Insulation FAQs

What is R-value?

R-value measures insulation’s resistance to heat flow. It can also be referred to as “thermal resistance.” The higher the R-value, the greater the insulating power. All materials having the same R-value, regardless of type, thickness, or weight, are equal in insulating power. The R-value of different insulating materials must be based on test methods established by the American Society of Testing and Materials (ASTM). Don’t forget that R-values are determined by material type, thickness, and installed weight per square foot, not by thickness alone.

How much will I save by adding insulation to the walls, ceilings, and floors of my home?

Insulation saves money, increases home comfort, and protects the environment by reducing energy use. According to the U.S. Department of Energy (DOE), the typical U.S. family spends close to $1,300 each year on energy bills. DOE statistics show that, typically, 44% of a homeowner’s utility bill goes for heating and cooling costs. DOE states that homeowners may be able to reduce their energy bills from 10% to 50% by taking certain steps. One of the major steps is increasing the amount of thermal insulation in their existing homes or purchasing additional insulation when buying new homes.

Unless your home was constructed with special attention to energy efficiency, adding insulation will reduce your utility bills. The amount of energy you conserve will depend on several factors: your local climate, the size, shape, and construction of your house, the living habits of your family, the type and efficiency of the heating and cooling systems, and the fuel you use. Energy conserved is money saved, and the annual savings increase when utility rates go up. Insulation upgrades also add to the value of your home.

How much insulation should my house have?

The U.S. Department of Energy recommends home insulation R-values based on where you live in the United States. These recommendations are detailed for various sections of the home including walls, ceilings, and basements.Be sure your new home complies with current building code requirements for insulation. These building codes establish minimum levels of insulation for ceilings, walls, floors, and basements for new residential construction.

What is the basic difference among fiberglass, cellulose, and foam insulations?

Fiberglass is made from molten sand or recycled glass and other inorganic materials under highly controlled conditions. Fiberglass is produced in batt, blanket, and loose-fill forms.

Cellulose is loose-fill made from paper to which flame retardants are added.

Foam insulations are available as rigid boards or foamed-in-place materials that can fill and seal blocks or building cavity spaces. Foams are also used in air sealing to fill gaps, cracks, or openings.

Reflective materials are fabricated from aluminum foils with a variety of backings such as polyethylene bubbles and plastic film. Reflective insulations retard the transfer of heat; they can be tested by the same methods as mass insulation and therefore assigned an R-value.

A Radiant Barrier is a building construction material consisting of a low emittance (normally 0.1 or less) surface (usually aluminum foil) bounded by an open air space. Radiant barriers are used for the sole purpose of limiting heat transfer by radiation.

What words or terms should I look for in contracts or receipts for insulation?

Once you have chosen an insulation contractor, make sure the contract includes the job specification, cost, method of payment, and warranty information provided by the insulation material manufacturer. Make sure that the contract lists the type of insulation to be used and where it will be used. Make sure that each type of insulation is listed by R-value.

Avoid contracts with vague language such as R-values with the terms “plus or minus” “+ or -” “average” or “nominal.”

Beware of any contract or verbal offering that quotes the job in terms of thickness only (e.g. “ 10 inches of insulation”). Remember, it is the R-value — not the thickness — that tells how well a material insulates. When buying insulation, be sure not to get sidetracked by the thickness of the material.

What must new home sellers tell new home buyers?

Every new home seller must put the following information in every home sales contract: the type, thickness, and R-value of the insulation that will be installed in each part of the house. For more details, click here.

Why hire a professional insulation contractor rather than a home improvement contractor or general contractor?

Certified Energy Professional contractors devote their time to insulation contracting services and focus on your energy conservation and comfort. Proper installation is essential for insulation to perform properly. Knowledge of vapor retardants, air infiltration, ventilation, recessed lighting, and water pipes are just a few of the areas critical to installation techniques. Professional insulation contractors have access to a wide variety of training, are familiar with local codes and regulations, and can offer guidance about the type and amount of insulation to be used.

Can insulation help reduce unwanted sound?

Yes. Insulation is an efficient way to reduce unwanted sound, and it is commonly used to provide a more comfortable and quieter interior environment. Insulation effectively reduces noise transmission through floors and through interior and exterior walls. A professional insulation contractor can help you select the proper insulation for your needs.