Insulation is a vital component in any home that seeks to be energy-efficient. Typically placed in areas where air escapes, such as between the stud cavities inside the walls and in the attic, it serves to slow and reduce heat transfer.
By sealing air leaks and adding proper insulation to the attic, crawl spaces, and basement, homeowners stand to save an average of 15 percent on heating and cooling costs—11 percent on total energy costs—estimates the U.
Still, approximately 90 percent of single-family homes in the U. Not all insulation is created equal, and various types exist for different applications. Here, we outline the details of five major options: blanket batts and rolls, spray foam insulation, blown-in insulation, foam board or rigid foam panels, and reflective or radiant barriers.
The higher the R-value, the better the insulation is at reducing energy loss. Installing this type of insulation is an inexpensive and DIY-friendly project, since the materials are designed to fit into the standard width between wall studs, attic rafters, and floor joists. Pro tip: Keep in mind that fiberglass is a lung and skin irritant, so always wear protective clothing when handling the material. Standard fiberglass blankets and batts have R-values between R High-performance medium-density and high-density fiberglass blankets and batts have R-values between R Best for: Adding insulation to existing finished areas, as well as irregularly shaped or hard-to-reach spaces.
Spray foam insulation seals leaks and gaps inside existing walls. Liquid polyurethane is sprayed into the cavity of the wall, where it then expands and hardens into a solid foam. They also conform to the shape of the cavity, filling and sealing it thoroughly.
Slow-curing liquid foams are also available. These foams are designed to flow over obstructions before expanding and curing, and they are often used for empty wall cavities in existing buildings. There are also liquid foam materials that can be poured from a container.
Installation of most types of liquid foam insulation requires special equipment and certification and should only be done by experienced installers. Following installation, an approved thermal barrier equal in fire resistance to half-inch gypsum board must cover all foam materials. Also, some building codes don't recognize sprayed foam insulation as a vapor barrier, so installation might require an additional vapor retarder. Foam insulation products and installation usually cost more than traditional batt insulation.
However, foam insulation has higher R-values and forms an air barrier, which can eliminate some of the other costs and tasks associated with weatherizing a home, such as caulking, applying housewrap and vapor barrier, and taping joints.
When building a new home, this type of insulation can also help reduce construction time and the number of specialized contractors, which saves money. Structural insulated panels SIPs are prefabricated insulated structural elements for use in building walls, ceilings, floors, and roofs.
When installed properly, SIPs also result in a more airtight dwelling, which makes a house energy efficient, quieter, and more comfortable. SIPs not only have high R-values but also high strength-to-weight ratios. A SIP typically consists of 4- to 8-inch-thick foam board insulation sandwiched between two sheets of oriented strand board OSB or other structural facing materials. Manufacturers can usually customize the exterior and interior sheathing materials to meet customer requirements.
The facing is glued to the foam core, and the panel is then either pressed or placed in a vacuum to bond the sheathing and core together. SIPs can be produced in various sizes or dimensions. Some manufacturers make panels as large as 8 by 24 feet, which require a crane to erect. The quality of SIP manufacturing is very important to the long life and performance of the product. The panels must be glued, pressed, and cured properly to ensure that they don't delaminate.
The panels also must have smooth surfaces and square edges to prevent gaps from occurring when they're connected at the job site. Before purchasing SIPs, ask manufacturers about their quality control and testing procedures and read and compare warranties carefully.
SIPs are available with different insulating materials, usually polystyrene or polyisocyanurate foam. SIPs are made in a factory and shipped to job sites. Builders then connect them together to construct a house. For an experienced builder, a SIPs home goes up much more quickly than other homes, which saves time and money without compromising quality.
These savings can help offset the usually higher cost of SIPs. Many SIP manufacturers also offer "panelized housing kits. Fire safety is a concern, but when the interior of the SIP is covered with a fire-rated material, such as gypsum board, it protects the facing and foam long enough to give building occupants a chance to escape.
As in any house, insects and rodents can be a problem. In a few cases, insects and rodents have tunneled throughout the SIPs, and some manufacturers have issued guidelines for preventing these problems, including:. Boric acid-treated insulation panels are also available. These panels deter insects, but are relatively harmless to humans and pets. Because it can be very airtight, a well-built SIP structure may require controlled fresh-air ventilation for safety, health, and performance, and to meet many building codes.
A well-designed, installed, and properly operated mechanical ventilation system can also help prevent indoor moisture problems, which is important for achieving the energy-saving benefits of a SIP structure. Installing Insulation. When hiring a professional certified installer: Obtain written cost estimates from several contractors for the R-value you need, and don't be surprised if quoted prices for a given R-value installation vary by more than a factor of two.
Ask contractors about their experience in installing the product you are considering. Types of Insulation. Type Material Where Applicable Installation Methods Advantages Blanket: batts and rolls Fiberglass Mineral rock or slag wool Plastic fibers Natural fibers Unfinished walls, including foundation walls Floors and ceilings Fitted between studs, joists, and beams.
Concrete block insulation and insulating concrete blocks Foam board, to be placed on outside of wall usually new construction or inside of wall existing homes : Some manufacturers incorporate foam beads or air into the concrete mix to increase R-values Unfinished walls, including foundation walls New construction or major renovations Walls insulating concrete blocks Require specialized skills Insulating concrete blocks are sometimes stacked without mortar dry-stacked and surface bonded.
