Sheet Insulation vs Fiberglass Insulation
Rigid Sheet Insulation vs. Fiberglass Insulation: Choosing the Right Home Insulation
Insulation is a significant element of building construction and energy efficiency. Two popular types of insulation are rigid sheet insulation and fiberglass insulation. Each has distinct advantages, disadvantages, and applications, which this guide will compare in detail.
Rigid Sheet Insulation
Composition and Types: Rigid sheet insulation, also known as rigid foam insulation, is made from materials like polystyrene (expanded EPS and extruded XPS), polyisocyanurate (polyiso), and polyurethane. These materials are manufactured into sheets or panels of varying thicknesses and densities.
Thermal Performance: Rigid sheet insulation is known for its high R-value per inch, which measures thermal resistance. Polyiso typically has the highest R-value, followed by XPS and then EPS. This high R-value makes rigid sheets highly effective in insulating spaces with limited thickness.
Installation: Rigid sheet insulation is relatively easy to install. The sheets can be cut using standard tools and affixed to walls, roofs, and foundations using adhesives or mechanical fasteners. However, it requires precise cutting and fitting to minimize gaps that could lead to thermal bridging.
Moisture Resistance: Rigid foam boards are inherently moisture-resistant, particularly XPS and polyiso. This makes them perfect for areas prone to moisture, such as basements and exterior walls.
Durability and Strength: Rigid sheets are durable and provide additional structural strength. They can withstand physical stress and are less likely to settle or degrade over time compared to some other home insulation types.
Cost: Rigid sheet insulation tends to be more expensive than fiberglass insulation. The cost is offset by its higher R-value and durability, but the initial investment can be a consideration for budget-conscious projects.
Fiberglass Insulation
Composition and Types: Fiberglass insulation is made from fine glass fibers woven into batts, rolls, or loose-fill. Batts and rolls are typically used in standard framing cavities, while loose-fill is blown into attics and hard-to-reach areas.
Thermal Performance: Fiberglass insulation has a lower R-value per inch compared to rigid sheet insulation, typically around R-2.9 to R-4.3 per inch. This means thicker layers are required to achieve the same thermal performance as rigid sheets.
Installation: Installing fiberglass insulation can be more labor-intensive but is easier overall. Batts and rolls need to be cut to fit around obstacles and tightly packed into framing cavities to avoid gaps and ensure optimal performance. Loose-fill installation requires specialized equipment to blow the fibers into place.
Moisture Resistance: Fiberglass insulation is not inherently moisture resistant. It can lose its insulating properties and become a potential place for mold to grow if it gets wet. To avoid this, it’s important to install a vapor barrier in areas prone to moisture.
Durability and Settling: Fiberglass insulation can settle over time, reducing its effectiveness. It is also more susceptible to physical damage during installation or from pests, which can compromise its insulating properties.
Cost: Fiberglass insulation is generally less expensive than rigid sheet insulation. This lower cost makes it an attractive option for large projects or where budget constraints are significant.
Key Takeaways
Rigid Sheet Insulation is superior in terms of thermal performance, moisture resistance, and durability. Its higher initial cost is justified by its long-term efficiency and structural benefits. It’s great for projects where space is limited and high R-values are necessary.
Fiberglass Insulation offers a cost-effective solution with easier handling and installation in certain scenarios. It is best suited for interior spaces where moisture control is manageable, and cost savings are a priority.