Frequently Asked Questions

What is HeatBloc Attic Heat Barrier?
HeatBloc is an aluminum colored, water-based, low emissivity (low-e) coating. When applied to building materials such as plywood, OSB or plasterboard, HeatBloc lowers their surface emissivity to 0.25 or lower, thereby blocking over 75% of the radiant heat trying to enter the home. It is classified by ASTM as an Interior Radiation Control Coating (IRCC).

How does HeatBloc Attic Heat Barrier work?
HeatBloc radiant heat barrier works by changing the emissivity of the surface where it is applied. Building products such as wood, brick, and plasterboard have high emissivities (0.7-0.95). When heated, they radiate most of their heat to cooler surfaces by allowing the heat to penetrate the roof into the attic and from the attic into the house. HeatBloc lowers their surface emissivity to under 0.23, lessening their ability to radiate heat and therefore letting less heat penetrate the roof into the attic.

What is a radiant heat barrier?
Heat penetrates buildings in three ways: conduction, convection and radiation. Radiation is the transfer of heat by electromagnetic waves known as thermal radiation. Thermal radiation is a form of invisible light that travels through the air from a warm to a cool surface. Warm surfaces, such as roof decks warmed by the sun, will radiate or emit their heat to cooler interior building surfaces. Radiant heat barriers address heat flows by radiation. A radiant heat barrier is a low-e surface placed in the path of thermal radiation that blocks heat transfer.

What is emissivity?
Emissivity is the ability of a surface to radiate or emit energy in the form of long wave electromagnetic radiation. It is represented by a value from 0 to 1. The closer the value is to 1, the less effective the surface is at impeding radiant heat transfer. Wood has an emissivity of 0.90. Thus, when wood is heated above the temperature of surrounding surfaces, it will tend to transfer 90% of its heat energy by radiation. HeatBloc, when applied to most non-porous surfaces, will decrease the surface emissivity to 0.25 or lower, allowing less than 25% of the heat energy to be transferred by radiation.

What is the role of airspace when using HeatBloc?
To function effectively, a radiant heat barrier must face an airspace of 1" or greater. A radiant heat barrier will not function if sandwiched between two solid surfaces. HeatBloc, when installed on the underside of roof decking, normally faces downward into the attic. If insulation is installed in the cavity formed by the roof trusses and roof decking (as in a cathedral ceiling), at least 1" should be allowed between the top of the insulation and the HeatBloc surface.

Does HeatBloc degrade over time and what is the product lifespan?
HeatBloc does not lose its effectiveness over time like some products. Foils can tear and require the staples to penetrate the barrier. Foil chips can accumulate dust, which diminishes their effectiveness. HeatBloc will last as long as the surface area it is applied to is not damaged or disturbed and nothing is coming in contact with the product.

Is HeatBloc permeable to water?
Yes! HeatBloc allows water vapor to permeate, and does not trap water vapor within roof decks or sidewalls. This is vitally important in attic conditions.

Do radiant heat barriers lower heating costs?
While they are most effective at lowering cooling costs, studies performed by the University of Kansas have showed a 15% reduction in heat loss through the attic when radiant barriers are used.

What is the coverage rate for HeatBloc?
Recommended coverage for HeatBloc is 325 - 500 square feet per gallon depending on the porosity of the substrate.

What is the recommended application method for HeatBloc?
For best results, spray application using a spray pump size ¾ GPM or greater, 2,000 psi and tip size of 0.017” to 0.021”. The product can be rolled with a 3/8” synthetic nap roller, however, roofing nails penetrating the surface can make brushing or rolling difficult.

Can HeatBloc be used on sidewalls?
Yes, but HeatBloc is normally more effective when used under roofs. Roof surfaces are generally much hotter than sidewalls. Up to 80% of the summer heat gain is from above. Lower surfaces become more effective in controlling radiant heat transfer as the temperature of the radiant heat source increases. However, in tropical climates where no insulation is used in sidewalls, HeatBloc can substantially help increase interior comfort levels.

