Superior Air Sealing – One of the biggest benefits of spray foam is that it seals all the nooks, crannies, gaps, and cracks that allow airflow in and out of your home. This improves energy efficiency, reduces pollen/dust, and creates a quieter indoor environment. Fiberglass insulation can leave gaps which compromise insulation performance.

Higher R-value – Spray foam has a high R-value (insulating value) of around R-6 per inch. This means it provides excellent thermal resistance and helps keep indoor temperatures comfortable. In comparison, fiberglass batts have an R-value of only R-3 per inch. The higher R-value of spray foam translates into better insulation with less thickness needed.

Moisture Resistance – Spray foam is highly resistant to moisture and condensation. It won’t sag from moisture like fiberglass can over time. The closed-cell structure of spray foam prevents moisture absorption. This helps prevent mold, mildew, and wood rot.

Air Sealant – In addition to insulating, spray foam functions as an air barrier. It seals the building envelope and minimizes air leakage. Stopping air leaks makes your HVAC system more efficient as it doesn’t have to work as hard.

Long Lasting – Spray foam insulation is durable and long-lasting if installed correctly. It won’t settle or deteriorate over time like other insulation solutions. It’ll provide reliable thermal performance for the life of your home.

Improved Comfort – The combination of insulation, air sealing, and moisture resistance provides improved indoor comfort. Homes insulated with spray foam maintain more consistent temperatures and have fewer drafts or cold spots.

While spray foam insulation costs more upfront than fiberglass, it offers superior insulation performance and air sealing that can pay off over time in energy savings. If properly installed, it’s a smart investment that provides comfort and efficiency for the life of your home.

On a hot day in the summer, an attic that is not properly vented can reach temperatures of 130 degrees or more. This makes it much more difficult to cool your living spaces. Adequate ventilation can reduce the attic temperature by up to 40 degrees, reducing you cooling bills and extending the life of your air conditioner by not making it work so hard.

Something you may not have thought about is the life of your roof, especially wood and asphalt shingles. High heat in the attic will make your shingles increasingly brittle, reducing the life of your roof. Additionally, many roofing manufacturers will void your warranty if you don’t have adequate attic ventilation.

Lastly, heat from an inadequately vented attic will melt the snow on the roof. As the water reaches the gutters it refreezes causing icicles and ice dams that can damage your roof and gutters.

So, make sure your attic is properly vented with intake at the lowest part, usually the soffit, and exhaust at the peak, usually the ridge. This will ensure reduced moisture in the attic that will avoid water damage and mold, lower energy bills in the summer, a longer roof life, reduced ice issues, and compliance with your roofing manufacturer’s warranty.

• Where you want or need to install/add insulation
• The recommended R-values for areas you want to insulate.

Blanket: Batt and Roll Insulation

Blanket insulation — the most common and widely available type of insulation — comes in the form of batts or rolls. It consists of flexible fibers, most commonly fiberglass. You also can find batts and rolls made from mineral (rock and slag) wool, plastic fibers, and natural fibers, such as cotton and sheep’s wool. Learn more about these insulation materials.

Batts and rolls are available in widths suited to standard spacing of wall studs, attic trusses or rafters, and floor joists: 2 inch x 4 inch walls can hold R-13 or R-15 batts; 2 inch x 6 inch walls can use R-19 or R-21 products. Continuous rolls can be hand-cut and trimmed to fit. They are available with or without facings. Manufacturers often attach a facing (such as kraft paper, foil-kraft paper, or vinyl) to act as a vapor barrier and/or air barrier. Batts with a special flame-resistant facing are available in various widths for basement walls and other places where the insulation will be left exposed. A facing also helps facilitate fastening during installation.

Foam Board or Rigid Foam

Foam boards — rigid panels of insulation — can be used to insulate almost any part of your home, from the roof down to the foundation. They are very effective in exterior wall sheathing, interior sheathing for basement walls, and special applications such as attic hatches. They provide good thermal resistance (up to 2 times greater than most other insulating materials of the same thickness), and reduce heat conduction through structural elements, like wood and steel studs. The most common types of materials used in making foam board include polystyrene, polyisocyanurate (polyiso), and polyurethane.

Loose-Fill and Blown-In Insulation

Loose-fill insulation consists of small particles of fiber, foam, or other materials. These small particles form an insulation material that can conform to any space without disturbing structures or finishes. This ability to conform makes loose-fill insulation well suited for retrofits and locations where it would be difficult to install other types of insulation.

