Original article posted March 2023
Updated February 2025
Choosing the right attic insulation is one of the best ways to improve energy efficiency, lower utility bills, and enjoy a comfortable indoor temperature year-round.
But with so many options, how do you know which insulation is best for your home?
In this article, we’ll talk about the three most common types of attic insulation—cellulose, fiberglass, and spray foam—and compare their R-values, costs, and benefits to help you better understand the best choice for homeowners in Austin, TX (and hot and cold climates, alike).
What Is the Best Type of Attic Insulation?
When evaluating insulation, homeowners should consider R-value, installation process, benefits like safety and environmental impact, and cost-effectiveness.
With all three of these types, it’s a good idea to contact a qualified company before installing anything yourself, as each type comes with unique installation and maintenance challenges.
Let’s take a look at the three most popular types of attic insulation and how they compare.
1. Blown-In Cellulose Insulation
Also known as “loose-fill” insulation, cellulose insulation is one of the most effective and environmentally friendly options for your attic
What Is Cellulose Insulation?
Made from 85% recycled paper products, primarily newspaper, cellulose insulation is a sustainable choice that reduces landfill waste. It’s treated with borate, making it naturally fire-resistant and pest-resistant, which is a major advantage over other insulation types.
Unlike fiberglass and spray foam, cellulose is non-toxic, won’t irritate your skin or lungs, and is safe to breathe, making installation much easier for you (the homeowner) and the installer.
Manufacturing cellulose insulation is less resource-intensive than fiberglass or spray foam. It uses less energy to produce and is often made in regional factories, which reduces transportation costs.
Because it’s a loose-fill material, it easily fills gaps, cracks, and hard-to-reach areas in your attic, creating a thermal barrier that improves your home’s energy efficiency.
Another big advantage? Installation is quick, safe, and hassle-free. Unlike spray foam, cellulose doesn’t require homeowners to stay elsewhere during the installation (saving you more money by skipping a hotel stay!). With minimal protective equipment needed, professionals can blow in cellulose insulation efficiently, delivering immediate energy savings for your home.
R-Value of Cellulose Insulation
Cellulose Insulation has an R-value of approximately 3.5 per inch, higher than fiberglass batt insulation and on par with open-cell spray foam insulation, though lower than closed-cell spray foam insulation.
Pros and Cons of Cellulose Insulation
| Pros | Cons |
| âś… Affordable
âś… High R-value for better insulation âś… Fire and pest-resistant âś… Non-toxic and safe to handle âś… Great for reducing air leaks âś… Environmentally-friendly |
⚠️ Must be kept dry to prevent moisture damage
⚠️ Shorter lifespan than spray foam (20-30 years) |
2. Fiberglass Batt Insulation
When most people think of insulation, they picture fiberglass batts—the fluffy, often bright pink rolls in attics and walls.
What Is Fiberglass Insulation?
Fiberglass insulation is a cost-effective and widely available option, making it a go-to choice for homeowners looking to insulate on a budget. It’s also relatively easy to install, which is why many people tackle it as a DIY project.
Fiberglass is made through a specialized process where molten glass is spun into thin fibers and coated with a liquid binder. These fibers break into smaller pieces and cool as they fall onto a moving conveyor belt, forming the batt.
While fiberglass is an affordable and accessible option, it has some downsides. The soft, thick batts can attract rodents and pests looking for a warm place to nest. Some pests may even chew through the insulation, potentially reducing its effectiveness and leaving gaps that expose your attic to drafts and moisture. Additionally, the tiny glass fibers can irritate the skin and lungs, so safety is crucial during installation.
If you plan to install it yourself, be sure to wear protective equipment, including:
- Well-fitted eye protection
- Heavy-duty gloves
- A dust mask or respirator
- Long-sleeved shirts and pants to prevent irritation from airborne fibers
- A hat to keep fiberglass particles out of your hair
R-Value of Fiberglass Batt Insulation
Fiberglass insulation has an R-value between 2.2 and 3.2 per inch, making it one of the lowest-performing insulation types and significantly lower than both cellulose insulation and spray foam insulation.
