What's wrong with the Insulation I already have?

A side-by-side view of the three 

    major types of insulation














There is a myriad of potential dangers of “common” insulation types that most consumers are completely unaware of.  The possibility of cancer, skin irritation, and lung problems are just a few of these dangers of your existing insulation.  We will go in depth on this topic in this section.

Most are insulated with fiberglass—the pink stuff. Or your home may have cellulose—recycled newsprint. Fiberglass and cellulose do reduce your central air conditioning and heating costs, but they have three big weaknesses when compared to spray foam insulation:


“Air infiltration can account for 30% or more of a home's heating and cooling costs and contribute to problems with moisture, noise, dust, and the entry of pollutants, insects and rodents. Reducing infiltration can significantly cut annual heating and cooling costs, improve building durability, and create a healthier indoor environment.”
US Department of Energy

Fiberglass and Cellulose Insulation Poses Certain Health Risks

Warnings on fiberglass insulation rolls advise you to completely protect your self from coming into any kind of contact with the fiberglass - wear safety glasses with side shields, face mask or respirator, gloves, long tight sleeves, long pants and a hat. And still, the itchy fibers manage to get in. According to the International Agency on Cancer Research and the Environmental Protection Agency, fiberglass emits a synthetic material called styrene, which is a possible carcinogen.

Cellulose is synthesized chiefly from post-consumer recycled newspapers (it comprises at least 80 percent its total volume). The additional components it may include are binders, fiberglass skin irritants, fire retardants, ammonium sulfate, sulfuric acid, borax, boric acid, and other chemicals. Cellulose insulation presents some serious health hazards; for example, it sprinkles fibers and dusts all over the living spaces, it includes some very irritating substances like borates and sulfates, and finally, it may also carry potential cancer causing agents or carcinogens.

Did you know that an improperly insulated and sealed home delivers 4500 lbs. of excess greenhouse gases into the air each year? It can also waste 20% or more of the energy used to heat and cool the home.

Fiberglass Insulation & Health Risks

Skin Irritation

Fiberglass insulation is composed of millions of tiny fibers of glass, and one simple tap on it expels thousands of these fibers into the air. Having direct contact with these fibers can irritate the skin, eyes, nose and throat. If you must handle the fiberglass during its installation, be sure to wear a long-sleeved shirt, gloves, goggles and pants. It's also highly recommended, after handling fiberglass insulation, that you avoid scratching your skin and eyes and avoid running until you've thoroughly washed.

Lung Problems

Whenever fiberglass is trimmed, cut, sanded or sawed, its tiny fibers are released into the air. If inhaled, the fibers can get lodged in your lungs, leading to the growth of scar tissue and even cancerous tumors. The inhalation of larger fibers is also associated with the triggering of certain upper-respiratory infections and stomach irritation. A respirator with a particulate filter can be installed to prevent the inhalation of fibers.


Another risk is contamination, which can result from improper installation of or long periods of exposure to fiberglass. The tiny fibers may end up in clothing, carpeting, and air and heating ducts, contaminating the environment--meaning more people becoming susceptible to exposure. When removing fiberglass insulation, first dampen it to prevent the tiny fibers from entering the air. Also, always wash yourself thoroughly, preferable using cold water, after working with fiberglass; warm water will only cause your skin pores to open up, allowing the tiny particles to get trapped and go deeper into the skin, which can lean to infections and other health risks.

The Health Risks of Cellulose Insulation

Lung Disease

Numerous small openings made by drilling on the wall are usually filled up by cellulose insulation from the exterior. Manufacturers claim that cellulose insulation is an environmentally safe product. But, scientific researches inform us that breathing shredded paper dust shed from loose-fitting cellulose insulation can cause serious respiratory problems. In addition to, cellulose insulation can emit noxious gases from the fire retardants, inks, fungicides, insecticides, and solvents used in the manufacturing process.


Toxic Fumes

Some sorts of cellular insulations, particularly those are made of formaldehyde and small fibers, are hazardous from environmental point of view. Harmful structural ingredients like glues and backing materials can increase the potential of health risks from the toxic fumes they release into the living spaces.



Itch Inducing Particles

Persons who have preexisting skin disorders and asthma are normally allergic to cellular insulation because of its itch inducing particles. These could be potentially irritating to eyes, skins, and lungs. In addition to, if the particles cast off and enter your respiratory tract, this can pose serious threats to your internal organs and weaken your cancer fighting immune system.



Some cellulose insulations are obtained as by-products during petroleum purification so they are inflammable giving off harmful gases. So, cellulose insulated residential and commercial buildings could be a source of indoor air pollution and they are meant to adversely affect the health and well-being of the tenants of such buildings.


