The Truth About Fiberglass Blown-In Insulation: Separating Fact from Fiction

Insulation is an important way to reduce your home’s energy bills. It also improves your comfort and helps to protect your belongings from moisture damage.

When it comes to insulation, there are two main options – cellulose and fiberglass. They differ in several ways, however.

1. Fiberglass is a poor insulator.

Fiberglass Blown In Insulation is an insulator but it doesn’t do much to stop air movement. That’s why you need an effective air barrier as well, like a spray foam.

Aside from its poor insulating ability, fiberglass also tends to lose energy through radiation and convection. Heat flow from one side of a home to the other can account for about 40 percent of total energy loss, so you need a good barrier against that in your attic and other spaces.

In a typical fiberglass insulation production process, raw materials are mixed, then placed in a furnace at 1400 degrees Celsius (that’s about 2000 Fahrenheit). The molten glass is then spun into fibers while coated with a liquid binder. Once the fibers cool down, they are broken into smaller pieces that fall onto a conveyor belt.

2. Fiberglass is expensive.

If you are looking for a material that is light, stiff, abrasion resistant and damage tolerant, fiberglass is the way to go. It is one of the oldest composite materials in use and consistently delivers value for nearly every project.

Fiberglass batt insulation consists of plastic filaments fortified with recycled glass spun into fibers that slow the spread of heat, cold, sound and can reduce residential energy costs by up to 40 percent. The insulating effect is enhanced by blowing loose-fill fiberglass into attic and wall spaces.

Cellulose blown-in insulation is made from recycled newspaper, denim, and other cellulose products. A fire-retardant chemical is added to the mix and then a layer of polyethylene is added, creating a soft and crumbly batt that insulates well.

Both types of blown-in insulation offer a high level of fire protection, but cellulose is more eco-friendly and blocks air better than fiberglass. The cost for installing blown-in insulation depends on the type of insulation you choose, the labor rate and the size of your home.

3. Fiberglass is messy.

The tiniest glass fibers can make you sick and can be dislodged by a brush, so keep the mess to a minimum with gloves, long-sleeved shirts, pants, goggles, and a dust mask. It also pays to measure, cut and fluff your batts for an exact fit that’ll prevent heat loss.

Blown-in fiberglass is a great choice for finished walls and has an R-value of up to 3.7 per inch. Its high density helps it lower air leaks and improves overall comfort.

Cellulose, on the other hand, is made from recycled paper products and is a low-cost alternative to fiberglass that comes in small pieces, making it easy to install. But its flimsy nature can make it vulnerable to damage by rodents and insects, so it’s best left to the pros. Similarly, spray foam has its pros and cons. It has a higher R-value and better air sealing capabilities, but requires more effort to install. The best choice is the one that suits your home’s needs and budget.

4. Fiberglass is dangerous.

Fiberglass is a material that can cause irritation to the eyes, nose and throat. It can also lead to respiratory problems like asthma, bronchitis and other allergies.

It can also cause temporary skin irritation when the particles embed in the skin. Those who suffer from a rash after working with fiberglass should wash their hands regularly to avoid re-inhaling the dust.

The only way to avoid these health risks is to wear proper work gear and limit skin exposure. Using long-sleeve shirts and pants can help keep the fibers off your skin.

Occupational exposure to fiberglass occurs when workers are moving insulation materials or installing it. They should also wear goggles and gloves when working with the material.

Non-occupational exposure can occur in homes, schools, and offices where a building may have old or worn out duct work lined with fiberglass. When the ducts are damaged, there may be a release of fibers into the air.