Fiberglass vs. Cellulose Insulation: Which Is Right for Your Building?

Choosing the right insulation material matters on the fronts of comfort, energy efficiency, and overall value. Fiberglass and cellulose are the industry standards. But which one should you choose for your walls and ceiling? Whether you're a homeowner renovating a home or a contractor advising customers on this important matter, we’ve broken down the basics here:

What Is Fiberglass Insulation?

As the name suggests, fiberglass insulation is composed of tiny glass fibers and often comes in batts, rolls, or loose-fill. One of the most common insulation types, it’s been around for decades.

Here are a few of the advantages:

Affordable and Easy to Find

Fiberglass insulation fits in most budgets and you can find it at most home improvement stores or from suppliers.

Fire-Resistant

As fiberglass is made from glass, it’s not prone to catching fire. This offers peace of mind that you can safely use it in a home or commercial building.

Easy to Install

Precut batts and rolls make installation a cinch, especially in walls and ceilings with standard stud spacing.

Moisture Resistant

Fiberglass isn’t porous, which helps it maintain its insulating properties even in moist conditions.

Cons of Fiberglass Insulation:

Lower R-Value Per Inch

Fiberglass has a slightly lower R-value per inch (a measure of thermal resistance) compared to some other insulation types. As a result, you might need more material to get the job done.

Potential for Gaps

A shoddy installation job can lead to gaps that affect efficiency and allow heat to escape.

Skin Irritation

The tiny glass fibers can irritate eyes and skin, so proper handling is important.

What Is Cellulose Insulation?

Cellulose insulation comes from recycled paper products like newspapers that’s treated with fire retardants like boric acid. It’s typically installed as loose-fill insulation.

Pros of Cellulose Insulation:

Eco-Friendly

The recycling factor means that cellulose is one of the most environmentally friendly options out there.

Higher R-Value

Cellulose has a higher R-value per inch compared to fiberglass, which translates to better thermal insulation and better use of resources.

Great for Hard-to-Reach Areas

Blown in, cellulose can easily fit into small gaps and awkward spaces, giving you more coverage.

Good Soundproofing

Cellulose naturally absorbs noise, making it a popular choice for homes and offices.

Cons of Cellulose Insulation:

Moisture Sensitivity

Though designed to resist mold, cellulose can absorb moisture. This can cost it to break down over time if not properly protected.

Settling Over Time

Cellulose has a tendency to settle, which can reduce its effectiveness unless properly installed and compacted.

Dusty Installation Process

Blowing in cellulose insulation is associated with poor air quality, which can be an issue without proper ventilation and equipment.

Where to Use Fiberglass and Cellulose Insulation

Both fiberglass and cellulose work well for walls and ceiling spaces, but their differences are still notable:

Walls

Affordable and easy to fiberglass batts work well for wall areas. However, for oddly shaped walls, cellulose may be the better bet.

Ceilings

Blown-in cellulose is a great addition to attic spaces because of its level of coverage. It also fills gaps where heat loss can be an issue. However, fiberglass batts also work if the ceiling is even.

Final Thoughts

The best insulation for your walls and ceiling will be determined by factors like cost, ease of application, or energy efficiency. We wish you luck as you tackle this project and others. Contact our expert team with questions.