Can HeatBloc be used in vent-skin construction?
Yes. In vent-skin roofs HeatBloc should be applied on the underside of the outer roof skin facing down into the vent channel. On vent-skin sidewalls HeatBloc should be applied on the inside of the outer skin facing into the vent channel.

Can HeatBloc be used with radiant heating systems?
Yes. It is an effective heat reflector when used behind wood stoves or on walls adjacent to ceiling mounted radiant heaters in commercial applications.

Is attic ventilation important?
Absolutely! Radiant heat barriers only control radiant heat loads. Good attic ventilation helps control convection loads. Together they raise the comfort levels and lower cooling costs. Venting to allow 2.5 air changes per hour should be specified as a minimum.

Do radiant heat barriers have an "R" value?
No. R-values apply only to solid insulation or to insulating systems that control heat flows other than radiation. In independent testing of the product at the University of Kansas, the R-value of the insulation, after applying HeatBloc-75 to the roof deck, increased by 87% to 98%.

What are the benefits of fiberglass insulation?
Fiberglass insulation is a cost-effective, energy-saving product that saves money for individuals and businesses through lower utility bills while increasing the comfort levels for all building occupants.* In addition, adequate levels of fiberglass pipe insulation for industrial processes have helped make industry more efficient and more profitable by cutting energy losses and decreasing production costs. By avoiding the added energy generation necessary to heat and cool buildings, fiberglass insulation continues to be a benefit to the environment by helping to reduce pollution emissions.
Fiberglass insulation products play a significant energy-savings role by reducing energy use in homes, office buildings, businesses and manufacturing plants. In 1996, a study was conducted jointly by the Alliance to Save Energy and Energy Conservation Management, Inc. regarding the energy and environmental benefits of insulation. While the energy savings from fiberglass insulation are significant, so are the environmental benefits. By making buildings more energy efficient, fiberglass insulation helps reduce the amount of fossil fuel combustion needed to heat and cool homes, businesses, and factories. That, in turn, decreases the amount of carbon dioxide emitted into the atmosphere.
Because carbon dioxide is one of the principal "greenhouse gases" contributing to global warming, insulation plays a significant role in protecting the environment. For example, according to the "Green and Competitive" report, insulation currently in place in residential buildings reduces the amount of carbon dioxide emissions into the atmosphere by 1.35 trillion pounds each year. Almost 300 million acres of trees would have to be planted to remove this much carbon dioxide naturally from the atmosphere.

How does fiberglass insulation compare with other insulation materials?

Thermal Performance - Installed R-value
When insulating a home, it is important to get the R-value specified by the local energy code or the Department of Energy recommendations. It's also important that the product provide long-lasting thermal performance. 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.
While R-value "per inch" is promoted by some manufacturers, the overall R-value installed is what counts. Fiberglass insulation products come in R-values ranging from R-11 to R-38 for fiberglass batts and rolls. Fiberglass insulation can be blown in an attic to nearly any R-value. More R-value alternatives provide greater flexibility in meeting code energy requirements in your area.

Lifetime Performance
In order to ensure the expected energy savings, it is important that the insulation does not deteriorate, or settle, over time. Fiberglass batts and rolls do not settle. Fiberglass loose-fill insulations may settle slightly (1-3%) resulting in virtually no impact on the thermal performance of the insulation.
In contrast, cellulose insulation not only settles to a much greater degree (approximately 20%), but also at a higher rate. If cellulose insulation is being considered, make sure the installer understands that most cellulose insulations settle in attic loose-fill applications - that's a significant loss of insulating effectiveness. In fact, the Insulation Contractors Association of America recommends that an additional 25% of thickness be added for cellulose insulation to compensate for this extreme loss of R-value.

