When considering spray foam insulation vs fiberglass, it’s essential to understand their unique applications and benefits. Spray foam insulation, available in closed-cell and open-cell spray foam provides superior air sealing, making it ideal for areas prone to moisture or extreme weather.
On the other hand, fiberglass insulation is commonly used in fiberglass batts and insulation batts and is considered as a budget-friendly solution suitable for large, accessible spaces like attics and walls.
Each material has its strengths, spray insulation foam excels in providing a robust R-value and resistance to heat transfer, while fiberglass batts are often chosen for easy DIY installation.
According to the U.S. Department of Energy, proper insulation selection is crucial for achieving energy efficiency and reducing utility costs.
Spray Foam Insulation vs Fiberglass – A Quick Table Comparison for Right Decision
| Aspect | Spray Foam Insulation | Fiberglass Insulation |
| Types | – Open-Cell: Lightweight, breathable.- Closed-Cell: Dense, rigid, higher R-value. | – Batts: Pre-cut, easy for DIY.- Blown-In: Loose fill for irregular spaces. |
| R-Value | – Open-Cell: R-3.5 to R-4.0 per inch.- Closed-Cell: R-6.0 to R-7.0 per inch. | – Batts: R-2.9 to R-3.8 per inch.- Blown-In: R-2.2 to R-2.7 per inch. |
| Cost | – $1.50 to $3.50 per board foot (closed-cell)- Open-cell: Lower cost but less R-value. | – Batts: $0.50 to $1.50 per sq ft.- Blown-In: $0.60 to $2.30 per sq ft. |
| Performance Factors | Moisture and Mold Resistance:- Closed-cell is waterproof; open-cell absorbs moisture. | Moisture Resistance:- Resistant but can absorb moisture, potentially leading to mold. |
| Thermal Resistance:- High resistance to heat transfer, especially closed-cell. | Thermal Resistance:- Moderate; ideal for milder climates. | |
| Air Sealing:- Seals gaps and external airflow effectively, reducing energy bills. | Air Sealing:- Requires vapor barrier to prevent drafts; less effective than spray foam. | |
| Best Use Case | – Closed-Cell: Basements, crawl spaces, areas prone to extreme weather.- Open-Cell: Interior walls for sound-dampening and insulation. | – Batts: Large, accessible areas like attic and garage walls.- Blown-In: Filling wall cavities and irregular spaces. |
| Environmental Impact | – Closed-Cell: Uses chemicals with a higher environmental footprint.- Not biodegradable. | – Uses up to 30% recycled glass, reducing the environmental footprint.- Biodegradable to an extent. |
The “Why” Behind Spray Foam and Fiberglass: Understanding Their Unique Forms
Spray in Insulation
Spray foam insulation is designed to expand and seal upon application, providing an airtight barrier, so that’s why it’s called “spray foam.”
Open-cell spray foam is lightweight, allowing breathability, while closed-cell spray foam is denser, offering higher R-values and moisture resistance, making it suitable for areas prone to extreme weather. Its unique structure ensures optimal air sealing, reducing external airflow and enhancing energy efficiency.
Fiberglass Insulation:
Fiberglass insulation typically exists as batts or blown-in because its primary composition glass fibers is well-suited for these forms. The batt form ensures easy installation, especially for attic spaces, while the loose-fill or blown-in type allows for adaptability in filling irregular gaps.
This versatility makes fiberglass a popular choice for large, accessible areas where maintaining insulation thickness and budget are important considerations.
Difference Between Spray Foam and Fiberglass Insulation: Comparing Cost, R-Value and Practicality
Spray Foam Versus Fiberglass Cost
- Closed-Cell Spray Foam: Higher upfront cost but greater energy savings and moisture protection; ideal for long-term ROI.
- Open-Cell Spray Foam: More affordable option that works well for interior applications where air sealing is less critical.
- Fiberglass Batts: Cost-effective for attics and DIY projects; lower upfront cost but less efficient at long-term energy savings.
Upfront Cost
The cost of spray foam insulation vs fiberglass varies significantly based on the type of material, installation expenses, and labor requirements. Spray foam insulation, particularly closed-cell,has a higher upfront cost, ranging between $1.50 to $3.50 per board foot.