Pros and Cons of Fiberglass Insulation
| Pros | Cons |
| âś… Affordable
âś… DIY-friendly âś… Long lifespan if undamaged (80-100 years) |
⚠️ Can attract rodents and pests
⚠️ Low R-Value, meaning lower efficiency ⚠️ Irritates skin and lungs during installation ⚠️ Not as air-sealing as cellulose or spray foam |
3. Spray Foam Insulation
Also known as foam insulation, this dense, expanding material hardens into place, creating a powerful thermal and air barrier. While highly effective, it comes with significant risks if not applied correctly.
What Is Spray Foam Insulation?
Spray foam is one of the longest-lasting types of insulation. Still, it’s also among the most expensive and requires precise installation to avoid serious issues. It’s made from polyurethane and isocyanate, which, when combined, expand and harden to create an insulating barrier.
Unlike pre-manufactured insulation materials, spray foam is created through a chemical reaction on-site, making quality control more challenging. Small errors during application can lead to major problems.
Because closed-cell spray foam acts as both an air and moisture barrier, it can provide strong insulation, but only if applied correctly. Before installation, it’s important to inspect your attic for leaks or moisture issues, as trapped moisture behind the foam can cause rotting wood and toxic mold, leading to repairs that can cost tens of thousands of dollars.
Despite these risks, spray foam is frequently used in attics, walls, and high ceilings, though building science experts generally recommend it only for old rubble-stone basements and cellars, where its moisture-blocking properties are most effective..
Installing spray foam insulation is much more complex than the other two types on this list and must be done with care. Spray foam releases toxic fumes during application, requiring installers to wear full protective equipment like hazmat suits and respirators.
Homeowners must vacate the property for at least 24 hours while the foam cures and finishes off-gassing. If applied incorrectly, spray foam can fail to cure properly, leaving lingering chemical odors, reducing insulation performance, and even leading to structural damage.
R-Value of Spray Foam Insulation
There are two types of spray foam:
- Open-cell spray foam offers an R-value of 3.5 per inch.
- Closed-cell spray foam can get up to 7 per inch, depending on the thickness and product quality.
Pros and Cons of Spray Foam Insulation
| Pros | Cons |
| âś… Very high R-value (best for maximum energy efficiency)
âś… Long lifespan (80-100 years) âś… Air-sealing properties reduce drafts |
⚠️ Expensive compared to cellulose and fiberglass
⚠️ Extremely difficult to remove ⚠️ Not environmentally friendly ⚠️ Requires professional installation and proper ventilation ⚠️ High risk of improper installation leading to moisture damage, mold, and costly repairs |
Cellulose Insulation: the Top Choice for Austin, TX Homes
For homeowners in Austin and other warm climates, cellulose insulation stands out as the top choice. It offers superior energy efficiency, cost-effectiveness, and environmental benefits compared to other insulation types.
Cellulose insulation:
- Provides better insulation to keep your home cooler in the scorching Texas summers and warmer in the winter.
- Fills gaps and crevices more effectively than fiberglass batts, reducing drafts and improving energy efficiency.
- Delivers excellent insulation performance at a fraction of the cost of spray foam.
- Is made from non-toxic, recycled materials and contains no harsh chemicals like those found in fiberglass and spray foam.
- Produced from up to 85% recycled paper, making it one of the most sustainable insulation options available.
With its balance of affordability, performance, and sustainability, cellulose insulation is an excellent choice for keeping Austin homes comfortable and energy-efficient year-round.
Get a Free Home Insulation Inspection Today!
Home Insulation ATX is a family-owned business and have been providing home improvement services in Austin, TX since 2016.
Pie de foto: Home Insulation ATX is a family-owned business and have been providing home improvement services in Austin, TX since 2016.
Alt text: Jonathan, Monica, and Al, members of Home Insulation ATX, are together in their warehouse, standing comfortably and smiling warmly at the camera.
At Home Insulation ATX, we specialize in loose-fill cellulose insulation—the best insulation for Austin’s climate.
Looking for insulation contractors in Austin, TX? We offer free home insulation inspections to qualified homeowners. Contact us today to see how we can help improve your home’s energy efficiency and save you money on energy bills.
Call us today at 737-301-8148 or visit our website to schedule your inspection!
Sources:
https://www.greenbuildingadvisor.com/article/open-cell-spray-foam-and-damp-roof-sheathing