The most common types of materials used for loose-fill insulation include cellulose, fiberglass, and mineral (rock or slag) wool. All of these materials are produced using recycled waste materials. Cellulose is primarily made from recycled newsprint. Most fiberglass products contain 40% to 60% recycled glass. Mineral wool is usually produced from 75% post-industrial recycled content.

Radiant Barriers and Reflective Insulation Systems

Unlike most common insulation systems, which resist conductive and sometimes convective heat flow, radiant barriers and reflective insulation work by reflecting radiant heat. Radiant barriers are installed in homes — usually in attics — primarily to reduce summer heat gain, which helps lower cooling costs. Reflective insulation incorporates radiant barriers — typically highly reflective aluminum foils — into insulation systems that can include a variety of backings, such as kraft paper, plastic film, polyethylene bubbles, or cardboard, as well as thermal insulation materials.

Radiant heat travels in a straight line away from any surface and heats anything solid that absorbs its energy. When the sun heats a roof, it’s primarily the sun’s radiant energy that makes the roof hot. A large portion of this heat travels by conduction through the roofing materials to the attic side of the roof. The hot roof material then radiates its gained heat energy onto the cooler attic surfaces, including the air ducts and the attic floor. A radiant barrier reduces the radiant heat transfer from the underside of the roof to the other surfaces in the attic. To be effective, it must face an air space.

Radiant barriers are more effective in hot climates, especially when cooling air ducts are located in the attic. Some studies show that radiant barriers can lower cooling costs 5% to 10% when used in a warm, sunny climate. The reduced heat gain may even allow for a smaller air conditioning system. In cool climates, however, it’s usually more cost-effective to install more thermal insulation.

Rigid Fiber Board Insulation

Rigid fiber or fibrous board insulation consists of either fiberglass or mineral wool material and is primarily used for insulating air ducts in homes. It is also used when there’s a need for insulation that can withstand high temperatures. These products come in a range of thicknesses from 1 inch to 2.5 inches.

Installation in air ducts is usually done by HVAC contractors, who fabricate the insulation at their shops or at job sites. On exterior duct surfaces, they can install the insulation by impaling it on weld pins and securing with speed clips or washers. They can also use special weld pins with integral-cupped head washers. Unfaced boards can then be finished with reinforced insulating cement, canvas, or weatherproof mastic. Faced boards can be installed in the same way, and the joints between boards sealed with pressure-sensitive tape or glass fabric and mastic.

Sprayed-Foam and Foamed-In-Place Insulation

Liquid foam insulation materials can be sprayed, foamed-in-place, injected, or poured. Foam-in-place insulation can be blown into walls, on attic surfaces, or under floors to insulate and reduce air leakage. Some installations can yield a higher R-value than traditional batt insulation for the same thickness, and can fill even the smallest cavities, creating an effective air barrier. You can use the small pressurized cans of foam-in-place insulation to reduce air leakage in holes and cracks, such as window and door frames, and electrical and plumbing penetrations.

Types of Foam Insulation

Today, most foam materials use foaming agents that don’t use chlorofluorocarbons (CFCs) or hydrochlorofluorocarbons (HCFCs), which are harmful to the earth’s ozone layer.

There are two types of foam-in-place insulation: closed-cell and open-cell. Both are typically made with polyurethane. With closed-cell foam, the high-density cells are closed and filled with a gas that helps the foam expand to fill the spaces around it. Open-cell foam cells are not as dense and are filled with air, which gives the insulation a spongy texture.

The type of insulation you should choose depends on how you will use it and on your budget. While closed-cell foam has a greater R-value and provides stronger resistance against moisture and air leakage, the material is also much denser and is more expensive to install. Open-cell foam is lighter and less expensive but should not be used below ground level where it could absorb water. Consult a professional insulation installer to decide what type of insulation is best for you.

Available foam insulation materials include:

• Cementitious
• Phenolic
• Polyisocyanurate (polyiso)
• Polyurethane.

Some less common types include Icynene foam and Tripolymer foam. Icynene foam can be either sprayed or injected, which makes it the most versatile. It also has good resistance to both air and water intrusion. Tripolymer foam—a water-soluble foam—is injected into wall cavities. It has excellent resistance to fire and air intrusion.

Reposted from Energy.gov

Installing more insulation in your home increases the R-value and the resistance to heat flow. In general, increased insulation thickness will proportionally increase the R-value. However, as the installed thickness increases for loose-fill insulation, the settled density of the product increases due to compression of the insulation under its own weight. Because of this compression, loose-fill insulation R-value does not change proportionately with thickness. To determine how much insulation you need for your climate, consult a local insulation contractor.