The closed cell vs open cell foam cost also differs, with open-cell spray foam being more affordable at around $0.45 to $0.65 per board foot, compared to the denser closed-cell, which offers better R-value and moisture resistance but at a higher price.
Fiberglass insulation, in contrast, is more budget-friendly, with fiberglass batts costing around $0.50 to $1.50 per square foot and blown-in fiberglass ranging from $0.60 to $2.30 per square foot.
The labor for spray foam installation is also more expensive due to the specialized equipment and expertise needed, whereas fiberglass installation is simpler, often done as a DIY project to save on labor costs.
Long-term Savings
While spray foam vs fiberglass cost may show that spray foam has a higher upfront investment, the long-term savings are substantial. Closed-cell spray foam provides superior air sealing, reducing heating and cooling costs by up to 30%, according to the U.S. Department of Energy.
This results in a faster return on investment, especially in climates with extreme temperature variations where thermal resistance is crucial. Fiberglass insulation, while cheaper to install, may require more frequent maintenance and offers less energy efficiency.
The typical payback period for fiberglass insulation can be longer since it’s more prone to air leaks and moisture infiltration, which can lead to reduced performance over time.
Performance Factors
- Closed-Cell Spray Foam: Ideal for use in areas prone to moisture, such as basements, offering both thermal resistance and moisture protection.
- Open-Cell Spray Foam: Works well for interior walls where sound-dampening is desired along with insulation.
- Fiberglass Batts: A cost-effective solution for attics but requires precise installation to avoid gaps that compromise energy efficiency.
- Blown-In Fiberglass: Better for filling irregular spaces but requires additional air sealing measures for optimal performance.
Thermal Resistance
Closed-cell spray foam offers excellent thermal resistance, with an R-value of R-6.0 to R-7.0 per inch, making it highly effective in both extreme cold and hot climates. It minimizes heat transfer, keeping homes well-insulated even in challenging weather conditions.
On the other hand, open-cell spray foam has a lower R-value per inch of around R-3.5 to R-4.0, but it’s suitable for interior spaces where maximum insulation is not needed. Fiberglass insulation, typically found in batts or blown-in forms, has an R-value per inch between R-2.9 and R-3.8.
While fiberglass is effective in mild climates, achieving the desired thermal resistance requires thicker layers compared to spray foam.
Moisture and Mold Resistance
One of the biggest advantages of closed-cell spray foam insulation is its ability to act as a vapor barrier. This makes it especially useful for areas like basements and crawl spaces, where moisture is a significant concern.
Its impermeable nature prevents mold growth and keeps moisture out, ensuring long-term durability. In contrast, fiberglass insulation can absorb moisture over time, leading to mold issues and reduced effectiveness if not properly sealed.
For this reason, fiberglass batts often need an additional vapor barrier in humid environments, especially in crawl spaces or wall cavities.
Air Sealing and Gaps
Spray foam insulation, particularly closed-cell spray foam, is known for its superior air sealing properties, effectively blocking air leaks and ensuring consistent indoor temperatures. This makes spray foam a great choice for energy-efficient homes aiming to reduce heating and cooling costs.
Fiberglass insulation, however, is not inherently air-sealing. The rigid form of fiberglass batts often leaves gaps around pipes, wires, and framing, allowing drafts to enter and reduce insulation value. Blown-in fiberglass provides slightly better coverage but still requires careful installation to reduce air gaps.
Material Composition and R-Value Comparison
- Open-cell spray foam is ideal for interior walls, offering sound-dampening capabilities along with insulation.
- Closed-cell spray foam is preferred for basements, crawl spaces, and regions with extreme weather, given its higher R-value and moisture barrier capabilities.
- Fiberglass batts are a good choice for attic spaces and walls, especially when budget constraints are important.
- For irregular spaces, blown-in fiberglass provides better coverage but needs a vapor barrier to achieve effective energy efficiency.
