Condensation on the surface of the sealed unit inside the house is caused by ambient humidity, which must be controlled compared to the outside temperature. At the beginning of fall, when the heating system does not function regularly, the water content of the house can vary around 60%, thus involving a problem of condensation on the interior suface of the glass. On the other hand, in winter, the ideal water content for the occupants is between 30% and 50%.  A rate lower than 15%, according to the medical authorities, irritates the respiratory tracts. When the outside temperature is under -10° C, the water content recommended is 30%.

The following charter is a good indication of the relative humidity recommended:

Exterior temperature °C	Relative humidity with an interior temperature of 20°C (68°F)
-30° or less	No more than 15%
-30° to -24°	No more than 20%
-24° to -18°	No more than 25%
-18° to -12°	No more than 30%
-12° to -6°	No more than 35%
-6° to 0°	No more than 40%

Source: CMHC: Canada Mortgage and Housing Corporation.  www.cmhc-schl.gc.ca

Condensation on the exterior side of a sealed unit is a phenomenon that happens on high performance glass as Super HP® glass.
Exterior condensation usually happens when these parameters are met:

• High relative humidity level (ex.: ext. temperature near the dew point)

• High performance glass

• Early in the morning

• Direct exposure to a clear sky toward North, East or South.

• Wind absence

If the surrounding temperature is slightly over the dew point and the glass temperature is slightly below: Condensation will occur on the glass.

This phenomenon happens because of high performance systems limiting the inside heat from escaping to the outside.

Because all the conditions mentioned here happens quite rarely, it's relatively seldom that we can observe it, even on high performance windows.
When you come across it, you can be assured that a superior window system has been installed.

The extruded aluminium screen comes with 2 springs (black) in a rail on each vertical side; moving these toward the middle will make the screen looser. Conversely, moving the spring towards the corners will make it tighter.

Any claim must be directed toward the Fenplast dealer who sold you the windows. It must be joined with a warranty certificate and the original bill or contract.
In case the dealer who sold you the goods is no longer in business, you can reach us directly.
Please, make sure to supply us our production number, the delivery date and the name of the dealer, all this information is written on the warranty certificate (if before 2004).

You can either reach us by e-mail at the service@fenplast.com or by phone at 1-888-336-7527 extension 405. If you have any document to fax us, you can send it to 514-990-0032, and please indicate clearly on your cover page that it's for the service department.