Are Your Windows Crying or Trying to Tell You Something ?

Are Your Windows Crying ?

The other morning I noticed my neighbour’s windows running with condensation due to the very low exterior overnight temperature. I then noticed one of our own dripping condensation. It made me start to really think…
This is a BIG concern at this time of year and over the fall /winter, as the moisture running-off can cause interior damage and MOLD.


Condensation problems can be a result of many variables. Thermal conductivity of surrounding building construction, interior /exterior trim, humidification- control and the method of heat distribution on the interior will impact overall window performance and ability to remain dry. Conditions which may affect interior surface temperatures to allow condensation include (but are not necessarily limited to) the following:
• Type of wall construction and material(s) used therein
• For cavity walls, location of thermal barrier in the product with respect to the wall cavity
• Closed drapes and /or shades
• Depth of reveal (recess at stool, jambs and head)
• Positive exterior wind pressure or negative pressure within the dwelling which may increase infiltration of cold air
o Height above grade
o Location of surrounding buildings and type of surrounding terrain
o Wind velocity
• Solar radiation and orientation
• Water vapor pressure and temperature indoors
• Water vapor pressure and temperature outdoors
• Rate and amount of water vapor released to interior
So – how to control this wide-spread problem ?
Open-up window coverings to allow warm and drying air-movement over those cold windows.
Keep interior doors open during the day.
Consider pruning-back over-grown trees outside if they are shading the windows excessively.
Control indoor moisture with quality exhaust fans and a de-humistat control in each and every living space.
Don’t hang laundry to dry indoors.

Note – the control is set to “off”; we’ve added the blue arrow to show the proper setting – ideally always below 50%

By managing interior moisture in the air and allowing heat to “wash” over interior windows, you can lessen sweating windows and the damaging effects of condensation running off.

This Tip brought to you by your Vancouver Home Inspector


About Glenn Duxbury

Duxbury & Associates Building Inspection and Consulting Ltd. has received the 2004 Douglas College Entrepreneur of the Year Award in the ‘Consulting’ category for persistence and pursuit of excellent service delivery to clients by providing very thorough and professional Inspection Reports and dedication to those involved in buying / selling / building / renovating and maintaining uncompromised customer focus.