R-value measures how well insulation resists heat flow — higher is better. Canadian energy codes set minimums by climate zone, and they've risen over time, so older homes are often well below current targets, especially in the attic.
Attic insulation
The attic is the highest-impact place to add insulation because heat rises. Current targets in much of BC call for roughly R-50 to R-60 in the attic. Many older homes have R-20 or less, so a top-up is one of the best efficiency dollars you can spend.
Walls and basements
Walls are harder to upgrade without opening them, but during renovations the cavity and often added exterior insulation bring walls to current targets. Basement walls benefit from insulation too, with attention to vapour control so you don't trap moisture.
Air sealing comes first
Insulation slows heat flow, but air leaks let heat escape outright. Sealing gaps around penetrations, top plates, and rim joists before adding insulation makes the insulation far more effective. Spray foam both insulates and seals, which is why it commands a premium.
BC Step Code
BC is phasing in the Energy Step Code, which pushes new homes toward higher performance and eventually net-zero-ready construction. If you're building or doing a major renovation, ask your designer which step applies in your municipality.