Fire Safety
Fiberglass and cellulose perform very differently in terms of fire safety. Fiberglass insulation is naturally non-combustible because it is made from sand and recycled glass. The insulation requires no additional fire-retardant chemical treatments.
Most facings attached to fiberglass insulation are combustible and should never be left exposed. Other special flame-resistant facings may be left exposed where desired, such as on a basement or crawl space wall.

Cellulose insulation is made primarily of ground-up or shredded newspaper, which is naturally combustible. To protect against fire, cellulose insulation is heavily treated with fire retardant chemicals. Though cellulose is treated with fire retardants, it is not fire proof. This means the insulation could still burn if exposed to a heat source. Also some tests have shown that fire retardant chemicals can lose their effectiveness over time.
Tests conducted by the California Bureau of Home Furnishings and Thermal Insulation demonstrated that most cellulose samples failed the standard fire safety test only six months after installation. Smoldering and re-ignition problems present additional concerns with cellulose insulation should a fire start.

Environmental Benefits
As the environmental consciousness of Americans has been heightened, the building industry has responded. This kind of rethinking has led to a strong push to use building materials with lower environmental impact.
Fiberglass insulation manufacturers have responded to this call for conservation by using increasing amounts of recycled materials in their products. As an industry, fiberglass insulation manufacturers recycle more material by weight (glass cullet - up to 40%) than any other type of insulation used in the building and construction sector.

The environmental benefits of fiberglass insulation, however, go far beyond its recycled content when analyzed from a life-cycle perspective. A life-cycle analysis is an appraisal of the environmental impacts connected with a product through an examination of the product's environmental traits during many stages including pre-manufacturing, manufacturing, distribution/packaging, use, reuse, maintenance and waste management. In reviewing each of these stages, a life-cycle evaluation of fiberglass clearly shows its environmentally beneficial attributes. As an example, consider fiberglass versus cellulose insulation.

Cellulose manufacturers claim environmental benefits, even though they may be removing newsprint from an existing recycling loop. More trees must be cut and more energy used to make new newsprint and cardboard to make up for what has been used for cellulose insulation. And when it comes to insulating the same size home, pound for pound, it takes up to three times more cellulose than fiberglass to achieve the same insulating efficiency. Both insulations use the same amount of virgin material but the virgin material in fiberglass is sand which is classified by the U.S. Environmental Protection Agency as a "rapidly renewable resource."

Is fiberglass insulation safe to use?
Yes. Fiberglass may cause itchiness and temporary skin irritation in many people handling the products. With respect to more serious effects, fiberglass insulation is one of the most thoroughly tested building materials in use today. Nearly 70 years of extensive research and comprehensive reviews by independent research organizations have concluded that there is no convincing evidence that exposure to fiberglass is associated with respiratory disease or cancer in people. Other insulation materials do not enjoy the same long history of testing as fiberglass insulation.

Is it safe to live in a home insulated with fiberglass?
Yes.

Does fiberglass cause cancer in people?
No. The International Agency for Cancer Research recently removed fiberglass from its list of possible carcinogens, based on its review of more than 15 years of research. Research conducted over the past 70 years shows that exposure levels are low, and that, even if inhaled into the lung, most fibers disappear quickly with no adverse health effects.

Is fiberglass like asbestos?
Fiberglass is fundamentally different from asbestos, both in its physical and chemical properties. Fiberglass is a man-made material. In contrast, asbestos is a naturally occurring, inorganic fiber. Our bodies can remove most types of fiberglass through a variety of mechanisms (it dissolves in the lungs, for example), while asbestos is more durable and stays in the body a lifetime. Synthetic vitreous fibers [fiberglass] differ from asbestos in two ways that may provide at least partial explanations for their lower toxicity. Because most synthetic vitreous fibers are not crystalline like asbestos, they do not split longitudinally to form thinner fibers. They also generally have markedly less biopersistence in biological tissues than asbestos fibers because they can undergo dissolution and transverse breakage.