For Alberta's cold, the best insulation is the one that air-seals AND holds a high R-value - because in a cold, windy climate the air leaks cost as much as the missing R. That points to closed-cell spray foam where it counts, with open-cell and blown-in filling supporting roles.
Why air-sealing leads here
A high R-number means little if wind drives cold straight through the gaps around the insulation. Alberta's cold is long and often windy, so stopping infiltration is half the battle - and only foam air-seals as it insulates.
The smart mix
- Closed-cell (R-6-7/in, vapour barrier): basements, rim joists, exterior, metal, below-grade.
- Open-cell / blown-in: interior walls, sound, budget attic depth (ideally over a foam air-seal).
The bottom line
There's no single winner - there's the right material per assembly, with the air-seal prioritized where the climate punishes leaks. Get a quote and have an installer spec the mix.