The Ultimate Guide to Choosing Between Spray Foam, Fiberglass, and Cellulose Insulation

When it comes to improving comfort, reducing energy bills, and controlling indoor air quality, few upgrades are as impactful as installing the right insulation. Homeowners and business owners across Nashville and Middle Tennessee often narrow their choices to spray foam, fiberglass, and cellulose insulation. But which option is truly best for your property?

This guide breaks down the pros and cons of each type—while highlighting why Complete Insulation recommends spray foam and fiberglass as the most reliable, long-lasting solutions.

Spray Foam Insulation: The Top Performer in Energy Efficiency

If you’re looking for maximum performance, spray foam insulation outshines other options. Applied as a liquid that expands into dense foam, it forms a seamless air and moisture barrier that dramatically reduces energy loss.

Why Homeowners Love Spray Foam

Homeowners frequently prefer spray foam insulation because of its:

• Superior air sealing: Blocks drafts and prevents conditioned air from escaping.
• Moisture resistance: Helps reduce mold growth and humidity problems.
• Long-term durability: Doesn’t sag, settle, or deteriorate over time.
• Sound reduction: Creates a quieter indoor environment.
• Energy savings: Because air leakage is minimized, HVAC run-time drops significantly.

Spray foam is ideal for attics, crawl spaces, walls, and hard-to-reach areas where airtight performance matters most. Though it has a higher upfront cost than other options, the long-term utility savings and durability often make it the most cost-effective choice overall.

Fiberglass Insulation: A Trusted, Affordable, and Versatile Option

Fiberglass insulation remains one of the most widely used products for residential and commercial applications. Complete Insulation installs both batt fiberglass and blown-in fiberglass, giving customers an effective option at a friendly price point.

Benefits of Fiberglass Insulation

Homeowners choose fiberglass insulation because of its:

• Cost-effective: One of the most budget-friendly insulation materials available.
• Fire-resistant: Adds an additional layer of safety to your home or business.
• Fast installation: Ideal for both new construction and insulation upgrades.
• Mold- and mildew-resistant: Moisture does not easily penetrate the fibers.
• Flexible application: Works well in attics, walls, and floor cavities.

For many homeowners, fiberglass provides dependable thermal performance without the higher investment required for spray foam. It’s a smart option for older houses needing improved comfort on a practical budget.

Cellulose Insulation: Pros, Cons, and Why It’s Not Always the Best Choice

Cellulose insulation, commonly made from recycled paper treated with fire retardants, is popular for its eco-friendly appeal. While it offers decent thermal performance, it comes with several drawbacks that make it less ideal for long-term results—especially in Middle Tennessee’s humid climate.

Pros of Cellulose

Some of the pros of cellulose include:

• Eco-friendly material
• Good coverage when blown into attic spaces
• Comparable R-values to fiberglass

Cons of Cellulose (Why We Don’t Recommend It)

Cellulose insulation has numerous drawbacks that include:

• Highly absorbent: Cellulose readily absorbs moisture, which can lead to mold, rot, and sagging insulation.
• Settles over time: As it compresses, its effectiveness decreases—meaning you lose energy efficiency.
• Dust-heavy application: Can reduce indoor air quality during installation and disturb sensitive occupants.
• Not ideal for humid regions: Tennessee’s moisture levels often cause cellulose to break down faster than other materials.
• Requires frequent maintenance: Unlike spray foam, which lasts decades, cellulose may need to be topped off or replaced more often.

Because of these limitations, Complete Insulation focuses on offering spray foam and fiberglass, both of which provide better durability, moisture resistance, and year-round performance for local homes and businesses.

How to Choose the Right Insulation for Your Property

The best insulation depends on your goals, budget, and building structure. Here’s a quick guide:

Choose Spray Foam If You Want:

• Maximum energy efficiency
• Superior air sealing
• Long-term durability
• Protection from moisture and allergens
• The best overall performance

Choose Fiberglass If You Want:

• A cost-effective upgrade
• Reliable thermal performance
• A mold- and fire-resistant material
• A fast, simple installation
• A proven insulation solution for most spaces

Avoid Cellulose If You Want:

• Long-term performance without settling
• Strong resistance to moisture
• Cleaner installation
• Minimal maintenance needs

Ready to Upgrade Your Home’s Comfort and Efficiency?

When you want insulation that performs, lasts, and helps you save money, Complete Insulation is the team to call. We offer expert installation, high-quality materials, and solutions tailored specifically for Nashville and Middle Tennessee homes and businesses.

Contact Complete Insulation today to schedule your free inspection and get a quote for spray foam or fiberglass insulation, installed by trusted local professionals who put your comfort first.