Fiberglass Insulation

Fiberglass Insulation: A Look at Types, Uses and Everything In Between

Fiberglass Insulation: A Look at types, uses, and everything in between (March 1, 2018)

When it comes to the insulation industry’s workhorses, fiberglass is a very strong contender. Often referred to as ‘fiberglass wool,’ because of its many short plastic reinforced glass fibers drawn through tiny openings. To form such fine fibers, the glass must be maintained at 2,500° F during the process of drawing the fiber. Unlike cellulose, fiberglass doesn't settle and lose some of its thermal properties. It is ideal for homes and loud environments because of its superior sound and thermal insulating properties.


Fiberglass insulation is available in a few forms such as blown-in form, batts, and blankets.

Blown-in Fiberglass Insulation

Not to be mistaken for blown-in cellulose, blown in fiberglass is might lighter. In areas where cellulose insulation would be too heavy, such as over a ½” drywall ceiling on 24” centers,  fiberglass is the way to go.

Blankets (Batts and Rolls)

Fiberglass batts are the cheapest, easiest way to insulate walls. Fiberglass blanket insulation is an effective yet inexpensive method of reducing the flow of heat.


In cold environments, the insulation keeps the structure warmer without overworking the furnace. In hot environments, insulation blocks heat transfer into the structure. With a radiant barrier attached, the heat is reflected outward, away from the structure, reducing electricity needs. Fiberglass provides superior thermal insulation and acoustical insulation. The lightweight material can even be easily installed by a homeowner.


R-Value is the capacity of an insulating material’s resistance to heat flow. Basically, that means the higher the R-Value, the greater the insulating power of the material. While R-Value is something that is good to know, it’s not the revered determiner for all things insulation.

Reducing insulation to a number doesn’t tell the whole story, since heat flows in and out through radiation and convection. Heat loss through convection, or air flow, can account for nearly 40 percent of total energy loss in the home. This is an issue if you are only using R-Value to choose your insulation.

In blown-in orm, it reaches an R-value of 2.2 to 2.7 per inch. Batts and blankets have a much higher R-value, reaching between 3.0 and 4.0, depending on the specifics of the manufacturing process. Though blown-in fiberglass has a lower R-value compared to cellulose, its lighter weight allows you to insulate areas that may otherwise prove difficult or impossible. It works very well for a wide range of applications, which is why it’s such a popular option for homeowners and contractors alike.


Although its a popular option for contractors and homeowners, fiberglass insulation has its own set of benefits and problems you should consider before buying the material for your home or project.


  • Inexpensive
  • Suited standard stud and joist spacing that is relatively free from obstacles
  • Can be installed by homeowners easily


  • Small particles that come into contact with skin can lodge in pores, causing itchiness, rashes and irritation.
  • When inhaled, particles can cause coughing, nosebleeds, and other respiratory ailments.
  • Still allows for air flow, which is a major source of high energy bills
  • When it is disturbed, fiberglass insulation releases particulates into the air which may be inhaled by those installing or removing it.
  • Fiberglass can trap allergens, dust, and moisture which can lead to mold growth.


In addition to being used in homes and other buildings, fiberglass is often used in submarine and ship bulkheads, as well as a wide range of commercial and industrial applications, including lining auto body panels to reduce noise.

Phenol formaldehyde is a binder that has been used in fiberglass batts and blankets in the past that is being phased out of production due to potential cancer risks.

As you can see, fiberglass insulation provides a number of options and benefits in our world. That's why we stock high-quality fiberglass insulation products from Johns Manville and Knauf Insulation. If you're considering an insulation project and want to find the right fiberglass product for the job, please feel free to contact the experienced associates at Wallboard Supply Company today for more details. At Wallboard Supply Company, our job is keeping your job rolling forward.