Blown In Attic Insulation Pros and Cons and Average Cost

Blown In Attic Insulation

Attic insulation is key to controlling your home temperature throughout the year. Heat naturally collects in your attic, making your house cooler or hotter depending on the season.

Blown-in insulation is one of the most effective ways to insulate your attic. In this article, we’ll be discussing what blown-in attic insulation is, its pros and cons, and the different types of insulation on the market to help you properly insulate your attic.

What is Blown-In Attic Insulation?

What Is Blown In Attic Insulation?

Blown-in attic insulation refers to cellulose, fiberglass, and other insulation that’s thick, dense, and lumpy. It has a consistency similar to that of down feathers and can fit in tight areas such as walls or in between wires or ducts.

Blown-in insulation that’s used in homes is made from a variety of materials, such as recycled newspaper, cardboard, glass, and common waste.

The “blown-in” aspect refers to using a special machine to “blow” insulation into parts of your attic. You’d typically buy a larger block of insulation, insert it into the machine, and fill in any spots that need to be insulated.

Benefits of Blown-In Attic Insulation

Benefits of Blown In Attic Insulation

Blown-in attic insulation keeps warm air from escaping your home during the winter. It also prevents heat from entering your home during the summer.

There are, however, more benefits to blown-in attic insulation that homeowners should be aware of:

  • Insulation retains warm air generated by your heater in the winter while keeping heat out of your home during the summer. This means your AC and heater units will work significantly less, saving you on your energy bills
  • Certain types of insulation like fiberglass are completely fireproof
  • With a proper blower, installation is simple and quick
  • Fiberglass and cellulose insulation can also soundproof your attic
  • Blown-in insulation can reduce condensation by controlling your attic temperature
  • Blown-in insulation gets into tighter nooks and crannies within your attic

Blown-In Attic Insulation Pros and Cons

Blown In Attic Insulation - Pros and Cons

While there are clear benefits to using blown-in attic insulation for homeowners, there are key advantages and disadvantages that are important to consider.

Let’s explore some of the pros and cons of blown-in attic insulation here:


  • Blown-in attic insulation can be inserted in areas that are too narrow or small for rolled-up batt insulation. It can fill the space between heaters and AC units in your attic to keep them properly insulated and make the best use of your attic’s space.
  • Purchasing insulation used for blown-in purposes is relatively inexpensive but doesn’t compromise the R-value, or the insulation’s resistance to conductive heat flow.
  • Insulation is often treated with borates that prevent insects and vermin from populating your attic.
  • Blown-in attic insulation can also easily be layered on top of existing insulation or to bolster already insulated areas.


  • Unless you’re an experienced contractor, installing blown-in insulation can be messy and often requires you to call up a professional.
  • If you put too much insulation in one area, it can cause the ceiling to sag.
  • You’ll need to thoroughly air seal and install soffit venting if needed.
  • If you’re blowing cellulose over existing fiberglass, you may need to cut and refit poorly laid batts and insulate plumbing first.
  • Blown-in insulation can succumb to mold and rot if it comes in contact with a lot of moisture over an extended period of —which is why it’s important to ensure the area is sealed before blowing.

Types of Blown-In Attic Insulation

Types of Blown in Attic Insulation

Now that we know the advantages and disadvantages of blown-in attic insulation, let’s take a look at the two types of insulation that homeowners typically use to insulate their attic – cellulose and fiberglass:

Cellulose insulation

Cellulose insulation is made out of recycled paper and is an economically-friendly option for homeowners. It also contains the chemical borate which makes it both fire and insect-resistant.

Cellulose insulation has about a 3.5 to 3.8 R-value. It won’t settle too much if you apply it correctly, meaning if you blow in about 10 inches of cellulose insulation, it’ll stay at 10 inches for a longer duration.

While cellulose insulation is mostly irritant-free, we recommend wearing safety gloves and goggles when blowing it into your attic.

Fiberglass insulation

Another popular blown-in attic insulation material is fiberglass. It’s often the cheapest insulation option between the two. It has an R-value of about 2.2 to 2.9 per inch.

Some fiberglass insulation contains as much as 53% of recycled glass which has the added benefit of not settling too much after it’s been installed. It also prevents it from catching fire, making your attic fire-safe.

Best Blown-In Attic Insulation

So which material should you choose for blown-in attic insulation?

Our recommendation for blown-in attic insulation is fiberglass for its lower cost and effectiveness. While every home has different needs, we think this is the most versatile option.

We also recommend the Johns Manville Formaldehyde-free™ fiberglass insulation as the best fiberglass option. It provides thermal and acoustic insulation for your attic, perfect for both vertical and horizontal applications.

The Johns Manville fiberglass insulation is available in a range of R-values to fit any home specifications. It’s perfecting for covering tight spaces, small gaps, or voids. It’s fire-resistant, thermally efficient, and won’t settle after installation.

As the name suggests, Johns Manville’s fiberglass is free of any formaldehyde and can even sound-proof your attic when applied tightly. It won’t corrode into wires or metal studs and is just as fire-resistant as other insulation materials.

How Much Does Blown-In Attic Insulation Cost?

How Much Does Blown In Attic Insulation Cost?

At this point you might be asking: how much will all this cost?

This is a tough question to answer since your blown-in attic insulation budget depends on a few different factors. These include:

  • The state you live in, since R-values vary by location
  • The size of your attic and which areas need insulation
  • The general climate around your home
  • The material you ultimately choose to insulate with
  • Labor and professional equipment costs

Home Advisor estimates that installing blown-in attic insulation costs anywhere from $600 to $1,200 for attics about 1000 square feet in size.

The average home should need an R-value of about 30, which means 10 to 14 inches of total insulation.

Budgeting for Blown-in Attic Insulation

So what’s your budget going to look like for installing blown-in attic insulation?

You first need to look up the recommended R-value that your attic needs to meet. This determines not only which insulation you purchase, but also how much you’ll need to sufficiently cover your home.

Then, you need to look at the cost of labor for installing blown-in attic insulation.

If you do not have the professional experience and equipment for this project, we recommend hiring a professional to handle the work.

Get an Attic Inspection

It’s crucial that you get an attic inspection before buying all the materials and hiring a contractor.

You never know what types of potential issues or considerations are hiding in your attic. Chances are, you don’t really visit your attic all that often. This means there could be all kinds of issues ranging from poor air sealing, ventilation problems, poor air quality, and more.

Attic inspectors can identify these types of issues. They’re also there to show you much insulation you’re going to need based on a number of factors.


Stop unwanted heat transfer and build an energy efficient attic. Leverage this article to know everything you need before embarking on your blown-in attic insulation project.