Canada’s Energy Rating (ER) system rates windows differently from US U-factor. Higher ER = better performance. ENERGY STAR in Ontario requires ER >= 29. Budget windows often sit at ER 15-20 – functional but costly to operate.
Frame materials:
- Vinyl (uPVC): Most popular in Ontario, good thermal break, mid-range cost
- Fiberglass: Best thermal performance, premium price
- Wood: Highest aesthetics, requires maintenance
- Aluminum: Poor insulation unless thermally broken – avoid for Ontario climate
Double vs triple glazing:
- Double-pane low-E argon: ER 28-35, adequate for most applications
- Triple-pane: ER 38-50+, recommended for north exposures, noise reduction, near-net-zero targets
GTA cost ranges (supply and install, 2026):
- Standard double-hung vinyl: $600-$900/window
- Casement double-pane: $700-$1,100
- Triple-pane premium: $1,000-$1,800
- Full-house (15-20 windows): $12,000-$25,000
Greener Homes Grant: Up to $250/window, max $5,000. ENERGY STAR certification required.
Note: installation quality matters as much as product spec. Air leakage around the frame – not through the glass – is the primary heat loss path.
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