Frequently Asked Questions
- What does R-value mean?
- How much will I save by adding insulation to the walls, ceilings, and floors of my home?
- How much insulation should my house have?
- What is the difference among fiberglass, rock and slag wool, cellulose, and foam insulation?
- What words should I watch out for in contracts or job estimates?
- What must new home sellers tell new home buyers?
- Why hire a professional insulation contractor rather than a home improvement contractor or general contractor?
- Can insulation help reduce unwanted sound?
- What should I know before hiring an insulation contractor?
- Where can I get more information about insulation?
- For a “green home,” do I really need a high-efficiency furnace, high-efficiency appliances, and new windows?
1. What does R-value mean?
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. Insulation helps keep your home cool during the summer months and warm during the winter months.
2. 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 $1,500 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 probably 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.
3. How much insulation should my house have?
“Insulation,” says Bob Vila, host of the nationally syndicated TV program that bears his name, “is the most efficient energy-saving expenditure.” Vila says homeowners should check attics to determine the amount of insulation already installed. “Most homes built before 1980 have inadequate insulation,” he said, noting that if insulation between the joists of the attic floor comes only to the top of the joist, it probably makes sense to install more insulation.
The U.S. Department of Energy recommends home insulation R-values based on where you live. See R-value recommendations or use the R-value calculator.
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.
4. What is the difference among fiberglass, rock and slag wool, cellulose, and foam insulation?
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.
Rock and slag wool are manufactured similarly to fiberglass, but use natural rock and blast furnace slag as its raw material. Typical forms are loose-fill, blanket, or board types.
Cellulose is a 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.
5. What words should I watch out for in contracts or job estimates?
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. “14 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.
6. What must new home sellers tell new home buyers?
Every new home seller must put specific information about insulation in every home sales contract. See Federal Rule 460.16 for details. Local and state governments may have additional rules and regulations governing consumer contracts.
7. Why hire a professional insulation contractor rather than a home improvement contractor or general contractor?
ICAA-member professional insulation 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 retarders, 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.
8. 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. Visit Owens Corning’s Quiet Zone for information on controlling noise.
9. What should I know before hiring an insulation contractor?
Consider focusing your search on insulation contractors who are members of the Insulation Contractors Association of America (ICAA), the nonprofit trade association of insulation contractors and suppliers. You can find ICAA members in your area. ICAA members must subscribe to the ICAA Members Code of Ethics. Get a written estimate before agreeing to any work.
Before you hire a professional insulation contractor, take a look at Title 16, Section 460 of the Federal Trade Commission’s Code of Federal Regulations. The purpose of this regulation is to ensure that consumers are provided essential pre-purchase information about R-values. Find out what insulation contractors must tell their customers. Local or state governments may have additional rules and regulations regarding consumer contracts.
10. Where can I get more information about insulation?
- General: U.S. Department of Energy and Energy Star, a service of the U.S. Environmental Protection Agency
- Fiberglass, Rock and Slag Wool Insulation: North American Insulation Manufacturers Association (NAIMA)
- Cellulose Insulation: Cellulose Insulation Manufacturers Association (CIMA)
- Spray Foam: Spray Polyurethane Foam Alliance (SPFA)
11. For a “green home,” do I really need a high-efficiency furnace, high-efficiency appliances, and new windows?
It’s better to go low-tech according to Lane Burt, a building-energy expert with the Natural Resource Defense Council. Hire a pro to find all the leaks in your home and plug them up. This should cost much less than a new heating system, so you won’t be heating the outside of your home. The best energy efficiency measure you can take is insulating and air sealing your home, according to McKinsey & Company.
ICAA – Insulation Contractors Association of America