Insulation is one of the primary barriers in the thermal envelope and foam insulation has recently seen a surge in homeowner interest. It’s easy to understand why.
The question is, is foam insulation worth it and what are the pros and cons of choosing foam insulation? I’ve researched this extensively I’ve learned that there is a formula for making this buying decision.
Is foam insulation worth it? There are several factors that will determine if spray foam insulation is worth it for you. These include:
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- How long you will live in the house
- Type, age, and efficiency of your central air and heating
- You do not have open combustion appliances or furnace
- You understand the health concerns over foam spray insulation
- You have the additional money required for the investment
My goal is to provide you with factual, unbiased information that can help you to make an informed decision. I am not here to sway you one way or the other. I want to educate
I’ll back up my information with references so that you can do your own homework. Deciding on Spray Foam insulation in your home is a big investment and so it is a big decision.
Ultimately, I’ll share with you why I chose not to go the foam insulation route in my home based on the criteria I listed above.
What Are The Benefits Of Spray Foam Insulation?
The ultimate benefit of spray foam insulation is that it provides a more energy efficient thermal envelope. This means less conditioned air escapes out of the structure. The result is a comfy home and lower energy costs.
Spray foam insulation provides a superior R-value per inch compared to traditional rolled or blown in insulation. According to diffen.com, spray foam insulation provides an R-value of 6 for every inch of insulation installed. By contrast, the R-value for fiberglass is closer to 2.2 per inch to 3.5 per inch depending on the source. Regardless, rolled and blown in insulations do not compare to the air resistance value of foam spray
Because it is sprayed on wet and expands as it drys, spray foam insulation has the added benefit of expanding into cracks and sealing air leaks in the thermal envelope, Energy Star reports that 25-40% of conditioned heating and cooling costs are lost through air leaks in the average home.
Spray foam also contributes to the structural strength of a home. It’s true!
This applies to closed-cell foam spray (more on the distinctions between open and closed cell later) but I found multiple non-commissioned reports including this one from the National Frame Building Association that support claims of increased structural strength, citing multiple research sources.
Moisture resistance is yet another benefit of spray foam over fiberglass or cellulose. This applies primarily to closed cell foam. In fact, Business Science Consulting reported that this type of foam insulation actually serves as a viable secondary rainwater barrier.
And get this, FEMA has classified spray foam insulation as having the highest resistance to flood damage. Fiberglass and cellulose are both classified as “unacceptable” regarding these criteria.
So yeah, spray foam is pretty awesome. It provides substantial energy saving benefits and thermal envelope sealing.
Open Cell vs. Closed Cell Spray Foam Insulation
It’s important to understand the differences between the two primary types of spray foam insulation.
Open cell spray foam offers less R-value and less moisture barrier protection than closed cell. It has to do with the way the foam cures as it dries. Open cell foam dries “semi-permeable”, meaning it allows for at least some air (and moisture) to move through it. Closed-cell foam dries to a non-permeable state allowing virtually no air or moisture movement through it.
What Are The Concerns With Foam Insulation?
Spray foam insulation should be professionally installed in most situations. Although it is possible to do this as a DIY project, proper and precise chemical mixing is essential to ensure a safe and effective application. Failure to adhere to manufacturer guidelines can result in prolonged odors, oily residue, and poor insulation/air-sealing. Read this post from Eco Three for examples of spray foam gone wrong.
It is also important to understand that there are certain health concerns related to spray foam insulation. The Environmental Protection Agency published this report related to an ingredient in the spray foam called Isocyanate. According to the report, this chemical can cause a multitude of health issues including respiratory infections, asthma, and skin irritation.
Just be aware of what you are putting into your home and do your due diligence.
Is Foam Insulation A Good Energy Efficiency Investment?
There are several factors
How Long Will You Live In The House?
It will take a few years for you to see a return on your investment. Assuming you spend an extra couple of thousand dollars for spray foam over fiberglass or cellulose, you will want to make sure that you are going to live in that house long enough to see the investment pay off.
Type, age, and efficiency of your central air and heating
When considering spray foam insulation for my own home that I was building, I learned that the HVAC system that I was planning to install would not be appropriate.
Because of the extreme air-sealing of the thermal envelope resulting from a spray foam insulated house, adjustment to the sizing and type of central air and heating unit is needed. Too large of a system runs the risk of decreased efficiency and increased moisture.
EcoLogic has an explanation of this that you can read here. Depending on the age and efficiency of your current unit, you may need to upgrade which could be quite costly.
You do not have open combustion appliances or furnace
This one caught me by surprise but it could be a deal-breaker. There are two types of gas appliances; open combustion and sealed combustion.
Open combustion appliances take air from the area around them. They are also referred to as atmospheric combustion appliances. When you air-seal a home as tightly as spray foam insulation does, you can create a vacuum essentially. Read this article from Energy Vanguard to understand this better.
You understand the health concerns over foam spray insulation
As explained earlier, spray foam insulation is not without its potential health concerns. Ensure that you are informed and educated on what the potential risks are and weigh those against the benefits.
At the same time, there are thousands of homeowners enjoying the benefits of energy efficiency that spray foam insulation provides. Knowing the facts and making an informed decision will be based on your comfort level with the reported health concerns.
You have the additional money required for the investment
Spray foam insulation costs more than traditional insulation approaches such as fiberglass and cellulose. The potential energy savings can certainly justify that investment but the bottom line is that you will need more money up front.
Alternative Energy Saving Solutions
After conducting exhaustive research and some late night pondering, I chose not to use spray foam insulation in my new house. The reason for this was a mixture of the factors I outlined above.
First, my family did not expect to live there for more than five years so the return on investment just wasn’t there. Second, having a young son living in the house with me, I just couldn’t balance the potential health concerns with the potential energy savings.
At the same time, I am fanatical out energy savings. This was a difficult decision for me. What I did instead, was to focus on alternative energy saving solutions.
One of the key benefits of spray foam insulation, as I stated earlier, is the tightness of the thermal envelope. You can still make significant improvements in your home’s energy efficiency by air sealing around windows, doors, outlets, light fixtures, and vents. To learn more about air-sealing, read my article Is My Home Energy Efficient? Here’s How To Know!
Energy Star reports that “air sealing the building envelope is one of the most critical features of an energy efficient home“.
Installing a radiant barrier in your attic is a DIY project that can be completed over a weekend. It comes in rolls and staples up quickly. There is a ton of research on the effectiveness of radiant barriers. I am in the process of installing it in my attic. Below is a picture of the progress I have made along one roofside.
Read this report from the Department of Energy on radiant barriers for more information.
Making the right decision on spray foam insulation requires consideration of the facts and an understanding of the benefits and concerns. Take the time to research. This is a large investment and you want to make the decision that is right for you and your family.
If you would like to understand the energy efficiency of your home, please read Is My Home Energy Efficient? Here’s How To Know!
You can also conduct a free energy efficiency audit of your home using my instructions and downloadable checklist.