Highly Energy Efficient Building Envelope Retrofits for Houses, a free downloadable Research Highlight recently released by Canada Mortgage and Housing Corporation (CMHC), provides design and construction information for retrofitting existing residential wood frame building envelopes to reduce space heating energy use by 75 per cent or more. The report may have significant implications for the housing and renovation industry – it concludes that building envelope insulation and airtightness retrofits can lead to significant reductions in energy consumption and can be cost-effective in comparison with renewable energy systems. The paper investigates high insulation building envelope retrofits; develops targets for insulation and airtightness values for foundations, walls, windows, doors and roofs; considers building code and zoning implications of changes to the building envelope; and presents details and specifications of practical retrofit strategies for common housing archetypes.
