Differentiating Between Blown-In and Spray Foam Insulation

Differentiating Between Blown-In and Spray Foam Insulation

How To
By Dikran Seferian February 23, 2022

Insulation is a vital element that provides the comfort needed to make our homes livable space. It is also known to be highly beneficial for maintaining the energy efficiency of a household, making it easier to regulate indoor temperatures throughout the year. Whether you’re looking to upgrade your home’s insulation or insulate a new house, you may want to go for something that’s durable, sustainable, and high-quality.

Two common options among many homeowners are spray foam and blown-in insulation. Both of these insulating materials are great in their own ways. While spray foam has a higher R-value, for instance, blown-in cellulose has better noise-canceling properties. Comparing these two options will allow you to choose the one that’s best for your home.

What Is Blown-In Insulation?

What Is Blown-In Cellulose and How Is It Installed?

What Is Blown-In Cellulose and How Is It Installed?

One type of insulation you could consider is blown-in cellulose. Essentially composed of plant fibers or wood-based material, it is filled within roof cavities as well as walls. Sisal and corn plants are often used in the production of cellulose insulation. Commercial varieties, however, make use of recycled newspaper, cardboard, office paper, and waste paper. This makes blown-in insulation an eco-friendly way to maintain the comfort of your home while saving energy.

As the name suggests, this type of insulation is blown into the walls — usually before finishing the construction. This doesn’t, however, mean that you can’t insulate a priorly built house using this method. Should you want to, the job will involve drilling a hole in the interior wall or the exterior siding, and inserting a nozzle into that hole to fill it with the insulating material. Once the wall is filled with cellulose, the professional will patch up the hole so you could hardly tell it was there.

Many homeowners may even choose to apply blown-in cellulose insulation in addition to pre-existing fiberglass batts. Not only does this reinforce the insulation, but it also helps in sound dampening.

What Is Spray Foam Insulation?

All You Need to Know About Spray Foam Insulation

All You Need to Know About Spray Foam Insulation

Spray foam is a type of insulating material that consists of polyol resin and isocyanate. Polyol is a form of hydroxyl compound whereas isocyanate is a substance that’s usually found in surface coating to manufacture solid foams.

Upon applying the spray foam, it doesn’t really seem like much. However, you’ll notice that it begins to expand rather quickly. The material will initially be in liquid form and will increase up to 60 times in volume after its application, eventually becoming solid.

One of the most significant features of spray foam insulation is its thermal resistance — which is why it’s a go-to option for many homeowners.

The way heat transfers can either be convective, radiant, or conductive. The first refers to sources of heat being brought into the home by air or water. Radiant transfer, on the other hand, is when less reflective surfaces absorb the heat energy from warm surfaces. Lastly,  conductive transfer is the way thermal energy moves among substances when one has a higher temperature than the other.

Spray foam insulation can effectively hinder all three of these ways — hence its high R-value rating. The R-value measures how well a form of insulation can block the flow of heat.

Types of Spray Foam Insulation

There are two forms of spray foam insulation that you can choose from — open and closed. These refer to the state in which the cells are within the material.

Open-cell spray foam allows for a softer and more malleable insulation. It is the ideal option for tight nooks in the attic as well as oddly shaped crannies in the basement. Closed-cell spray foam, on the other hand, has a harder and more solid texture. This is due to the absence of moisture and air in the cells. While this option is more durable, it’s not meant for the tighter spaces.

Pros and Cons of Blown-In Insulation

Weighing the Pros and Cons of Blown-In Insulation

Weighing the Pros and Cons of Blown-In Insulation

As with any type of insulation, blown-in cellulose has its own set of advantages and disadvantages. These mostly have to do with the durability, effectiveness, as well as other aspects of the material.

Advantages of Blown-In Insulation

  • The material used in blown-in insulation is fire-resistant, giving the homeowner peace of mind.
  • Blown-in cellulose is generally eco-friendly. In certain cases, however, the material might be treated with a chemical known as borate, reducing its eco-friendliness as a result.
  • Other than thermal insulation, cellulose is also great at minimizing the amount of noise that comes from outside. This makes your living spaces somewhat more peaceful.

Disadvantages of Blown-In Insulation

  • The R-value of blown-in cellulose is slightly lower than that of its spray foam counterpart. That is why this type of insulation requires more space and material to achieve the R-value of spray foam.
  • Having to drill holes into the wall in order to insulate a readily built house might seem rather inconvenient — although it’s perfectly feasible. 
  • Loose insulating material can eventually settle to the point where it forms pockets, allowing warm or cold air to seep in. This tends to reduce the effectiveness of the insulation.

Pros and Cons of Spray Foam Insulation

Why You Should Go for Spray Foam Insulation

Why You Should Go for Spray Foam Insulation

Just like its blown-in counterpart, spray foam insulation also has a number of upsides as well as downsides to take into consideration.

Advantages of Spray Foam Insulation

  • Spray foam gives you the option of choosing between open-cell and closed-cell, which matters depending on where you’re applying it.
  • Spray foam insulation has a significantly high R-value, allowing it to hinder all three forms of heat transfer.
  • Applying spray foam is fairly easy, especially in tight spaces.

Disadvantages of Spray Foam Insulation

  • Spray foam contains hazardous chemicals that you might want to be careful of when installing the product.
  • Each square foot of spray foam may cost up to $1.50 on average. This makes it more of an expensive option than other insulation materials. 

How to Choose Between Blown-In and Spray Foam

Deciding between blown-in cellulose and spray foam insulation really depends on the qualities that you’re looking for. If the R-value is important to you, for instance, then the best choice is spray foam — particularly the closed-cell variety as it has a higher R-value than open-cell foam. Interestingly enough, cellulose has an R-value of 3.5 for every inch whereas open-cell spray foam is rated at 3.7 an inch. The more notable difference, however, is with closed-cell foam which boasts an R-value of 6.5 per inch.

Prioritizing the R-value is especially important if you live in regions where temperatures are often soaring. Houses in Florida, for instance, are known to get notoriously hot. An insulating material that can effectively resist such an amount of heat will be necessary — spray foam being the obvious choice.

Closed Cell Spray Foam Can Be Ideal For Regions With Soaring Temperatures

Closed Cell Spray Foam Can Be Ideal For Regions With Soaring Temperatures

If you live in a noisy neighborhood and could use a little peace and quiet in your home, you might want to go with blown-in cellulose. The noise-canceling properties of this insulation material will prevent you from having to hear cars passing by, the neighbor’s dog barking, and other outdoor hubbub. You may, however, still hear these sounds to a small extent, but certainly not as loudly as you would without blown-in insulation.

Spray foam, on the other hand, doesn’t really help in soundproofing your home. This might not be much of an issue if you live in a quiet area. But if your relaxation is constantly disrupted by street noise, you may want to consider blown-in cellulose.

Another factor to account for is the safety of the insulating material when it comes to your health. Blown-in cellulose is generally safer than spray foam, but only if it consists of completely recycled material. Cellulose that’s chemically treated with borate is just as unsafe as any other form of insulation. Spray foam, on the other hand, is known to irritate those who have respiratory issues like asthma. This is less likely to happen with blown-in insulation. In any case, make sure to wear safety gear should you be applying the insulation yourself.

In terms of price, you won’t see much of a difference between blown-in and spray foam insulation. The average cost of blown-in cellulose is $1.20 per square foot whereas foam spray is only slightly more expensive ($1.50 per square foot). If you’re on a tight budget, you’ll find a cheaper option in fiberglass.


Written by
Dikran Seferian

Written by Dikran Seferian