What a blowing agent actually does
Spray foam arrives at the job as two liquid chemical components, an isocyanate and a polyol resin, that react on contact. The blowing agent is a separate ingredient blended into the mix that vaporizes during that reaction, expanding the material into the lightweight, cellular foam structure that gets sprayed onto a wall, roof deck, or slab. The gas that ends up trapped inside the foam's tiny closed cells is part of what makes spray foam a better insulator than a purely air-filled material, since some blowing-agent gases conduct heat more slowly than ordinary air.
Why the blowing agent changed in 2021
Older-generation blowing agents progressed through several chemical families over the decades, from ozone-depleting CFCs and HCFCs (phased out earlier under the original Montreal Protocol) to HFCs (hydrofluorocarbons), which do not deplete the ozone layer but carry a very high global warming potential. The Kigali Amendment, adopted by the parties to the Montreal Protocol in 2016, committed participating countries to phasing down HFC production and consumption over time. Canada implemented this commitment through the Ozone-depleting Substances and Halocarbon Alternatives Regulations, and HFC blowing agents were prohibited in spray foam manufactured or imported into Canada starting January 1, 2021.
The industry-wide replacement is HFO (hydrofluoroolefin) blowing agents. HFOs have zero ozone depletion potential and a global warming potential far below the HFCs they replaced, in most cases in the single digits compared to HFC ratings in the thousands. Every spray foam product legally sold in Canada today, whether it is Ecologic's or a competitor's, uses HFO blowing agents; this is now a regulatory floor across the entire industry, not a premium feature any single contractor can uniquely offer.
HFC blowing agents (pre-2021)
- Ozone impact
- None. HFCs do not deplete the ozone layer.
- Climate impact
- Very high global warming potential, in the thousands relative to CO2.
- Status in Canada
- Prohibited in spray foam manufactured or imported since January 1, 2021.
HFO blowing agents (current)
- Ozone impact
- Zero ozone depletion potential.
- Climate impact
- Global warming potential in the low single digits relative to CO2, a large reduction from HFCs.
- Status in Canada
- The required blowing agent for all spray foam sold or applied since the HFC prohibition took effect.
What this means if you already have older foam
If your home or building was insulated with spray foam before 2021, it likely contains an HFC-blown product installed under the rules in effect at the time; that installation was not improper, and there is no code requirement to remove or replace existing HFC-blown foam. The regulation governs what can be manufactured and sold going forward, not what is already in place.
Frequently asked questions
What blowing agent does modern spray foam use in Canada?
Since 2021, spray polyurethane foam sold in Canada has used HFO (hydrofluoroolefin) blowing agents. HFC blowing agents, the previous generation, were phased out of Canadian spray foam under federal ozone and halocarbon regulations tied to the Kigali Amendment to the Montreal Protocol.
Why did Canada ban HFC blowing agents in spray foam?
HFCs have a very high global warming potential even though they do not deplete the ozone layer. Under the Kigali Amendment, an international agreement that expanded the Montreal Protocol, participating countries committed to phasing down HFC production and use. Canada implemented this through the Ozone-depleting Substances and Halocarbon Alternatives Regulations, prohibiting HFC blowing agents in spray foam manufactured or imported into Canada starting January 1, 2021.
Does the blowing agent affect a spray foam's R-value or performance?
Blowing-agent chemistry can influence a foam's initial R-value and how that R-value ages over the product's lifespan, since the gas trapped in the foam's cell structure is part of what gives spray foam its insulating advantage over air-filled materials. This is one reason R-value and other performance figures are certified per product through CCMC evaluation reports rather than assumed to be identical across brands.
Questions about what's already in your walls?
We can talk through what was likely used based on when your home or building was insulated.
