Best Insulations For Attics: Performance vs. Budget

You know your attic needs more insulation, but you need to decide which product to choose. There are a lot of factors to consider as you compare attic insulation options. Do you want to install it yourself or hire a professional? Will you need to insulate the attic again, or will this round of insulation last for decades? Can the insulation product deliver significant energy savings?

South Central Services has installed spray foam insulation in hundreds of homes. 90% of the homeowners we speak with would benefit from more attic insulation. Insufficient attic insulation, in both new and existing homes, is an epidemic around Greencastle, PA. The best choice for attics is spray foam insulation, but there are other options to consider depending on factors like ease of installation, cost, and longevity.

By the end of this article, you will know:

• The benefits and drawbacks of premium attic insulation
• The benefits and drawbacks of budget attic insulation products
• Which attic insulation is best for your situation

The Best Option For Attic Insulation: Spray Foam

Spray polyurethane foam is the premium insulation product. Unlike the budget insulations which can be purchased in-store, spray foam has to be manufactured on-site through a chemical reaction.

Pros Of Spray Foam In The Attic

• Air seal
• Does not settle
• Capable of filling unique spaces
• Permanent insulation solution
• Highest-performing insulation in the residential market

Spray foam insulation can air seal. Air sealing stops heat from traveling through the air by radiation and convection.

By creating an airtight seal, spray foam lowers energy bills, improves air quality, and makes a home more comfortable. Rather than investing in a separate product to air seal and then insulating, spray foam insulation can air seal and insulate simultaneously.

Spray foam insulation, like a blown-in product, can fill unique cavities. As a solid product, spray foam does not settle or risk airborne particles. After installation, you will not need personal protective equipment (PPE) if you ever need to interact with the insulation.

Because spray foam cannot settle, it is a permanent insulation solution. There is no upkeep, and the insulation cannot be disturbed. Once installed, spray foam's efficiency will not easily be damaged.

Cons Of Spray Foam In The Attic

• Slower install time
• Higher cost
• Must be done by a professional
• Occupant evacuation

Homeowners can install other attic insulation products, but a professional contractor must install spray foam. Working with someone else makes spray foam a product with slower install times. Residents and pets must also vacate the home while their attic is sprayed.

Spray foam is one of the most expensive insulation products, so its upfront investment cost is high. However, it is also the highest-performing insulation for residential applications.

3 Budget Insulations For Attics

We have identified 3 budget insulation options: fiberglass batts, blown-in fiberglass, and blown-in cellulose.

These insulations are cheaper to install because the raw material costs are lower compared to spray foam. These insulations also don't have to be installed by a professional, allowing you to save on labor costs by installing them yourself.

While installation is cheaper, these budget insulation products are lacking in performance. One of the reasons these products struggle to perform is their inability to air seal.

Without an air seal, the only heat transfer your insulation can stop is a conductive heat transfer. You can invest in air-sealing products for your attic and install them before budget insulation. However, purchasing additional products will raise the overall cost of insulating your attic.

Let's examine the benefits and drawbacks of each budget insulation in more detail.

1. Fiberglass Batts

Fiberglass batts are made of finely woven glass and plastic particles. In batt form, fiberglass is rectangular.

Pros Of Fiberglass Batts In The Attic

• Quick install time
• Homeowners can install themselves
• Cheaper than most insulations

Fiberglass batts are a common insulating material. Fiberglass is one of the cheapest insulation materials available. Homeowners can also save money by installing fiberglass insulation themselves.

Whether you work yourself or with a professional, fiberglass batts can be installed quickly.

Cons Of Fiberglass Batts In The Attic

• Likely to create gaps
• Cannot air seal
• Low performance
• Risk of airborne particles

While fiberglass can be installed quickly by a handy homeowner, it does not offer high performance. The blanket-like nature of the fiberglass batt means it is likely to create gaps.

Fiberglass cannot air seal. An air seal in your attic will create additional energy efficiency and comfort. However, you must invest in a separate air-sealing product before installing your insulation. Purchasing an air-sealing product will increase the cost of using fiberglass batts. Air sealing will not solve problems related to insulation gaps.

There is also the risk of the fiberglass particles becoming airborne. Wear PPE like gloves, safety glasses, and a mask whenever you interact with fiberglass. Without this PPE, your skin will become itchy, and your eyes and lungs could become irritated because of. You do not want tiny glass particles lodged in your skin, eyes, or lungs.

