Three of the most common Insulation options are fiberglass, spray foam, and cellulose insulation.
So we did an in-depth comparison where we put fiberglass insulation vs spray foam vs cellulose insulation to the test to find out which of the three is the most cost-effective, which is the most eco-friendly and which one actually does the best job at keeping your home warm.
Spray Foam Insulation
First, spray foam. Spray foam insulation has been an important sustainable material for builders interested in improving a home’s energy performance. In fact, spray foam offers some of the highest thermal resistance, or R-value, of any insulation option. Its LTTR (long-term thermal resistance) is also excellent.
In this post, we’ll walk you through the basics of spray foam insulation and offer some practical and environmental considerations to help you decide whether this technology is your best bet to insulate your home.
What Is Spray Foam, Exactly?
Spray foam is made of a number of liquid chemicals—what people call an A side and a B side—that are kept apart until it’s time to apply the foam.
Side A is made of isocyanates. Side B contains polyol resins, which react with the isocyanates to create the foam, as well as catalysts, surfactants and flame retardants. Finally, the mixture contains a blowing agent that creates and expands the “cells,” or bubbles, that give the foam its insulating properties.
How Well Does Spray Foam Insulate?
It all depends on the type: open cell or closed cell. The R-value of closed-cell foam averages about R-6.5. Open-cell spray foam, however, comes in around R-3.5.
In open-cell foam, the cells aren’t fully self-contained. That makes the product softer and more flexible. The bubbles in closed-cell foam are fully enclosed and packed tight, so the foam has a greater structural stability.
Rob Yagid of Fine Homebuilding offers some in-depth comparisons of the properties of each. The most important differences are a result of differences in density.
Yagid explains that open-cell spray foam has a density of ½ pound per cubic ft. Closed-cell foam, however, is 2 pounds per cubic ft. That density, he says, “increases its R-value and offers it the rigidity that open-cell foam lacks.”
The increased density of closed-cell spray foam also makes closed-cell foam an effective air and vapour barrier. Open-cell foam, on the other hand, is breathable and permeable to vapour.
You might be thinking at this point that since the density of closed-cell foam offers higher R-values, vapour stopping qualities and even boosts the structural integrity of the wall, it’s the better option. There are advantages to a less dense insulation, however.
Density also determines the volume the product can reach, and, therefore, how economical it is to apply.
Open-cell foam expands about 3 times as much as closed-cell spray foam. That means that it’s better able to reach into cracks, corners and difficult spaces. You’ll need less open-cell foam to fill spaces, and that makes it more budget friendly. Open-cell spray foam also offers some soundproofing qualities.
Quick, Practical Considerations for Homeowners
Open-cell foam can be applied all in one go and dries faster, while closed-cell foam needs to be done in layers to give it time to cure.
Because open-cell foam is permeable, it can absorb water. That makes it not a great choice for damp environments like basements and crawlspaces.
More spray foam isn’t necessarily better. Yagid notes that after a point, adding more of either kind of foam will only fractionally improve efficiency. “In fact,” he says, “while the cost of an R-40 wall is indeed double that of an R-20 wall…it reduces the conductive heat flow through a wall by only an additional 2%.”
That cost-benefit consideration is especially important for those on a budget, because there’s no way to keep costs down by DIYing this project.
Why You Shouldn’t DIY This Project
First, it’s made of toxic chemicals and you need professional safety gear and equipment to apply it. Second, it’s complicated to mix correctly. The ratios need to be measured exactly, otherwise, the insulation a) won’t perform as well, and b) might not cure correctly, which leaves unreacted chemicals that can cause health and environmental risks.
Foam also gets hot as it cures. Applying layers that are too thick risks overheating the product and damaging the insulation, not to mention any wiring or plumbing covered by the foam.
Novices are likely to be inefficient with the product, as well (which sounds judgy, but that’s not how we mean it). Inefficient application leads to greater waste and therefore greater costs (both financial and environmental).
Environmental Considerations of Spray Foam Insulation
Spray foam insulation is extremely good at making a building energy-efficient, but it’s not without its issues. The biggest concerns are its embodied energy and the chemicals involved in its creation and installation.
Polymeric methylene diphenyl diisocyanate (pMDI) and polyol are both petroleum products that are extremely energy-intensive to produce. There is, therefore, a certain irony to relying on them in the quest to use fewer fossil fuels for heating.
