Myth Busting: All Spray Foam Insulation is Created Equal

Spray foam has become a popular product for insulating homes, especially difficult-to-insulate spaces like basements. Spray foam is an effective insulator because not only does it have a high insulating value (R-value per inch), it also conforms to rough surfaces and stops air leakage. And it’s quick to install by a professional insulation company. But there’s something you need to know if you are thinking about using spray foam.

Not all spray foam is created equal.

Many brands of spray foam on the market today have an agent in them with a large impact on global warming, making the climate crisis worse. The good news is - a few companies have solved this problem and have products you can choose from that are much better for the environment. To understand the difference, we need to dig into a deeper explanation.

Typical spray foam is polyurethane foam or similar. Polyurethane foam is the same stuff used in soft, cushy furniture like couches and chairs, but for insulation, it is made harder. It comes in open-cell or closed-cell. Open-cell, sometimes called half-pound foam, is lighter and does not act as a vapor barrier, but it still slows down air leakage. Closed-cell, sometimes called two-pound foam, is denser and acts as both an air and vapor barrier. Closed-cell foam is an effective insulator for foundations and any place that needs a vapor barrier.

Off the Charts Bad for the Environment

The environmental problem is called the blowing agent, especially for closed-cell foam. Every foam needs a blowing agent; it makes the cells or bubbles that make it a good insulator. But some of the blowing agents escape to the atmosphere when the foam is sprayed in. Once in the atmosphere, if the agent has a “high global warming potential,” it will cause global warming to accelerate, speeding up the global climate crisis that we all face. The solution is to look for spray foam with a low global warming potential.

Global warming potential (GWP) is chemistry-speak for “how bad is it for the climate?” compared with other gases. On this scale, carbon dioxide (CO2) from burning fuel is defined as the base of the scale with a GWP of 1. Methane (CH4) has a GWP of 28, meaning that when methane escapes into the atmosphere, it is 28 times more powerful at accelerating climate change than carbon dioxide on a per kilogram basis.

 Methane is bad enough at a GWP of 28. But the blowing agents in many spray foams are off the charts, with GWP in the thousands! The average GWP of the most commonly used blowing agents, called hydrofluorocarbons (HFCs), is over 3400.1. Each kilogram of these agents is as bad for destabilizing the climate as a whopping 3.4 tonnes of carbon dioxide.

Look for Low GWP Spray Foam

What does this mean? It means if you use a spray foam with a high GWP, you will cause climate change to get worse. The energy you will save by being better insulated will eventually make up for this. Still, it could take up to a decade, in some cases longer, to break even from an environmental perspective. You would be saving money, but not the environment.

The good news is that spray foams are available now with a much lower GWP without sacrificing effectiveness. Choosing one of these low-GWP foams will make you an environmental and economic hero at the same time.

Here is an example from the author’s own basement in Halifax, Canada. This basement needed insulating to cut heat loss and dampness, and spray foam was an effective way to insulate it. I chose a spray foam with low GWP (Insulthane ExtremeTM). The comparison with another high-GWP product in this table shows why.

By the Numbers

The low-GWP foam, in this case, Insulthane ExtremeTM, wins the environmental competition hands-down. They’ve achieved this using the SolsticeTM blowing agent developed by Honeywell. Other spray foam manufacturers are starting to adopt low-GWP blowing agents too.

Cost?

What about the cost? In the case above, the cost of the two examples is almost the same. The low-GWP foam often costs a bit more and may have a higher R-value per inch, so less foam is needed. The result, in this case, is a total price of about the same. For about the same cost, you can make a much greater environmental benefit by choosing a foam with low global warming potential.

If you consider using spray foam to insulate, ask for spray foam with low global warming potential. This is an easy win for you and the environment.

Source for global warming potential data:

1 Second Assessment Report on Climate Change, Intergovernmental Panel on Climate Change, 2007.