Insulation is one of the most important energy saving building materials used in the home. There are many products available today for building a healthy and energy efficient home. This article focuses on traditional thermal insulation products. This type of insulation is usually defined as porous, air-filled material that fills the space between the outside walls and the interior walls of the home to prevent air exchange with the outdoors.

Building a well insulated home is one of the easiest ways to reduce heating and cooling costs, thus adding to your homes overall value. Quality insulation is best installed during the building process, as it is not as easily upgraded after the home is built. Insulation saves money and provides comfort in two important ways:

Thermal Comfort

A well-insulated house saves the owner money on heating and cooling costs. Insulation resists the flow of heat. Heat is a form of energy - it always travels from hot to cold - flowing outward in winter and inward in summer. By reducing heat flow, a properly insulated home uses less energy in winter for heating and less in the summer for cooling.

Acoustical Comfort

Insulation is an excellent sound absorber. When installed in walls and ceilings it can greatly reduce sound transmission. Sound transmission is simply noise traveling through the homes outer walls, from room to room and floor to floor; such as noise from washers/dryers, HVAC systems, television sets, and children at play.

With the advantages of quality insulation being so important to most building a new home, it is no wonder industry surveys show that most new homeowners are more inclined to spend an extra one or two thousand dollars on their home insulation. The extra costs can be amortized over the 30 year life of a home loan, and help provide protection from the uncertainty of future energy costs. Insulating your home is also an important way to help the environment by simple consuming less energy, emitting fewer pollutants into the air and conversing non-renewable natural resources.

Insulation is not just for attics and outside walls. Insulation is often installed in many areas of the home including:

Product Considerations

Here are some important things to think about when making decisions insulation.

Thermal Performance -- Installed R-Value

Insulation's effectiveness is calculated based on its R-Values, which are the measurement of the insulation's resistance to heat flow. R-Value should be clearly specified on product packaging. The higher the R-Value, the more insulation a product provides and typically the higher the cost. R-Value has less to do with the insulation's thickness and more to do with what type of material is used.

When insulating a home, it is important to get the R-Value specified by the builder or the local building code. While R-Value "per inch" is promoted by some manufacturers, the overall R-Value installed is what counts.

Long Term Performance

In order to gain the expected energy savings for years to come, it's important that your insulation does not deteriorate or settle over time. To ensure long-lasting thermal performance research how the products you are considering perform over time for the application you need.

Health & Safety

How combustible or toxic are the materials you are installing, and what measures are being taken to insure a safe home? There are many insulation products on the market today. It's important to understand the properties of each material to ensure they are installed for maximum performance and safety.

Moisture

Insulation can lose its insulating efficiency or R-Value when wet. How does your insulation material react or perform if it comes into contact with moisture? Your building plans should also address preventing condensation and controlling air exchange to insure a dry, energy efficient, and healthy home.

Air Infiltration

Air infiltration generally occurs in the areas of a home that are not insulated, such as around windows, doors, fireplaces, HVAC ductwork and perimeter joints. It can, and should, be controlled with the use of housewrap, proper caulking, and sealing of band joists, sill plates, header plates, and insulation around doors, windows, electrical outlets and other openings.

The Regional Equation

Follow the recommended types of insulation specified on your plans for each area of your home. The type of heating used in your home can often play a role in determining appropriate insulation. Also, different regions will vary greatly in recommended R-Values due to differing climate considerations. For more information on insulation recommendations for a specific area, contact the local building department or the local gas or electric utility for their recommendation.

The recommended insulation levels are based on the geographic zones shown on the map below, supply by the Department of Energy:

Basic Forms of Thermal Insulation

Blanket & Batting

Blankets in the form of batts or rolls are the most common form of insulation used today. Batting generally consist of fluffy fiberglass or rock wool in sections 15 to 23 inches wide, to fit joist and stud spaces, and 4 to 8 feet long. One side of the batt is protected by kraft paper, which serves as the backing for the insulation. Batting is moisture and fire resistant and come with or without a vapor barrier. Although batts are easy to handle and install, you'll end up with more waste pieces than with blankets. Blankets are also made of fiberglass or rock wool and are sized to fit between framing. Blankets come in continuous rolls so there is less waste.

Loose-fill

Loose-fill insulation is a blown-in product. It covers the wood and works its way into the nooks and crannies of the framing. As a result provides a more complete coverage than rolled batts between the rafters or trusses. Loose-fill can be applied to sidewalls, unfinished attic floors, and hard-to-reach places. It is made of rock wool, glass fiber, cellulose fiber, vermiculite or perlite. This type is the easiest to install in walls and floor cavities that are already finished. Blown-in loose-fill insulation includes loose fibers or fiber pellets that are blown into building cavities or attics using special pneumatic equipment. Another form includes fibers that are co-sprayed with an adhesive to make them resistant to settling. The blown-in material can provide additional resistance to air infiltration if the insulation is sufficiently dense. Cellulose insulation is made of newspapers and other pulp material mixed with an adhesive bonding agent. It is blown into the wall cavities. It is essentially a wet version of the blown-in loose-fill application. It accommodates any intrusions in the wall. It sticks and dries in place. It is a messy process, but the excess material can be reused elsewhere. Cellulose insulation is the only wood-based building material that is always treated for fire retardant, making it a safe material to used.

Foam

Foam insulation is another form that can be used to insulate finished walls, floors, and ceilings from the outside. Foam has a higher R-Value than blown-in insulation, but it's much more expensive. Rigid foam board insulation consists of boards of molded or extruded polystyrene or polyurethane. Polyurethane has a high R-Value, but, along with polystyrene, it is combustible and must be covered with a 1/2-inch drywall for fire safety.

Rigid

Rigid insulation is made from fibrous materials or plastic foams and is pressed or extruded into board-like forms and molded pipe-coverings. These provide thermal and acoustical insulation, strength with low weight, and coverage with few heat loss paths. Such boards may be faced with a reflective foil that reduces heat flow when next to an air space.

Reflective

Reflective Insulation Systems are fabricated from aluminum foils with a variety of backings such as kraft paper, plastic film, polyethylene bubbles, or cardboard. The resistance to heat flow depends on the heat flow direction, and this type of insulation is most effective in reducing downward heat flow. Reflective systems are typically located between roof rafters, floor joists, or wall studs. If a single reflective surface is used alone and faces an open space, such as an attic, it is called a radiant barrier. Radiant barrriers are sometimes used in buildings to reduce summer heat gain and winter heat loss. They are more effective in hot climates than in cool climates. All radiant barriers must have a low emittance (0.1 or less) and high reflectance (0.9 or more).

Remember the most important factor to consider when purchasing insulation is its R-Value. The R-Value of insulation indicates the level at which the material allows temperatures to escape. The higher the R-Value, the better the insulation should perform.

For R-Value Recommendations for your area provided by the US Dept of Energy:

http://www.ornl.gov/roofs%2bwalls/insulation/ins_16.html

For more information regarding insulation in the home provided by the US Dept of Energy:

http://www.ornl.gov/roofs%2bwalls/insulation/ins_15.html