeping warm spaces warm and cool spaces cool. Improving insulation in your attic is one of the most effective steps you can take to prevent energy loss and save money.
Choosing Insulation: What Is R-Value?
If you’re looking at insulation materials, R-Value is a term you’ll hear a lot. It’s shorthand for thermal resistance, which describes how well the material keeps heat from flowing out. In general, the higher the R-Value, the more effective the insulation is. When you look at a product’s R-Value, you’re usually looking at thermal resistance per square inch to allow you to compare apples to apples. However, when you’re insulating your home, you want to look at total R-Value. According to the U.S. Department of Energy, the R-Value that’s right for your home depends on climate, type of heating and cooling system and the part of the house you plan to insulate (attics tend to need more). For example, DOE recommends a total R-Value of 38 to 60 for an attic in Virginia, so if you’re using typical fiberglass insulation with an R-3 rating, it would need to be a little over a foot thick to reach the recommended level.
What Types of Insulation Work Best for My Roof?
When we think about insulation, most of us think of pink fiberglass batts in the attic, and fiberglass is still the most popular option, but there are some new materials on the scene offering new choices to consumers. Here are some types of insulation for your attic and roof:
- Blanket or Roll Insulation: Fiberglass blanket insulation is still the most common insulation choice, but mineral wool is on the upswing. Fiberglass stays popular because it’s low-cost and easy to install. However, its blanket-like construction can make it prone to leaks and tricky to install around obstructions. Fiberglass tends to compress and lose R-Value as it ages, but it still offers a lot of bang for your buck when it’s installed correctly. Because it’s made with tiny bits of glass, it can also be dangerous to handle without the right equipment.
Mineral wool is an insulation material frequently used in Europe and is becoming more prevalent in the U.S. It’s made by spinning melted rock or slag recycled from steel mills into fibers that are made into sheets of insulation. Mineral wool is more rigid and easier to cut than fiberglass and tends to have a slightly higher R-Value. It’s also a little pricier than fiberglass.
- Loose-Fill Cellulose Insulation: This plant-based insulation is often made from recycled newspapers treated with fire-retardant chemicals. It’s gaining popularity for several reasons. Because it’s made from recycled paper, cellulose is considered a green building material. Cellulose material is treated with boric acid so it’s highly fire-resistant. Cellulose insulation is trickier to install than some other materials–it uses loose material that’s blown into buildings using special hoses, so it’s usually installed by an experienced contractor. The upside is that it can be densely packed than roll insulation, has a slightly higher R-Value and is less prone to leaks than fiberglass. It also tends to be a little more expensive than blanket options.
- Spray Foam Insulation is another trending material. It’s more expensive than the other options, but experts say it often brings bigger energy savings. Spray foam insulation is usually made from polyurethane. Two different chemicals are applied with a sprayer to create a foam which then expands in your space, so there’s no measuring or cutting involved. Spray foam also seals leaks in a way that more rigid materials don’t. It’s available in lower-density open-cell foams or higher-density closed-cell foams. Closed-cell spray foam has an especially high R-Value and is water-resistant so it’s most often used in roofs. Because of the chemicals involved, spray foam is installed by professionals using protective equipment including a respirator so the overall price tag for materials and installation will be higher.
- Radiant Barrier and Reflective Insulation: Reflective insulation takes a very different approach to insulation. Made from a reflective foil material, it doesn’t reduce heat conduction like traditional insulation but reflects radiant heat rather than absorbing it. Reflective insulation is used mostly in attics and is best at reducing heat gain and bringing air conditioning costs down in the summer.
There are more choices than ever when deciding on insulation material for your attic. DryHome is your roofing specialist, but we encourage you to also make sure your home is properly insulated. Making the right decision, coupled with a properly installed roof, can impact the comfort of your home and your energy bill.