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What You Need To Know About Fiberglass Insulation

By on Mar 25, 2015
What You Need To Know About Fiberglass Insulation

Contrary to popular opinion, your home’s insulation affects both your bottom line and comfort level 365 days a year. While insulation is more vital come winter, it does play an imperative role in the summer. When push comes to shove, there is not a more prevalent product than fiberglass insulation.

Fiberglass insulation is affordable and very easy to handle. While we do recommend a pro when it comes to repairing or installing fiberglass insulation, when handled carefully, an experienced DIYer can complete the job themselves. These are just some of the many advantages fiberglass insulation has over the competition.

Continue reading to see all you have to know about fiberglass insulation.

Fiberglass Insulation R-Value

R-values tell you how well that material insulates your home. In scientific terms, this number indicates the product's resistance to heat flow. The higher the R-value, the greater its thermal resistance.

Insulations with a higher R-value will be denser, thicker and contain more air pockets. Likewise, they will also be more expensive. As you can imagine, fiberglass insulation has a lower R-value than most. That is why fiberglass is generally less expensive than other major insulation materials.

On the bright side, fiberglass insulation does have a higher R-value than cotton. According to our friends at HomeAdvisor, cotton insulation, generally, has an R-value of three to four per inch, while fiberglass ranges from five to seven per inch.

Location, Location, Location

There are certain areas of the home that need more insulation than others. Attics are very exposed and have less material blocking it from the outside world. As such, thicker or additional insulation is needed. On the other hand, your walls provide a layer of insulation themselves. Therefore, if you are installing new fiberglass insulation inside your walls, you won’t need as much or can use fiberglass with a lower R-value because cold, heat and wind have to bypass multiple layers. For example, a wall with 3 ½” fiberglass batting (R-value of 11) may have an overall R-value of nearly 14 with the siding, sheathing and drywall.

Additionally, your geographic location plays a key role as well. As you know, those of us in the Midwest need more insulation come winter than those out on the West Coast.

To help determine the right amount and R-value of your insulation, please see Great Day Improvements’s, LLC R-value Chart.

Attic Insulation


With insulation, the price is based on three simple factors: 

  • R-value (effectiveness)
  • Amount
  • DIY or professionally installed

Needless to say, more effective insulation and higher amounts of insulation bring about higher costs. Likewise, expect to spend more if you hire an insulation pro as opposed to completing the project yourself.

However, for those looking for a ballpark, according to our insulation cost estimator, the average insulation installation project costs $1,289. Fortunately, for those going with fiberglass insulation, the final price should be closer to $1,000.

DIY Safety

As I recently said, a terrific way to lower your fiberglass insulation cost is by installing it yourself. Just know, one must be very careful when handling fiberglass insulation. While the material is simple to use, it can irritate the body, so be sure to wear gloves, long-sleeves, pants, a hat and goggles. If improperly handled, fiberglass insulation installation can cause skin irritation and possibly, serious respiratory issues.

Fiberglass insulation can be purchased as batts or loose fill. Batts are generally easier to install, as they are essentially blankets of insulation that have been woven together and include a paper or foil moisture barrier.

When installing, never force fiberglass insulation into an area that is too small. If it becomes too compressed, the R-value decreases (remember, it’s already low) because the air pockets collapse. So if it is too thick, invest in a different size.

Finally, be aware of your surroundings. If you are installing insulation in the attic, make sure you watch your step. Likewise, never go over the recommended amount (manufacturer). Installation of too much batt insulation in your attic could lead to problems with household ventilation.

Cotton Insulation

Types of Insulation

To really see how fiberglass compares in the industry, you have to know its competitors. Like many other home materials, there are various kinds of insulation.

Mineral Wool Insulation: Mineral wool is similar in structure to fiberglass, but more expensive and not as easy to find. It is often compared to dusty dryer lint. This type of insulation is also available in a loose fill form that can be blown into place or poured. Unfortunately, mineral wool settles over time and cakes when wet, which results in less effectiveness.

Cellulose Insulation: Cellulose insulation is made from recycled paper. It is available as a loose fill product and has been treated to resist damage from pests and moisture. However, when moisture absorption occurs, cellulose becomes compacted, heavy and is less effective. 

Cotton Insulation: Cotton insulation is made from renewable and recycled resources and presents far fewer health hazards compared to other types of insulation. Since cotton insulation is literally made of old denim, it is perfectly safe to handle, touch and install in your home without a pro.

Spray Foam Insulation: Spray foam is a polyurethane product (high R-value) that involves mixing two chemicals that are applied with a hose. While most spray foam can be installed without incident, serious problems, including unpleasant odors, difficulty breathing and health problems can affect homeowners if the job is done incorrectly.


Despite its lower R-value, fiberglass insulation remains the most popular kid on the block. Whether you are insulating your walls, rafters or any other empty gap within the home, know that fiberglass insulation is always up for the challenge.

If you are ready for an upgrade in insulation, click here and get connected with up to four drywall and insulation pros near you.

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