Conditioned air is escaping or outside air is infiltrating around gaps between the building structure and window frames. In either case heating and/or air conditioning energy is lost, comfort is reduced (drafts in winter), and the life expectancy of building components is reduced by this uncontrolled migration of air and moisture through the building envelope.
A commercial grade exterior silicone caulk should be applied around the entire perimeter of the window frames in the areas identified:
This recommendation is in accordance with Measure HV10 of the CMHC manual on Energy and Water Efficiency in Multi-Unit Residential Buildings and with Section 6.2 Building Envelope of the ASHRAE Standard on Energy Conservation in Existing Buildings.
Maintain the fit, closure, and sealing of windows.
Routine maintenance needed to prevent energy waste and maintain comfort.
Issues and Concerns
The CMHC manual on Energy and Water Efficiency in Multi-Unit Residential Buildings can be found online at www.hwbinc.com/495-1003/introduction.html.
ASHRAE Standard ANSI/ASHRAE/IESNA 100-1995 – Energy Conservation in Existing Buildings is an approved standard of the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., the Illuminating Engineering Society of North America and the American National Standards Institute.
Analysis text here