Spray Foam Insulation vs. Fiberglass Insulation: Which Is Better for Your Middle Tennessee Property?

When it comes to insulating your home or commercial building, choosing the right material makes all the difference in comfort, energy efficiency, and long-term performance. At Complete Insulation, we install both spray foam insulation and fiberglass insulation across Nashville and Middle Tennessee—but when clients ask us, “Is spray foam insulation better?” our answer usually leans toward yes.

Let’s break down the key differences to help you decide which is right for your project.

What Is Spray Foam Insulation?

Spray foam insulation is a liquid-applied material that expands on contact, filling gaps and sealing off air leaks. It comes in two types—open-cell and closed-cell—and is known for its high insulating value and airtight barrier.

So, is foam insulation better than fiberglass? In many cases, yes. Spray foam delivers superior air sealing, which means better energy savings, fewer drafts, and more consistent indoor temperatures.

What Is Fiberglass Insulation?

Fiberglass insulation is made from tiny glass fibers and is commonly available in batts or blown-in loose fill. It’s been a go-to insulation material for decades due to its affordability and ease of installation.

While fiberglass is still a popular option, many homeowners and builders are beginning to wonder, “Is spray foam better than regular insulation?” or “Is spray foam better than fiberglass?”—especially as energy costs rise and efficiency becomes a top priority.

Comparing Performance: Is Spray Foam Insulation Better?

Let’s look at a few areas where spray foam and fiberglass differ:

1. Air Sealing

Spray foam creates an air barrier, drastically reducing heat loss and air infiltration. Fiberglass does not seal air on its own and can allow drafts unless paired with additional air-sealing measures.

• Verdict: Spray foam wins for airtightness and energy efficiency.

2. R-Value (Insulating Power)

Closed-cell spray foam has one of the highest R-values per inch of any insulation—around R-6 to R-7. Fiberglass batts typically provide R-3 to R-4 per inch.

• Verdict: Spray foam offers more insulation in less space.

3. Moisture Resistance

Spray foam—especially closed-cell—acts as a moisture barrier and resists mold growth. Fiberglass can absorb moisture, which may reduce effectiveness and contribute to mold if not properly installed.

• Verdict: Spray foam is the better choice for moisture-prone areas like crawl spaces.

4. Longevity

Once installed, spray foam insulation lasts for decades with minimal degradation. Fiberglass can settle or shift over time, reducing performance.

• Verdict: Spray foam offers longer-lasting protection.

Is Spray Foam Insulation Cheaper Than Fiberglass?

This is a common question we hear: “Is spray foam insulation cheaper than fiberglass?” The simple answer is no—spray foam usually has a higher upfront cost.

However, it’s important to consider long-term value. Because spray foam significantly reduces heating and cooling costs, it often pays for itself over time through lower utility bills. Plus, its durability means you won’t need to replace or re-fluff it down the line.

• Verdict: Fiberglass is more affordable up front, but spray foam is more cost-effective in the long run.

So, Is Spray Insulation Better?

When it comes to overall performance, energy efficiency, and long-term value, spray foam insulation is often the better choice—especially for homeowners and builders in the Middle Tennessee climate. That said, fiberglass still has a place, particularly for budget-conscious projects or when space allows for thicker insulation.

At Complete Insulation, we install both spray foam and fiberglass insulation and are happy to help you choose the right solution based on your project’s needs, timeline, and budget.

Ready to Upgrade Your Insulation?

If you’re wondering “Is spray foam insulation good?” or “Is foam insulation better than fiberglass?”—we’re here to guide you. Contact Complete Insulation today to schedule your free estimate and find the right insulation solution for your Nashville-area home or building. Whether you choose spray foam or fiberglass, you’ll get expert installation from a licensed, insured, and highly experienced team.