Short answer: closed-cell (R-6 to R-7 per inch, vapour barrier at ~2") is the choice for Alberta basements, crawlspaces, exterior walls, metal and anything moisture-prone; open-cell (R-3.5 to R-3.8 per inch, cheaper, vapour-permeable) suits interior walls and sound. Most homes use both. Here's how to tell which goes where.
R-value per inch
Closed-cell delivers nearly double the R per inch, so it hits a target in less depth - valuable in tight cavities. Open-cell needs more thickness for the same R.
Vapour and moisture
This is the deciding factor in Alberta. Closed-cell becomes a vapour barrier at about two inches and resists water - so it can go below grade and against exterior conditions. Open-cell is vapour-permeable and absorbs water, so it stays interior and dry.
Cost and sound
Open-cell costs less per board foot and dampens sound better. Closed-cell costs more and adds structural rigidity.
The Alberta rule of thumb
Moisture, below-grade or exterior -> closed-cell. Interior walls, sound, budget -> open-cell. A good installer specs the mix. Read the full pages on closed-cell and open-cell, then get a quote.