Skip to main content

«  View All Posts

Is Blown-In Insulation Better Than Batts?

July 8th, 2024 | 4 min read

By Alexis Dingeldein

You’re researching insulation products and are trying to find the best bang for your buck. While blown-in and batt insulation are relatively inexpensive, which delivers better performance? Is it better to use blown-in insulation than to use batt?

South Central Services has insulated hundreds of new and existing homes around Chambersburg, Pennsylvania. While we primarily install spray foam insulation, we also install both blown-in and batts in appropriate contexts. We want our customers to walk away with effective insulation they can afford, so we are knowledgeable about many types of insulation.

By the end of this article, you will understand:

  • What limitations blown-in insulation has
  • What unique benefits blown-in insulation offers
  • Which type of insulation is best for your project

Blown-In Insulation Is Less Versatile Than Batt Insulation.

Insulation goes all over your house. You need insulation in your attic, basement, crawl space, and walls. You can even install insulation between your floors for extra soundproofing.

Blown-in insulation, in its traditional application, can only be used in attics. Blown-in insulation is installed by blowing loose-fill insulation all over the attic floor. Loose-fill insulations have more versatility when applied as dense pack insulation, but blown-in is most commonly used in attics.

A vented attic floor insulated with blown-in cellulose.

On the other hand, batt insulation is used in almost every area of the home. While we don’t recommend batt insulation for all the applications it is used for, batt is considerably more versatile than blown-in.

For example, batt insulation can be installed in interior walls for soundproofing. Loose-fill products would need to be densely packed into wall cavities, so blown-in isn’t even an option for interior walls without dense pack.

Batt insulation is also stuffed in basement ceilings, while blown-in insulation cannot be used between floors at all.

Are Dense Pack And Blown-In The Same Thing?

While dense pack and blown-in insulation start with the same bags of insulation, they have different applications. Loose-fill insulation can be blown across an attic floor or densely packed into wall cavities.

This article will only compare the blown-in application of loose-fill to batt insulation.

Blown-In Insulations Offer Better Performance Than Batt.

While blown-in insulation isn’t as versatile as batt, it delivers better performance in the attic. If given the choice between batt insulation or blown-in insulation for your attic, blown-in is a better option for two reasons.

  1. No sagging.
  2. No gaps.

Let’s examine these two issues with batt insulation that blown-in products avoid.

1. Batt Insulation Suffers From Sagging.

Over time, batt insulation will sag. This applies to any application with batt insulation: walls, roofs, or floors.

South Central Services installed blown-in cellulose insulation for this attic in Waynesboro, Pennsylvania.As gravity pulls on the batts, they compress and sometimes fall from their cavities. If your attic is encapsulated with batt insulation, that insulation will eventually sag, leaving sections uninsulated.

Blown-in insulation cannot sag. Since blown-in is an application of a loose-fill product, blown-in will not create holes or pockets that are not insulated. Blown-in insulation can settle over time, lowering the overall R-value of the application. However, there will not be any patches or holes left uninsulated entirely.

When fixing settled blown-in insulation, more insulation can be installed over time. Fixing sagging batt insulation can mean replacement or careful reinstallation of fallen batts.

2. Batt Insulation Often Has Gaps.

What if you plan on insulating the attic floor? If your batt insulation is installed in the floor, how can gravity create any sagging?

For batt insulation installed on the attic floor, there are often gaps in the insulation. Gaps with batt insulation are quite common because batts are not cut to fit the cavity in which they are installed. If you have a batt that is 16 inches wide and a cavity that is 17 inches wide, an inch of that cavity will be left uninsulated.

A visual representation of two common issues with fiberglass batt insulation: shrinking and gapping.

Gaps might seem like a small problem. If you insulate the entire floor, how much damage could a few gaps in insulation cause? Any gap in your insulation will allow heat and air to pass through easily. It’s similar to leaving your doors or windows cracked open in the summer heat. Even if the gap is small, heat and air will transfer.

By comparison, blown-in insulations do not have any problems with gaps. As a loose-fill product, blown-in can conform to unique cavities and fill any strange spaces in your attic construction. Rather than trying to cut batts to size to prevent gaps, blown-in fits in the nooks and crannies by its application.

Some Blown-In And Batt Products Are Better Than Others.

So far in this article, we have used the terms “batt” and “blown-in” very generally. There are many different types of batt insulation and blown-in insulation. The insulation material determines things like properties and price.

Most commonly, when people use these terms, they are referring to fiberglass batts and blown-in fiberglass. However, there are other types of both batt and blown-in.

Batt insulation could refer to other products, such as rockwool or cotton batts. Cotton and rockwool are much more expensive than fiberglass because their materials are more expensive. These batts also offer superior performance to fiberglass, such as R-value and vapor transfer.

Blown-in insulation can refer to fiberglass or cellulose. Fiberglass tends to be less expensive than cellulose insulation, but cellulose is superior to fiberglass in attic applications. Cellulose is a more dense material than fiberglass, which means less insulation can be installed to reach the necessary R-value for your attic.

A layer of loose fill cellulose insulation, which can be installed as a blown-in insulation in attics or as a dense pack insulation in wall cavities.

Blown-In Isn’t The Best Insulation, But It’s Better Than Batt.

If you’re wondering about the best insulation for your attic, the answer isn’t batt or blown-in. Our recommendation for superior attic insulation is spray foam. Spray foam delivers a high R-value and an airtight seal, blocking all three forms of heat transfer.

However, if spray foam in the attic is outside of your budget, then your best option is blown-in insulation.

The best applications for batt insulation are interior walls for soundproofing and exterior walls in a hybrid method. In an attic application, blown-in is superior to batt insulation. While blown-in may settle over time, fewer issues can arise from installation errors.

No matter what insulation you choose for your attic, we always recommend an airtight seal. With spray foam insulation, the air-seal is built into the insulation. When working with batt or blown-in products, you need a separate air-sealing product to help block radiant and convection heat. If you hire a professional, they can install both the air-seal and the blown-in insulation for you.

The Bottom Line About Blown-In Insulation And Batt Insulation

Which type of insulation is best depends on many factors, including budget, materials, and project type. If you’re considering updating your attic insulation, blown-in is the best option for a tight budget. Blown-in delivers better performance than batt in attic applications and has fewer potential installation errors.

A different insulation may be a better choice if you’re working in other areas of your home, such as your walls, basement, or crawl space. The best place for batt insulation is inside interior walls for soundproofing purposes. Fiberglass batt insulation can dampen sound at a low investment cost.

Now that you know when blown-in is a better choice than batt insulation, your next step is to:

Alexis Dingeldein

Alexis has been fascinated by spray foam insulation since 2018. When she isn’t thinking about insulation, Alexis is geeking out over storytelling and spreadsheets.