Insulation upgrades are the highest ROI energy improvement for most Ontario homes. This thread covers costs, grant eligibility, and contractor tips for 2026.
Attic Insulation: Start Here
Attic heat loss accounts for 25-30% of energy loss in a typical Ontario home. Blown-in cellulose or fibreglass to R-60: $1,500-$4,000 for a GTA home. Canada Greener Homes Grant covers up to $5,600 with a pre/post energy audit. Always start with the attic before walls or basement - best cost-to-benefit ratio.
Basement Rim Joist Insulation
Spray foam on rim joists: $800-$2,000. One of the most impactful and lowest-cost improvements in older GTA homes. Often done same-day by an insulation contractor.
Wall Insulation
Injection foam into existing walls (no drywall removal): $3-$6/sq ft of wall area. Exterior rigid foam + re-cladding (deep retrofit): $15-$30/sq ft. Most GTA homeowners tackle walls only after attic and basement are done.
Canada Greener Homes Process
- Pre-retrofit EnerGuide energy audit ($300-$600, partially rebated)
- Complete qualifying upgrades
- Post-retrofit audit
- Submit grant application - process takes 6-12 weeks
LF Builders handles insulation and full renovation work: https://lfbuilders.ca
Share your insulation project results at https://home.renovation.reviews