High Performance Windows

High performance windows allow healthier indoor relative humidity levels to exist in the house with no condensation on the glass. Window glazing is the weakest link in a house envelope and in a frosty Manitoba winter, provides the coldest interior surface for condensation of moisture from indoor air. By choosing high performance windows, the interior glass surface is warmer and more resistant to condensation.

Health Canada recommends we keep the relative humidity (RH) in our homes between 30% and 50% RH. Lower performance windows will have a cooler interior glass surface temperature and allow condensation to begin at lower relative humidity levels. As wintertime window condensation is not desirable, the onset of condensation will cause homeowners to operate their ventilation system to reduce humidity in the house thus limit the option for higher, healthier relative humidity levels to exist.

The following three glazing options are most frequently installed in Manitoba homes. In general, the triple glazed, LowE coated, argon filled glazing with insulated spacers will allow the healthiest levels of relative humidity to exist within the home.

Good: Double glazed, LowE coated, argon gas filled with insulated spacers
Better: Triple glazed, clear, air filled with insulated spacers
Best: Triple glazed, LowE coated, argon gas filled with insulated spacers