When it comes to keeping your home comfortable and energy-efficient, insulation is one of the biggest factors to consider. Homeowners often forget about it because it’s behind their walls, but insulation makes a huge difference in your home’s temperature and energy costs. However, not all insulation is created equal, and navigating the different options on the market can be difficult.
If you find yourself wondering which type of insulation is best for your home, you’re not alone. Read on to learn the differences between cellulose, fiberglass, and spray foam insulation to see which one is right for you.
What Is Insulation?
At its core, insulation is what stands between your house and the elements, keeping both heat and cold from entering your home. It works by slowing the transfer of heat between spaces. In winter, it keeps warm air inside, while in summer, it prevents hot air from infiltrating cool interiors.
Better yet, proper insulation can lead to big savings. According to ENERGY STAR, you can save an average of 15% on heating and cooling costs by adding proper insulation and sealing your home. When your money is on the line, choosing the right insulation is a big decision.
What Is R-Value?
Experts measure an insulation’s effectiveness by its R-value, which shows its resistance to heat flow. The higher the R-value, the better the insulation’s performance.
When deciding on what insulation to add to your home, you should aim for the highest R-value insulation that’s still within your budget. Most types of insulation range from R-2 to R-5 per inch of thickness, but higher R-values come at a cost.
However, R-value isn’t the only factor in determining what insulation is best, and different types of insulation offer unique benefits. Understanding these differences can help homeowners make the best choice for their home.
Fiberglass Insulation: The Traditional Choice
Fiberglass insulation has been the standard in home construction for decades. This type of insulation contains glass fibers, and it typically comes in pre-cut batts or rolls that fit between wall studs and attic joists.
Benefits of Fiberglass Insulation
Fiberglass insulation offers several advantages that have given it its long-standing popularity:
- Affordability: Fiberglass is one of the most budget-friendly insulation options available.
- Easy installation: Pre-cut batts make DIY projects easier in accessible areas like attics.
- Widespread availability: Fiberglass insulation is available at most home improvement stores.
- Fire resistance: Fiberglass is naturally non-combustible, adding an extra layer of safety to homes.
- Long lifespan: Properly installed fiberglass insulation can last for many years without degrading.
- Pest resistance: Unlike organic materials, fiberglass doesn’t attract pests like rodents or insects.
Drawbacks of Fiberglass Insulation
Despite its benefits, fiberglass insulation does have a few limitations:
- Lower R-value: With an R-value of about 3.2 per inch, it provides less insulation than some alternatives.
- Coverage issues: Fitting fiberglass batts around obstructions in irregular spaces can be challenging and leave gaps.
- Difficult for existing walls: Installing fiberglass in existing walls typically requires opening them up, making it impractical for many retrofit projects.
Cellulose Insulation: The Eco-Friendly Alternative
Cellulose insulation is a popular alternative to fiberglass that contains recycled paper products, primarily newspaper, treated with fire retardant. You can blow this insulation into attics and walls as loose-fill insulation, creating a seamless blanket of protection.
Benefits of Cellulose Insulation
Cellulose insulation offers several advantages over traditional fiberglass:
- Higher R-value: With an R-value of about 3.5 per inch, cellulose outperforms fiberglass.
- Superior coverage: Because cellulose is loose-fill, it can fill odd-shaped areas and small crevices completely.
- Eco-friendly: Cellulose contains recycled materials and is an environmentally conscious choice.
- Sound dampening: Cellulose provides better soundproofing than fiberglass.
- Reduced air leakage: Its ability to tightly fill spaces can help minimize air leaks.
- Fire resistance: Cellulose insulation offers added fire resistance since manufacturers treat it with borate.
- Durability: Cellulose insulation can maintain its effectiveness for 20 to 30 years.
Downsides of Cellulose Insulation
While cellulose has many benefits, it’s not without its drawbacks:
- Professional installation: Because cellulose insulation requires special equipment to blow the insulation in, you’ll likely need to hire a professional to install it.