The effectiveness of an insulation material’s resistance to heat flow also depends on how and where the insulation is installed. For example, insulation that is compressed will not provide its full rated R-value. The overall R-value of a wall or ceiling will be somewhat different from the R-value of the insulation itself because heat flows more readily through studs, joists, and other building materials, in a phenomenon known as thermal bridging. In addition, insulation that fills building cavities densely enough to reduce airflow can also reduce convective heat loss.

Unlike traditional insulation materials, radiant barriers are highly reflective materials that re-emit radiant heat rather than absorbing it, reducing cooling loads. As such, a radiant barrier has no inherent R-value.

Although it is possible to calculate an R-value for a specific radiant barrier or reflective insulation installation, the effectiveness of these systems lies in their ability to reduce heat gain by reflecting heat away from the living space.

The amount of insulation or R-value you’ll need depends on your climate, type of heating and cooling system, and the part of the house you plan to insulate. To learn more, see our information on adding insulation to an existing house or insulating a new house. Also, remember that air sealing and moisture control are important to home energy efficiency, health, and comfort.

All of Alaska in Zone 7 except for the following Boroughs in Zone 8:

• Bethel
• Dellingham
• Fairbanks N. Star
• Nome
• North Slope
• Northwest Arctic
• Southeast Fairbanks
• Wade Hampton
• Yukon-Koyukuk

Zone 1 includes Hawaii, Guam, Puerto Rico, and the Virgin Islands.

Wall Insulation:

Whenever exterior siding is removed on an uninsulated wood-frame wall:

• Drill holes in the sheathing and blow insulation into the empty wall cavity before installing the new siding, and
• Zones 3-4: Add R5 insulative wall sheathing beneath the new siding
• Zones 5-8: Add R5 to R6 insulative wall sheathing beneath the new siding.

Whenever exterior siding is removed on an insulated wood-frame wall:

• For Zones 4 to 8: Add R5 insulative sheathing before installing the new siding.

* These recommendations are cost-effective levels of insulation based on the best available information on local fuel and materials costs and weather conditions. Consequently, the levels may differ from current local
building codes.

Source: ENERGY STAR

To understand how insulation works it helps to understand heat flow, which involves three basic mechanisms — conduction, convection, and radiation. Conduction is the way heat moves through materials, such as when a spoon placed in a hot cup of coffee conducts heat through its handle to your hand. Convection is the way heat circulates through liquids and gases, and is why lighter, warmer air rises, and cooler, denser air sinks in your home. Radiant heat travels in a straight line and heats anything solid in its path that absorbs its energy.

Most common insulation materials work by slowing conductive heat flow and–to a lesser extent–convective heat flow. Radiant barriers and reflective insulation systems work by reducing radiant heat gain. To be effective, the reflective surface must face an air space.

Regardless of the mechanism, heat flows from warmer to cooler until there is no longer a temperature difference. In your home, this means that in winter, heat flows directly from all heated living spaces to adjacent unheated attics, garages, basements, and even to the outdoors. Heat flow can also move indirectly through interior ceilings, walls, and floors–wherever there is a difference in temperature. During the cooling season, heat flows from the outdoors to the interior of a house.

To maintain comfort, the heat lost in the winter must be replaced by your heating system and the heat gained in the summer must be removed by your cooling system. Properly insulating your home will decrease this heat flow by providing an effective resistance to the flow of heat.

Types of Insulation

To choose the best insulation for your home from the many types of insulation on the market, you’ll need to know where you want or need to install the insulation, and what R-value you want the installation to achieve. Other considerations may include indoor air quality impacts, life cycle costs, recycled content, embodied energy, and ease of installation, especially if you plan to do the installation yourself. Some insulation strategies require professional installation, while homeowners can easily handle others.

Insulation Materials

Insulation materials run the gamut from bulky fiber materials such as fiberglass, rock and slag wool, cellulose, and natural fibers to rigid foam boards to sleek foils. Bulky materials resist conductive and — to a lesser degree — convective heat flow in a building cavity. Rigid foam boards trap air or another gas to resist conductive heat flow. Highly reflective foils in radiant barriers and reflective insulation systems reflect radiant heat away from living spaces, making them particularly useful in cooling climates. Other less common materials such as cementitious and phenolic foams and vermiculite and perlite are also available.