Understanding Home Energy Loss and How to Reduce It

The attic is frequently the largest single area of heat loss in Canadian homes, particularly in older buildings where insulation was installed to older code standards. Air sealing before adding insulation material is often more important than the insulation itself.

Wall insulation in homes built before the 1980s is often thin or inconsistent. Blown-in insulation through exterior wall cavities can be added without removing drywall, though the effectiveness depends on the wall construction type.

Windows transfer heat through conduction, convection, and radiation. Older single-pane windows perform significantly worse than modern double-glazed units with low-emissivity coatings, especially in Climate Zones 5–8 which cover most of Canada.

Below-grade spaces are often overlooked but represent a consistent source of cold air infiltration. Insulating basement walls and rim joists is generally cost-effective and straightforward compared to other retrofit work.

Gaps around electrical outlets, plumbing penetrations, and poorly sealed attic hatches contribute to air leakage that bypasses insulation entirely. Blower door tests, available through NRCan-registered energy advisors, can identify the most significant locations.

An older furnace or boiler operating below its rated efficiency loses energy before it even reaches living spaces. Pairing a high-efficiency unit with proper duct insulation reduces distribution losses, which can be as high as 30% in some systems.