Spray Foam vs Fiberglass vs Cellulose

Spray Foam vs Fiberglass vs Cellulose: What’s the Difference?

Not all insulation performs the same, and choosing the right material can make a major difference in your home’s comfort and energy costs.



While fiberglass and cellulose are common due to lower upfront cost, spray foam offers a different level of performance by addressing both insulation and air leakage.

Why Spray Foam Outperforms Traditional Insulation

Spray foam stands apart because it doesn’t just insulate—it seals.

Traditional insulation slows down airflow, but spray foam stops it completely, which is where most of the efficiency comes from.

• Creates an air-tight seal
• Prevents heating and cooling from escaping
• Improves overall home performance

As described in the conversation, spray foam is like putting a lid on a cup, while other insulation types are more like placing something loosely over it—air can still escape.

How Fiberglass and Cellulose Compare

Fiberglass and cellulose are widely used because they are more affordable upfront, but they don’t deliver the same long-term efficiency.

• They slow airflow, but don’t eliminate it
• Energy savings are more limited
• Performance depends heavily on installation quality



They can still be effective in certain situations, but they don’t provide the same level of control over air movement.

Cost vs Performance: What You’re Really Paying For

The biggest difference between these insulation types comes down to upfront cost versus long-term value.

• Fiberglass / Cellulose: Lower initial cost, lower long-term savings
• Spray Foam: Higher upfront cost, significantly better efficiency



Over time, spray foam can reduce energy bills enough to offset the initial investment—especially for homeowners planning to stay in their home.

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