The chemicals that make up spray foam, namely isocyanates, amine catalysts, ethylene glycol and flame retardants such as hexabromocyclododecane (HBCD or HBCDD) and tris (1-chloro-2-propyl) phosphate (TCPP), are toxic and persistent.
The blowing agent has been a particular concern. Recent foams have used HFCs as blowing agents, and these chemicals have extreme global warming potential (GWP).
Construction Canada explains that since January of 2021, HFCs have been banned in Canada. The replacement chemicals are hydrofluoroolefins (HFOs), which according to Construction Canada are “a substance with near zero contribution to both ozone depletion and greenhouse gas (GHG) emissions.”
As an environmentally-minded consumer, however, you’ll need to ask what a given product contains until HFCs are phased out completely.
Another environmental factor to consider is that these products cannot be recycled or repurposed at the end of their lifespans.
If you know you want a spray foam, look into bio-based foams that use water as a blowing agent and materials such as soybean or castor oil as a base.
Each manufacturer will use a different percentage of plant-based oil and different chemical components, so be aware that not all bio-based foams are equivalent. This 2021 study offers a wealth of information on promising new materials, if you’re interested.
What Is Fiberglass Insulation?
Fiberglass insulation, otherwise known as fiberglass batts, is one of the most common types of insulation used for residential purposes.
For the record, fiberglass insulation also comes as loose fill, not just in the form of batts. These are not interchangeable terms, but the batt variety is the most popular, so it’s what we’re focusing on here. It actually looks like the pink cotton candy you might get from a carnival (except fiberglass insulation is definitely not edible!).
If you see that your walls contain thick layers of these pink hairs, you have fiberglass in your walls. Be sure not to touch it, because it is extremely itchy and irritating.
Fiberglass is made by taking very thin glass fibers and spinning them together before placing them in between foil backing or paper backing.
The fiberglass batts are then cut to standard sizes that can easily fit between framing studs in walls and ceiling joists. Fiberglass batts roll out very quickly and are easy to install, which is why they are often a preferred method of insulating.
Any HVAC or insulation contractor can easily install fiberglass insulation without any special tools or skills. And it’s even something a homeowner could do on their own without any specialized knowledge.
How Well Does Fiberglass Insulate?
Your average fiberglass batts have an R-factor of 3.2 per inch. This is definitely good enough for basic insulation purposes, but that R-factor is the lowest of all three types of insulation we’re examining today. Yes, it works fine for most purposes, but it’s probably not something you’d want to use to insulate your house if you live in the Arctic.
Another issue is that fiberglass batts don’t often fit together very well when being installed, which may leave some small gaps for air to pass through.
How Cost Effective Is Fiberglass Insulation?
As mentioned above, one of the main reasons why so many people choose fiberglass insulation is quite simply because it is cheap. Generally speaking, you can expect to pay anywhere between $0.88 and $1.64 for each square foot that you wish to cover with fiberglass insulation.
In the grand scheme of things, this is actually very cost effective, at least as far as the initial installation is concerned.
As mentioned above, fiberglass insulation has a moderate low R-value, which means that its insulating capabilities, while acceptable, aren’t fantastic. The lower the R-value of the insulation, the higher your heating costs will be in the winter and the higher your cooling costs will be in the summer.
Since fiberglass has the lowest R-value of the three options being tested, your heating and cooling costs might make this option less cost-effective than it first appears.
Environmental Considerations With Fiberglass Insulation
One of the good things about fiberglass insulation in terms of environmental considerations is that it can last up to 100 years, so it saves you and the environment from having to replace it with new insulation material.
Furthermore, fiberglass is technically biodegradable, and it does decompose, albeit after a very long time. Fiberglass is technically recyclable, as it can be ground and shredded for use in other products. If you need to get rid of it, look up some recycling locations in your area to see if you might be able to drop it off.
On the other hand, the production of fiberglass is certainly not good for the environment, as it produces a variety of extremely toxic emissions and air pollutants. One of the most common toxins released during the manufacturing process is styrene, which is a carcinogen. Other volatile organic compounds or VOCs are also released during the manufacturing process, which pollute the environment.
What Is Cellulose Insulation?
Cellulose insulation is very different, as it is a loose fill type of product that is made out of extremely small and pulverized particles of cloth and paper, which is then treated with a fire retardant. Using hoses with massive amounts of air pressure, it is then blown into attic and wall spaces.
