b'BACK TO BASICS A similar phenomenon is shown in Figure 12, where a vehicle parked overnight (and therefore obviously at ambient tempera-ture) shows condensation on the rear side window. From the reflection in the car windows, it is apparent that this side of the vehicle is exposed to a clear sky, which at night would produce the temperature depression that results in condensation. Note that, as the lower part of the windows curve down to face hori-zontal, the radiant exchange is more with the adjacent features and less with the sky, and less condensation shows up. With the increased focus on high-performance windows, you FIGURE 9: SILL COVER REMOVED, EXPOSES BACK OF SILL PAN can expect to see more of this type of condensation, and its a problem because it interferes with the viewto correct the problem, residents would have to go outside to wipe off the water, which is not always possible in high-rise residences. The solution to the problem can be seen in Figure 11you can see that there is no condensate on the upper portions of the glass, because night-time radiation to the sky is blocked by the overhanging eaves. Thus, overhangs or canopies can be used to reduce exterior condensation. An insect screen would have a similar effect, but this might be seen as interfering with the view.Window condensation happens. You may need to brush up on psychrometrics to diagnose the causes and recommend solutions, keeping in mind that the problem may not always be the windows themselves. You may then have a challenge explaining to the owners that the problem is actually how they are operating their exhaust fans, or that the problem with window condensation is FIGURE 10: BACK OF SILL PAN CUT OFF, SHIMS BEING MOVED related to kinked flexible ducts in a corner of the attic. That kind of holistic thinking is why we talk about building sciences, not just the building envelope.Toro Aluminum is a leading window wall and door supplier for high-rise condominiums, office buildings and hotels across Canada, the UnitedFIGURE 11: EXTERIOR CONDENSATION ON WINDOWS AND DOOR States and Mexico.UNITIZED CURTAIN WALLUNITIZED WINDOW WALLRAILINGS(866) 320-7307 | www.toroaluminum.comFIGURE 12: EXTERIOR CONDENSATION, NON-RESIDENTIAL20 BCBEC ELEMENTSA BCBEC PUBLICATION'