Material Composition
Spray foam insulation is made from polyurethane or polyisocyanurate, and has the ability to expand upon application, forming an airtight barrier. It comes in two forms: open-cell spray foam, which has a porous structure allowing some airflow, and closed-cell spray foam, which is denser and rigid, creating a moisture-resistant layer.
This unique composition allows spray foam to fill every crevice and seal against external airflow, making it highly effective for energy-efficient insulation.
On the other hand, fiberglass insulation is made from molten glass spun into fine fibers. It comes in batts and blown-in forms, making it versatile for various installation needs. Fiberglass batts are convenient for DIY projects, while blown-in fiberglass provides better coverage for irregular spaces.
Spray foam vs Fiberglass Insulation R-Value Comparison
The R-value of spray foam depends on its type: open-cell spray foam has an R-value per inch of about R-3.5 to R-4.0, while closed-cell spray foam boasts a close cell R-value of R-6.0 to R-7.0 per inch, providing superior thermal resistance. This high R-value is why closed-cell foam is often used in areas prone to extreme weather or where maximizing thermal energy retention is crucial.
On the other hand, Fiberglass insulation R-value is a bit on the lower side. The batt insulation R-value per inch is typically between R-2.9 and R-3.8, depending on the thickness and density of the material. Blown-in fiberglass has a slightly lower range, at R-2.2 to R-2.7 per inch, making it less efficient at resisting heat transfer compared to spray foam.
However, in areas where moisture resistance is not a major concern and cost is a priority, fiberglass is still an effective option.
A study by National Renewable Energy Laboratory (NREL) highlights that closed-cell spray foam is up to 50% more effective in reducing air infiltration compared to traditional fiberglass batts, primarily due to its composition and superior sealing properties.
Environmental Impact
- Closed-Cell Spray Foam: Higher environmental footprint during production but offsets with long-term energy savings.
- Fiberglass Insulation: More eco-friendly production; less effective at reducing energy use compared to spray foam.
Spray in Foam Insulation
Spray foam insulation, particularly closed-cell spray foam, has a significant environmental footprint due to the use of chemicals, including HFCs (hydrofluorocarbons), which contribute to greenhouse gas emissions.
Open-cell spray foam has a slightly lower impact but still involves petrochemical-based components that are not biodegradable. However, spray foam’s ability to improve energy efficiency by sealing gaps and reducing thermal energy loss helps in lowering overall carbon emissions, making it an eco-friendly option in terms of long-term energy savings.
According to a study by the U.S. Environmental Protection Agency (EPA), spray foam insulation can reduce a building’s energy use by up to 50% when properly installed, thereby significantly reducing its carbon footprint over time
Fiberglass Insulation
Fiberglass insulation is manufactured from recycled glass, with some products containing up to 30% recycled content. This reduces its environmental impact compared to spray foam. Fiberglass is also non-toxic, although the fibers can irritate skin and lungs if not handled properly.
The material is more biodegradable and environmentally friendly, especially when compared to the chemicals in spray insulation foam. However, fiberglass insulation R-value is lower, means less effective energy conservation over time, potentially leading to higher energy consumption.
Frequently Asked Questions (FAQs)
What is the spray foam R-value per inch?
The R-value per inch for spray foam insulation ranges from R-3.5 to R-4.0 for open-cell, and R-6.0 to R-7.0 for closed-cell, depending on the product and density.
What is the open cell spray foam R-value?
Open-cell spray foam has an R-value of around R-3.5 to R-4.0 per inch, making it suitable for interior applications like walls and ceilings.
Is foam insulation better than fiberglass?
Foam insulation, particularly closed-cell spray foam, provides better air sealing, moisture resistance, and thermal resistance than fiberglass, making it more energy-efficient but also more expensive.
How does spray foam insulation compare to fiberglass in moisture-prone areas?
Spray foam, especially closed-cell, offers superior moisture resistance, preventing mold growth, while fiberglass may absorb moisture, requiring a vapor barrier.
IIs open cell spray foam suitable for attic insulation?
Open-cell spray foam can be used in attics, providing air sealing and sound-dampening, but closed-cell is often preferred for greater R-value and moisture resistance in extreme climates.
