We often receive questions about the differences between spray foam insulation and the combination of fiberglass insulation, radiant barriers, and solar attic fans. Although both are labeled as “insulation,” they serve different purposes and offer distinct advantages. 

Spray Foam 

Spray foam insulation aims to create a complete seal around a building, preventing any air exchange by eliminating ventilation. In contrast, the fiberglass and radiant barrier combination relies on proper attic ventilation. A well-ventilated attic is essential for this method to be effective, allowing fresh air in and hot, moist air to escape. 

Read: How to Properly Maintain Your Attic 

Spray foam is ideal for new construction, as it fully insulates walls and attic spaces, creating a true barrier. In retrofit situations, however, applying spray foam only to the attic can create a partial seal, yielding results but at a higher cost. Think of it like an insulated cooler: the walls and lid both need insulation for maximum effectiveness. Retrofitting with spray foam can also pose challenges since most homes aren’t designed to eliminate all ventilation, which can trap moisture and lead to mold issues over time. 

Fiberglass and Radiant Barrier 

On the other hand, the fiberglass insulation and radiant barrier combination typically aligns with the design of most retrofitted homes. It doesn’t require extensive modifications and works best in a ventilated attic.  

Unlike spray foam, we don’t want to block airflow completely. Radiant barriers reflect about 95% of radiant heat, but still allow 5% to pass through, making effective ventilation crucial. Solar attic fans are our top choice for ensuring proper airflow, helping to keep the insulation cooler. 

How The HeatBusters can help

During a complimentary attic inspection, we thoroughly assess your attic and discuss your goals as a homeowner. Our aim is to guide you in the most cost-effective direction while determining how we can achieve the best results. The higher the return on investment, the better. We’re happy to explain our recommendations to help you reach your goals effectively.