Insulating cores increases wall R-value. Exterior applications: must be covered with weatherproof facing. High insulating value for relatively little thickness. Can block thermal short circuits when installed continuously over frames or joists. Insulating concrete forms ICFs Foam boards or foam blocks Unfinished walls, including foundation walls for new construction Installed as part of the building structure. Cores in the blocks are typically filled with concrete to create the structural component of the wall.
Insulation is literally built into the home's walls, creating high thermal resistance. Loose-fill and blown-in Cellulose Fiberglass Mineral rock or slag wool Enclosed existing wall or open new wall cavities Unfinished attic floors Other hard-to-reach places Blown into place using special equipment and, although not recommended, sometimes poured in.
Good for adding insulation to existing finished areas, irregularly shaped areas, and around obstructions.
Reflective system Foil-faced kraft paper, plastic film, polyethylene bubbles, or cardboard Unfinished walls, ceilings, and floors Foils, films, or papers fitted between wood-frame studs, joists, rafters, and beams. Suitable for framing at standard spacing. Bubble-form suitable if framing is irregular or if obstructions are present.
Most effective at preventing downward heat flow, effectiveness depends on spacing and number of foils. Rigid fibrous or fiber insulation Fiberglass Mineral rock or slag wool Ducts in unconditioned spaces Other places requiring insulation that can withstand high temperatures HVAC contractors fabricate the insulation into ducts either at their shops or at the job sites.
Can withstand high temperatures. Sprayed foam and foamed-in-place Cementitious Phenolic Polyisocyanurate Polyurethane Enclosed existing wall Open new wall cavities Unfinished attic floors Applied using small spray containers or in larger quantities as a pressure sprayed foamed-in-place product.
Structural insulated panels SIPs Foam board or liquid foam insulation core Straw core insulation Unfinished walls, ceilings, floors, and roofs for new construction Construction workers fit SIPs together to form walls and roof of a house. SIP-built houses provide superior and uniform insulation compared to more traditional construction methods; they also take less time to build. Blanket: Batt and Roll Insulation. Concrete Block Insulation. Foam Board or Rigid Foam. Insulating Concrete Forms.
Loose-Fill and Blown-In Insulation. Radiant Barriers and Reflective Insulation Systems. Rigid Fiber Board Insulation. Types of Foam Insulation. Other available foam insulation materials include: Cementitious Phenolic Polyisocyanurate polyiso Some less common types include Icynene foam and Tripolymer foam.
Structural Insulated Panels. The Department of Energy predicts that prices for natural gas and heating oil will rise again this winter compared with last—and that's after a year in which heating-oil prices rose sharply in most parts of the country.
Sure, you can dial down the thermostat and get used to wearing bulky sweaters indoors to cut costs. But if you've got an unfinished attic, giving it proper insulation is one of the simplest ways to keep a lid on your heating bill this season.
The Department of Energy estimates that a properly insulated attic can shave 10 to 50 percent off your heating bill. And it works the opposite way for warm climates; in summer, it helps stabilize your house's indoor temps to keep cooling needs in check. In a perfect world, you'd hire an energy auditor to tell you exactly how much protection you're getting from the few inches of attic insulation you may already have and to pinpoint things like air leaks that you can seal to make sure your insulation will do its job well.
But if you can't afford to shell out a few hundred bucks for this service, never fear: We've rounded up all the most important know-how about attic insulation costs, products, prep work, and installation right here. Keep reading for the details. The main factors that impact the cost are:. Note: If you have to insulate around electrical boxes or cables, then support from an electrician might be needed as part of the process too. Stop using your attic for storage.
Because the simplest and cheapest way to insulate an attic is to add material to the floor. But if the floor is covered in plywood, you can't stuff enough insulation beneath it to do the job sufficiently—not even in warm climates.
Plan to pull up the flooring and layer new insulation on top of the old. With the floor gone, you'll have to find a spot elsewhere for stashing those off-season clothes and that holiday decor. For DIY attic insulation, you've got two choices: loose fill or batt the common term for blanket insulation.
Both can be added to uninsulated attics or layered over existing material. Once you've decided which type is best for you, examine the material options and prices to home in on the right product.
Always check labels for specifics on whatever you buy. Insulation fibers are packaged in bags and blown in place to the desired depth and density using special machinery you can rent from a home center. You can pour the fill in place and spread it manually, but the process is much more labor-intensive and the results won't be nearly as good. This flexible insulation material is most often packaged in rolls that come in various thicknesses and standard widths, usually 16 inches and 24 inches, to fit between joists or studs in a house's framing.
They come with or without a paper or foil facing that acts as a vapor barrier. You add one or more layers to achieve the desired level of insulation. Grab a tape measure and a flashlight to see what kind of insulation you already have in the attic and how deep it is. Then use the numbers in the chart at right to estimate its R-value. Pull up and dispose of any material that's compressed, water stained, or moldy—it's useless.
Owners of houses built before take note: If what you see is lightweight, grainy, loose-looking insulation with shiny flecks, it could be vermiculite from a mine with asbestos deposits. Get it tested, and if necessary, call in a pro to remove and haul it away safely.
The Department of Energy recommends these minimum R-values for unfinished, unconditioned attics.
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