- Potential moisture issues: If cellulose comes into contact with water, it can become soggy and create an environment for mold growth.
- Settling over time: Cellulose tends to settle and condense over time, reducing its effectiveness in vertical spaces like walls.
Spray Foam Insulation: The High-Performance Option
Spray polyurethane foam (SPF) insulation is a modern solution that’s gaining popularity. You can apply it as a liquid that quickly expands to fill gaps and cracks, creating an airtight seal.
Benefits of Spray Foam Insulation
Spray foam insulation offers several advantages:
- Highest R-value: Closed-cell spray foam can achieve R-values of 6.5 or higher per inch. Open-cell SPF is lower at 3.6 to 3.9 per inch.
- Air sealing properties: It expands to fill gaps, providing excellent air sealing and insulation.
- Versatility: You can apply spray foam to almost any surface, including irregular shapes and hard-to-reach areas.
- Moisture barrier: Closed-cell spray foam acts as a moisture barrier, helping to prevent water infiltration, unlike cellulose and fiberglass.
- Structural support: Closed-cell spray foam can increase the strength of walls and roofs.
- Longevity: Spray foam insulation doesn’t settle or sag over time, maintaining its effectiveness. In some cases, it can last for 80 to 100 years.
- Pest and mold resistance: It’s resistant to mold growth and doesn’t attract pests.
Drawbacks of Spray Foam Insulation
Despite its impressive performance, spray foam insulation does have some flaws:
- Cost: It’s typically the most expensive insulation option, costing at least two to three times more than fiberglass.
- Professional installation required: The application process requires specialized equipment and expertise, which comes at a price.
- Potential for over-application: If you apply too much foam insulation, it can lead to unnecessary costs and potential issues with framing.
- Chemical sensitivities: Some individuals may be sensitive to the chemicals in spray foam.
Comparing Performance and Cost
When choosing insulation, homeowners must consider both performance and cost. Here’s a quick overview of how the three types of insulation compare:
R-Value Comparison
R-value is one of the most important factors in insulation choice since it directly relates to insulation performance. Fiberglass has the lowest r-value with an average of 3.2 per inch, while cellulose isn’t far above at 3.5 per inch. Open-cell SPF is right above it at 3.6 to 3.9 per inch, while closed-cell SPF stands tall at 6.5 or higher.
Cost Comparison
Each type of insulation varies in installation method and cost. According to Angi’s cost data, fiberglass batt installation will cost around $0.30 to $1.50 per square foot. Spray polyurethane foam (SPF) insulation will cost around $1 to $2 per square foot, and cellulose insulation costs around $0.60 to $2.30 per square foot. However, costs may vary based on your specific contractor and installation method (DIY or professional).
DIY Installation
Fiberglass batts are the most DIY-friendly option. Homeowners can install them in accessible areas like attics with basic tools and safety equipment. For more on DIY installation, check out our guide on how to install fiberglass insulation in your attic.
However, both cellulose and spray foam typically require professional installation due to the specialized equipment needed. This adds to the overall cost but ensures proper application and maximum effectiveness.
The Bottom Line: Choosing the Best Insulation for Your Home
Choosing what insulation you want to use is difficult, but it doesn’t have to be complicated. Here are a few thoughts to make your decision easier:
If cost is your primary concern, fiberglass is the best choice because of its affordability. However, if you’re more focused on performance, spray foam has the highest R-value and best air-sealing properties, making it the best option.
On the other hand, if you care more about sustainability and eco-friendliness, cellulose insulation is the top choice because of its recycled materials. No matter what you value most, there’s an insulation option that’s best for you.
Before you run to the store or hire a contractor, be sure to consider your local climate, building codes, and long-term energy savings when making your decision. It’s okay to take your time—it’s a big decision. If you’re still not sure after some heavy consideration, try meeting with an insulation expert for a consultation.