Once in place, it looks like fresh and loose snow. It’s really just an extremely thick layer of shredded paper and cloth. It’s not the most expensive type of insulation, although it is slightly costlier than fiberglass.
What many people like about fiberglass insulation is that it can be blown into existing walls without having to dismantle them. At the same time, cellulose insulation also provides some soundproofing benefits.
That said, this is not something you can do on your own because it requires special equipment and knowledge. Another factor to consider is that cellulose insulation, if it gets wet, may suffer from mold growth, which would mean that it would have to be removed and replaced.
How Well Does Cellulose Insulate?
Cellulose insulation performs quite well, as it features an R-factor of 3.8 per inch, which is higher than fiberglass insulation.
Moreover, due to the nature of cellulose insulation, it packs into tight spaces more easily, leaving fewer gaps than fiberglass does. Cellulose works really well at preventing heat transfer and it also blocks air leakage very well.
How Cost Effective Is Cellulose Insulation?
Cellulose insulation is slightly more expensive than fiberglass insulation. On the lower end of the spectrum, it might cost around $0.60 per square foot, but it can also cost up to $2.30 per square foot, depending on the quality, the brand and the company doing the insulating.
If you go for the most expensive option, then it will be significantly more expensive than fiberglass insulation.
Due to its higher R-factor, however, you will save more money on energy costs in the long run than with fiberglass insulation. The question is simply how long it takes for the cost of the cellulose insulation to pay for itself in terms of energy savings when compared to the much lower initial cost of fiberglass insulation.
Environmental Considerations With Cellulose Insulation
In terms of being ecofriendly, there is no doubt that cellulose is by far the most eco-friendly of all three types of insulation compared here. Cellulose insulation is most often made out of recycled materials like recycled paper and recycled cloth.
This helps to keep these materials out of landfills and prevent the production of greenhouse gases. Organic materials like paper and cloth rot and decompose, and the decomposition process releases greenhouse gasses into the air. By recycling these materials instead of letting them decompose, this issue of greenhouse gas production can be avoided.
Also, consider that it does insulate quite well, so not only will you save money on energy costs, but you’ll also consume less energy, therefore helping the environment.
Furthermore, once cellulose insulation reaches the end of its lifespan, because it is made out of biodegradable cloth and paper, it won’t have a huge impact on the environment.
New types of eco-friendly spray foam insulation may be just as environmentally friendly as cellulose insulation, although at this time, cellulose is still best in terms of environmental impacts because it’s both made of recycled materials and fully biodegradable.
Eco-Friendly Options
If none of these three options sounds sustainable enough for you, there are alternatives you can check out.
Read our guide to the ‘Best Insulation Choices for Green Building‘ to learn about renewable insulation options like sheep’s wool or recycled options, which allow you to get the best of both worlds: high-quality insulation that is also sustainable.
Fiberglass vs Spray Foam vs Cellulose—Key Takeaways
Let’s just quickly go over a few very important points that you need to know about fiberglass, spray foam and cellulose insulation.
- When it comes to fiberglass batt insulation vs spray foam, the fiberglass is far cheaper to install, but the foam does a much better job at insulating.
- In terms of cellulose insulation vs spray foam, the foam also does a much better job but is more expensive.
- If we compare cellulose to fiberglass, cellulose is more eco-friendly and better at insulating, but it may not have as long of a lifespan and costs more for the initial installation.
What it really comes down to is that fiberglass is the cheapest option, cellulose is the most eco-friendly option and spray foam does the best job at insulating.
Cellulose has a much lower impact on the environment than either of the others. It can be made with 100% recycled materials, is biodegradable and doesn’t involve a very harmful or chemical-laden manufacturing process, especially when compared to foam and fiberglass.
As you’re making your choices, consider talking to other people about them, and pushing companies and governments for better options when it comes to insulation. Those discussions, alongside your efforts to make your home greener, will move the needle towards a more sustainable world.
Feature image: Vidar Nordli Mathisen; Image 1: Anna Biasoli; Image 2: Hans Isaacson
The post Which is Most Sustainable and Effective: Fiberglass Insulation vs Spray Foam vs Cellulose Insulation appeared first on Green Building Canada.
The post Which is Most Sustainable and Effective: Fiberglass Insulation vs Spray Foam vs Cellulose Insulation appeared first on Green Building Canada.
This post first appeared on GREEN BUILDING CANADA | Green Building Directory,, please read the originial post: here
