HAVAN eLearn

Condensation/frost on windows/doors is a nuisance for occupants, specially in buildings that experience cold winters. The industry practice of determining the condensation resistance of windows/doors is focused on the glazing assembly's thermal performance (frame, perimeter of the Insulated Glazing Unit (IGU), and the central part of the IGU), indoor relative humidity levels, and the temperature difference between inside and outside of a building. While this approach can provide a reasonable indication of the performance comparison of various windows and doors, it falls short in providing the big picture understanding of other influencing factors, and how they can impact the in- service moisture management of a given window/door as far as the control of condensation/frost is concerned.

Based on a recently completed (February 2022) three-story house in British Columbia, Canada, this session demonstrates how the combination of air leakage, interior blind configurations, heating systems, and assembly/installation methods greatly compromised the in-service condensation performance of otherwise extremely thermally efficient sliding doors (triple-glazed, thermally broken aluminum frame). More importantly, it will be shown how the condensation/frost on the sliding doors was manifested differently in each level of the building, leading to an intuitive grasp of the topic. The findings and analysis of this insightful case study are supported by physics, smoke test, whole-house air tightness test, infrared thermal imaging, and thermal simulation.

Learning Objectives

By the end of this session, the participants will gain practical insights towards:

• Taking a holistic approach towards assessing the in-service condensation resistance of windows and doors, in particular the operable ones.
• Practical steps to greatly reduce the likelihood of similar occurrences.
• The importance of on-site water and air testing for site-assembled
  doors/windows.
• The need for a close review of the NAFS reports supplied by the door/window manufacturers. 

Target Audience
The content of this session will be suitable for builders, architects, designers, building inspectors, energy advisors, window manufacturers, carpenters, and whoever interested in “high performance” building practices.