Effects of Borates and Boric Acid

Conscious or unconscious eating of cellulose insulation could result in death because of its highly poisonous chemical additives (i.e. borates and boric acid). Deadly toxins can also get into your body though a cut or lesion on the skin. Symptoms of poisoning include severe abdominal pain and inflammation of the skin.



The New England Journal of Medicine published a review on health effects of cellulose insulation reported that "the fire retarding chemicals used to recycle cellulose insulation could be potentially carcinogenic (cancer causing)".



Building Materials and Indoor Air Quality

Asbestos was once a common insulator until the health risks became apparent. Fiberglass was the immediate substitute, but both asbestos and fiberglass are particulate minerals. Fiberglass has since proven to have equally evident, although less severe, health risks.

Perhaps the biggest objection to fiberglass batts in green building circles comes from the binders used to glue the glass fibers into a cohesive mat. These binders usually contain formaldehyde, a chemical known to cause sensitivity in certain people and classified as a human carcinogen by the IARC and as a probable human carcinogen by the EPA.

Spray foam is a non-particle based material, and contains no micro-fibers or organic dust. Spray foam is also formaldehyde, HFCF, HFA, and HFC free. One or all of these harmful chemicals are present in nearly all traditional insulation materials. This is why spray foam has been certified by EnvirodesicsTM for Maximum indoor air quality? and recognized by LEED and Green Spec as an environmentally friendly material.


Fiberglass and cellulose insulation can be a breeding ground for mold and mildew and serve as nesting material for rodents and insects.

SPF prevents air and moisture penetration, thus greatly reducing the potential for mold and mildew growth.

Fiberglass insulation, when exposed to air leakage or moisture, can be a breeding ground for mold and mildew. Studies show that even when fiberglass insulation looks clean to the naked eye, dangerous mold can still be present. Spray foam insulation prevents mold and mildew growth by providing a continuous air and moisture barrier and does not contain nutrients necessary for mold growth.


The photograph above shows fairly clean-looking fiberglass insulation in a crawl space that has been subjected to flooding. While the insulation itself did not appear to have been flooded, with no visible mold on or in this fiberglass insulation, a simple vacuum test demonstrated that the insulation was severely contaminated with Aspergillus sp. mold.


Rodents can enter a crawl space through vents and similar openings. Once in your home, they will nest in the warm fiberglass insulation, finding plenty of food and moisture in the crawl space to live on. A damp crawl space environment can also attract other pests, such as termites, carpenter ants, and wood-boring beetles.


Fiberglass and cellulose insulation do not completely seal the building envelope

“40% of energy is lost through roofs and walls insulated with fiberglass insulation...”
US Department of Energy



“The most common insulation, fiberglass, does not stop air leakage. Certain types of insulation, such as spray foam insulation, can be significantly more effective at reducing air flow as well as heat flow.”
US Department of Energy

Studies have shown that as much as 40% of a building's total energy loss is due to air infiltration. Traditional fiberglass insulation is only stapled or placed into the wall cavities. It doesn't seal the stud and wall cavities from end to end, or top to bottom. Air infiltration can pass through these gaps, making it far less efficient than SPF. SPF not only adheres to, but forms to the walls and floors to create a tight seal and insulating barrier that stops this air leakage. Because spray foam expands, it fills these cracks and crevices, such as around plumbing fixtures and ductwork.

Fiberglass insulation loses its R-value upon installation


**Studies conducted by the Department of Energy's Oak Ridge National Laboratories show that as outside temperatures get colder, the R-value of fiberglass insulation decreases. Using a full scale climate simulator, ORNL tested loose-fill fiberglass attic insulation rated at R-19 at a variety of temperatures. When outside temperatures dipped to -8˚F, the R-19 insulation performed at R-9.2. What is more surprising was that infrared imaging revealed convective currents inside the fiberglass insulation. Warm air from inside the house would rise through the insulation, lose heat by coming in contact with the cold attic temperatures, and drop back through the insulation, forming a convective loop of constant energy loss.

It is a little known fact that fiberglass insulation loses as much as 40% of its insulating capacity when outside temperatures fall below 20˚F. When this happens, R-19 fiberglass insulation performs as if it were only R-9. LEED confirms through a Canadian cold weather study that fiberglass loses half its R-value below 0˚F. When you need it the most fiberglass insulation cannot properly insulate.


Fiberglass also performs poorly in the presence of humidity within a wall cavity higher than just 30%. In winter this leads to condensation of moisture carried in by warm air through leaks through the wall. This raises humidity levels inside the building.

Once fiberglass insulation becomes damp its performance decreases dramatically. In fact, it only takes a 1.5% increase in moisture content in fiberglass to reduce its R-value by up to 50%. When moisture is trapped in a conventional wall cavity insulated with fiberglass and sealed with a vapor barrier, insulation becomes damp and loses its ability to insulate. This also promotes mold growth and leads to structural damage.