2. Blown-In Fiberglass

Blown-in fiberglass is made of the same glass material as batts. While batts are formed into pre-shaped rectangular blocks, blown-in is a loose-fill product.

Pros Of Blown-In Fiberglass In The Attic

• Quick install time
• Homeowners can install themselves
• Capable of filling unique spaces

Like fiberglass batts, blown-in fiberglass has a quick installation time and can be installed by homeowners.

If you choose to install blown-in fiberglass, you will have to rent a blowing machine.

Unlike fiberglass batts, blown-in fiberglass can fill in unique spaces and gaps. A fiberglass batt will likely create gaps, but blown-in fiberglass can fit into crevices to prevent gapping.

Cons Of Blown-In Fiberglass In The Attic

• Potential settling
• Cannot air seal
• Second-lowest performance
• Risk of airborne particles

Blown-in fiberglass performs better than batts but is still not a high-performing insulation product. Unlike batts, blown-in fiberglass can contour to fit the space. However, blown-in fiberglass is a lightweight and fluffy product that cannot substantially increase performance. Blown-in fiberglass also settles over time, meaning more insulation must be installed later to compensate.

Like fiberglass batts, blown-in fiberglass cannot air seal. If you want to air seal your attic to prevent air leakage, you must invest in and install an air-sealing product. After installing the air seal, you could insulate with blown-in fiberglass. An air seal will increase the efficiency of your blown-in insulation product.

Blown-in fiberglass particles can become airborne, just like fiberglass batts. PPE is vital when installing blown-in fiberglass to keep your skin, eyes, and lungs safe.

3. Blown-In Cellulose

Blown-in cellulose is a recycled-material blown-in insulation option. Cellulose is generally composed of recycled newspaper, with added natural flame retardant like borate.

Pros Of Blown-In Cellulose In The Attic

• Quick install time
• Homeowners can install themselves
• Cheaper than most insulations
• Recycled material
• Capable of filling unique spaces
• Higher performance than fiberglass

Cellulose shares many of the benefits of fiberglass. Like blown-in fiberglass, cellulose can fill unique cavities and spaces. Installation time is quick and can be completed by a homeowner with a rented blower machine. Blown-in cellulose can also be installed by a professional contractor.

Blown-in cellulose is denser and provides more performance than blown-in fiberglass. Blown-in cellulose will give the most performance of budget insulations compared to the investment cost.

Cons Of Blown-In Cellulose In The Attic

• Potential settling
• Cannot air seal
• Risk of airborne particles

Like blown-in fiberglass, blown-in cellulose can settle over time. You will need to install additional cellulose after the product has settled to restore product performance.

Like the other budget insulation options, cellulose is also not an air-sealing product. For homeowners who want to air-seal their attic and to use blown-in cellulose, a separate product must be purchased and installed before the cellulose. These air-sealing products include tapes, caulking, sealants, and poly sheeting.

While fiberglass requires PPE to protect from glass particles, cellulose requires PPE due to dust. Cellulose is a dusty insulation product, and those dust particles can become airborne. Wearing a mask and eye protection can keep your eyes and lungs free of dust.

Your Attic Needs An Airtight Seal, Regardless Of Your Insulation

Air sealing prevents air infiltration. In an attic, air sealing will prevent heat from escaping through the air. In the summertime, the air seal helps prevent heat from pushing through the attic floor into the rest of the house. In the winter, the air seal keeps conditioned air from escaping into the attic and leaving the home.

Spray foam insulation is permanent, airtight, and has a high R-value. For these reasons, we recommend spray foam as the best attic insulation.

If you cannot invest in spray foam, we recommend air-sealing with another product before installing budget insulation. While investing in an air-seal may increase your project costs, it will also increase your energy savings from these budget insulations. Some air sealing products include caulking, sheeting, and tapes.

The Bottom Line About Which Insulation Is Best For Attics

The best insulation product for attics is spray foam insulation. Spray foam insulates and air seals, offering the best performance of any attic insulation product. However, spray foam insulation is an expensive investment and requires working with a professional contractor.

You may choose budget insulation for its low cost or ease of installation. In these cases, we recommend investing in a separate air-sealing product to maximize the effectiveness of your attic insulation. Any time we install a blown-in product in an attic, we air-seal the attic floor first.

Now that you know which insulation is best for attics, your next step is to:

• Learn the process to insulate an attic with spray foam
• Calculate an estimate for insulating your attic with spray foam
• Determine if you'll insulate your attic floor or ceiling