Some companies in the stained glass industry say that it is not necessary to have an external storm system.

It is a well-known fact that the windows of a building are where the greatest energy loss is experienced.Leaded stained glass windows With the ever-increasing costs in energy, the Department of Energy has targeted windows, in the building environment, as the area needing improvement.

Leaded stained glass windows are many small pieces of glass held together by lead caming. Set alone a leaded stained glass panel is less energy efficient or weather proof than a single pane of plate glass. The common saying is that "a leaded stained glass window is like a screen door".

The churches I visit, that do not have an external storm system over their windows, usually comment that:

• There is a steady breeze coming through the windows.
• Candles won't stay lit. - Nobody sits at the ends of the pews.
• The organist and choir get cold.

Another more serious problem is rain seeping through the windows, at the lead came, and running down the interior of the church. With stone and metal frames, water may enter through areas where there is deteriorated glazing or mortar. Water infiltration will damage interior plaster walls and wood moldings and will accelerate the deterioration of wood, metal, and stone frames.

Cathedral Crafts answer to all of these problems is to install an external permanent protective storm system consisting of General Electric Lexan XL, an advanced glazing material, set in an aluminum track frame, and sealed weather tight with General Electric Silpruf silicone sealant. This storm system is set at the original rough opening of the window as to cover the window frame as well as the stained glass window. This setting protects the frame from deterioration and allows for a larger thermal barrier (area between the stained glass window and the external storm system).

Here are some answers to some commonly asked questions:

Q: Will the Lexan XL yellow or discolor?

A: General Electric has been manufacturing Lexan XL for 16 years. Cathedral Crafts has been installing this product since that time, and there have been only a few isolated reports from some of the earlier installations. By isolated I mean that at one location there maybe one or two pieces that have discolored slightly. General Electric guarantees its product for ten years and Cathedral Crafts guarantees its installation for ten years. Any reported problem is dealt with expeditiously.

Q: Will the storm system be vented to reduce excessive heat build up?

A: Yes, although Cathedral Crafts does not believe that drilling holes in the storm system and installing louvered plugs is the way to do it. It is more proper for the thermal barrier to breathe to the interior of the church. We have already determined that leaded stained glass windows are not airtight and there is airflow though the wood frames also. If more ventilation is needed the necessary actions will be taken to avoid future problems.

Q: Is condensation a problem?

A: If there is proper internal ventilation there will be no condensation. Smaller windows are sometimes sealed more airtight and it is necessary to make drain holes in the aluminum frame to allow any condensation to escape. The wood sills are wrapped with aluminum coilstock to prevent any deterioration.

Lexan VS Glass

Companies that promote the installation of glass over Lexan XL for storm system generally use the argument that the Lexan XL will discolor. Cathedral Crafts believes that there is a greater chance that a piece of glass will break than a piece of Lexan XL will discolor, increasing future maintenance costs. Cathedral Crafts has also restored many stained glass windows, supposedly protected by glass storm systems, that have been damaged by tornado winds, hail storms, and vandalism. In every case the restored windows are now being protected by a permanent protective Lexan XL storm system.

Protecting the history of the church in its stained glass windows, rendering them maintenance free, and the practical energy savings are the main reasons for having Cathedral Crafts install a permanent protective Lexan XL storm system.

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