Fiberglass & cellulose insulation will sag and settle over time

Cellulose insulation (below left) tends to settle over time, leaving the area to be insulated exposed. Fiberglass insulation (below right), although it may not happen right away, will fall victim to the forces of nature and being to fall. Both results leave areas of un-insulated or under-insulated space in your home.




Cellulose and Fiberglass Insulation

Spray Foam Insulation

Cellulose insulation is recycled paper, mostly from newsprint. Fiberglass is tiny strands of glass.

Spray foams are plastics like polyurethane and may include agricultural products, like polyols refined from castor beans.

Insulating power comes primarily from air spaces between the fibers of the material.

Closed cell insulating power comes primarily from the material. Insulating power of open cell spray foam comes primarily from thousands of tiny trapped air pockets.

Insulating power is reduced when the insulation’s air spaces are compressed. Insulating power declines over time as the material settles under its own weight.

Spray foam insulation does not shrink or change shape once it has expanded and set.

Wind and air pressure force outside air through wall and ceiling cracks and openings, allowing heat, sound, moisture, dirt and allergens to be transported by outside air, through the insulation’s porous air spaces and into interior living areas.

Spray foam insulation expands when applied, filling and sealing even the tiniest cracks and openings. This virtually eliminates air movement through exterior walls.

Government tests show that air leakage through walls and ceiling is responsible for about 40 percent of annual air conditioning and heating costs. Cellulose and fiberglass do not stop air leakage.

Because air leakage is virtually eliminated, the 40 percent of air conditioning and heating costs attributable to air leakage can also be eliminated.

Performance is typically less than published R-Values because laboratory tests of insulating power do not consider heat transfer due to air movement, settling and imperfect installation fit.

Performance typically exceeds published R-Values because laboratory tests of insulating power do not consider heat transfer due to air movement, which spray foam blocks.

Dirt and moisture carried into insulation’s air pockets with outside air create breeding conditions for mold, mildew and bacteria. Outdoor and indoor air pressure differences can eventually force harmful organisms into interior living spaces.

Solid barrier means no pathways through insulation for dirt or moisture to accumulate. No conditions for mold, mildew and bacteria to grow.

Stabilized” cellulose includes water to make the paper fibers more rigid. And no, we’re not making this up. Naturally, moisture combined with inevitable particle matter from the outside air means greater potential for mold, mildew and bacteria growth.

Closed cell spray foam insulation forms a solid barrier against moisture. Open cell spray foam insulation will absorb vapor but dissipates the moisture within a short period of time.

Fiberglass batts do not fit perfectly into spaces between wall studs and ceiling joists. A two percent gap can reduce effective R-Value by as much as 23 percent.

Spray foam insulation expands to fill any space, regardless of dimensions, shape or surface irregularity.

Attic air space is not insulated because the insulation can only be placed between ceiling joists on the “floor” of the attic. Attic air temperatures can reach 150 degrees or more during the summer.

Attic air space is insulated because insulation can bond to the underside of the roof sheathing. Attic air space stays as much as 40 percent cooler during the summer.

Very hot attic air greatly reduces the efficiency of air conditioning ducts, which typically run through the attic in Florida homes.

Much cooler attic means air conditioning ducts operate much more efficiently. R-Values do not measure this effect.

Heat stored in the attic insulation’s air spaces during the day steadily flows into the ceiling and radiates into the interior living spaces below throughout the late afternoon and evening hours. Occupants experience a “clammy” feeling.

The attic is much cooler because the insulation is above the attic rather than below it. Late afternoon and evening heat radiation from the ceiling into interior living spaces is substantially reduced. Occupants feel much more comfortable.

Cellulose is heavy and can cause the ceiling drywall to sag if improperly installed. Imagine dozens of piles of old newspapers laying directly on top of your ceiling, between the framing joists.

The weight of spray foam insulation is not significant, and it does not lay on top of your ceiling in any case.

Cellulose and fiberglass insulation do not contribute to the strength of a building’s walls or roof.

Closed cell spray foam insulation can double the strength of walls. Adhesive spray foam can increase the strength of your roof by as much as 275 percent.



Related Videos

The video below will show the common mistakes made by professional Batt insulation installers. This video will also show that even when installed correctly it is impossible to create air tight seals in order to maintain high R values. This will result in higher energy cost due to air infiltration and will reduce the effectiveness of your insulation as a sound barrier.

Right Vs Wrong: Installing Batts in Exterior Walls pt 1


Right Vs Wrong: Installing Batts in Exterior Walls pt 2