Compare the Top Rated Insulation Types - 2018 Best & Most Popular Types of Insulation
There’s no getting around it: insulation is incredibly important. The right insulation setup can provide the best possible acoustic and thermal performance, and reduce your energy expenses to boot, while the wrong set up can cost you money and leave you in the cold. But it can be difficult to ensure you have the right insulation for the right area. There are multiple insulation materials and types, and each one has its advantages or disadvantages depending on the project.
How Does Insulation Work?
Typically, insulation works either by slowing the transfer of heat as it moves through the insulation material or (with reflective insulation systems) reducing radiant heat gain. Regardless of the method of insulation, it helps to keep the temperatures in your home or building at optimal levels. Proper insulation systems keep the cooled or heated air in your home from leaving through the attic, ceiling, floors, and walls and can save you money on your energy expenses.
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The measure of an insulation material’s resistance to heat flow is known as its R-value; a higher R-value means a higher resistance to heat. There are a few factors that go into determining R-value, such as the density, thickness, and type of insulation, but it can also depend on the age, moisture accumulation, and temperature of the material. Multi-layered insulation’s R-value can be calculated by adding the R-value of each layer.
The more insulation you install, the more the overall R-value in your home increases. Typically, increasing the thickness of your insulation will increase the R-value, with the exception being loose-fill insulation, since the settled density of this particular type of insulation increases from the compression of its own weight. But the effectiveness of this R-value is also dependent on how and where the insulation is installed. It is recommended that you contact an insulation contractor to determine the amount of insulation you will need, as well as the placement and method of installation.
Types of Insulation
There is more than one type of insulation, each with its own advantages and disadvantages depending on the area and intended use. Here are the common types of insulation you will find.
- Batts/blankets and rolls: Possibly the most familiar type of insulation to DIY enthusiasts and homeowners, this insulation comes with the advantages of being affordable and easy to install while also being readily available in many hardware stores and online locations. Installation in non-standard spacings may take a little time, as the product must be cut to size, but that can be done with a utility knife.
- Blown-in and loose-fill: Loose-fill insulation is typically made from cellulose fiber, expanded perlite and vermiculite, or glass and rock wool fibers. It is the same spun materials as batts and blankets, but is either left loose or made into pellets and generally used in attics and walls. The installation method is where the difference between blown-in and just loose-fill insulation comes in. Loose-fill insulation can be poured or stuffed into place, but it can also be blown. The distinction between just pouring it in and opting for blown-in comes in the difference in application. Blown-in loose-fill insulation goes through a machine that fluffs it before moving through a hose and filling the required space. Since the effectiveness of blown-in insulation is a direct result of the installation, it is usually best to consult a professional.
- Concrete block: Usually made of foam board, this insulation is intended to be placed on the outside of a wall in new construction and the inside of a wall in existing buildings. Some concrete block insulation is made with air or beads mixed in to increase the R-values.
- Foam board or rigid foam: This insulation is typically made from various different materials such as asphalt-impregnated fiberboard, polyisocyanurate, polystyrene, and polyurethane. These rigid panels may have foil facings in order to reflect heat and are usually used in new construction as roof or wall sheathing, but can also be used to insulate around foundations or beneath interior walls. Keep in mind that this type of insulation is classified as combustible and cannot be left exposed.
- Radiant barrier and reflective: Radiant barriers and reflective insulation are most effective and most utilized in climates with higher temperatures. Radiant barriers are made from a thin sheet of aluminum (or other reflective material) typically laid over existing or other insulation in attics. It then reflects the heat absorbed through the roof and keeps the attic, and therefore the home, cooler and slows the transfer of heat. The effectiveness of reflective insulation, also made from aluminum foil or other reflective materials, depends on the way the insulation system is set up. A single flat foil sheet will not offer as much heat protection and reflection as multiple layers that can reduce heat transfer.
- Rigid fibrous or fiber: Generally made from fiberglass or mineral wool, this insulation is meant for use in places that tend to need insulation that can withstand higher temperatures. It is recommended to contact an insulation contract for rigid fiber insulation.
- Spray foam: Designed for new construction, spray foam insulation blocks air infiltration and drafts (since it seals up any possible leaks), does not shrink or settle, and provides a high R-value. It should be mixed and installed by professionals with the proper equipment.
Ventilation is incredibly important when it comes to insulating attics or ceilings, as proper ventilation prevents condensation and heat buildup, prohibits mold growth, and provides fresh air. Most building codes require some type of roof vent in order to expel cold, heat, and moisture that can be damaging to other building materials. The combination of vents along the eaves and a continuous ridge vent along the peak of the roof is the best way to get the optimal amount of ventilation. For roofs with improper venting, cap and gable vents can help to supplement, as can turbine vents, but those require annual maintenance. You should have one square foot of net vent opening for every 150 square feet of insulated ceiling.
There are several types of insulation material: cellulose, fiberglass, foam board, foils, mineral wool, and natural fibers, to name the most common. Bulkier materials resist heat conduction by slowing the transfer of heat, while rigid foam boards trap air and other gases in order to resist heat flow. Foils and other reflective materials actively reflect incoming heat. The type of insulation material you need depends on the climate of your area and the area of the building you need insulated.
Where to Use Certain Types of Insulation
Insulation should be chosen by the builder or installer based on the climate you are in and the design of your home. You can find more information about choosing the proper insulation at the U.S. Department of Energy website. That being said, here is a guide as to what type of insulation is usually applied in which areas.
- Attic: You would be hard pressed to find a building code that does not require attic insulation. It is generally done with blown-in dry cellulose insulation that is blown-in to the depth that is required to meet any specific R-values as provided by local building codes.
- Exterior walls: Insulation between the wood studs that make up the frame of exterior walls is required. Fiberglass batts are the most common type of insulation used in this area, as it is incredibly fire resistant and an all around excellent insulator.
- Foundation walls: While not always a requirement set by local building codes, it is a good idea to insulate the foundation walls of your home. Rigid fiberglass is typically used in these areas, often running from the wall sheathing to the bottom of the foundation wall to achieve the most beneficial setup.
- Slab: In a housing setup wherein the bottom of the house sits directly on the ground and has no basement, building codes may require the slab to be insulated. The standard method for doing so is to extend rigid foam board from the top of the slab to two feet below the bottom of the slab.
- Wall sheathing: Rigid foam sheathing is typically applied to add thermal resistance to exterior walls and is often used with a material (for example, plywood) that can provide extra wall strength.
Whether your home is in the planning stage or you are just doing some renovation, it is important to speak to the builder or contractor about the insulation strategy and what will work best for you.