- Fibreglass batt R-3.5 / in · $
- Spun glass in pre-cut batts — the most common cavity fill in stud walls. Low cost, but performance drops if batts are compressed or leave gaps.
- Cellulose (blown) R-3.7 / in · $
- Recycled paper fibre, blown into attics or enclosed cavities. Fills irregular spaces well; needs vapour control to manage moisture.
- EPS (Expanded Polystyrene) R-4 / in · $$
- White rigid foam board — often used as exterior sheathing in cold climates (as in code-minimum walls). Economical board insulation; protect from water.
- Mineral wool batt R-4.2 / in · $$
- Rock or slag fibre batts. Fire-resistant and good for sound; denser than fibreglass with slightly higher R per inch.
- XPS (Extruded Polystyrene) R-5 / in · $$$
- Closed-cell rigid foam (often blue or pink). Moisture-resistant — common below grade and on exterior foundations.
- Polyiso board R-6 / in · $$$$$
- Foil-faced rigid board with high R per inch among sheet goods. Note: R-value can fall in extreme cold unless specified for your climate.
- Closed-cell spray foam (polyurethane) R-6.5 / in · $$$$$$ Polar system
- Sprayed in place; expands to air-seal gaps while insulating. Highest material cost; requires professional installation. Polar exterior wrap uses this technology for continuous outside insulation.