Magnetite retrofit double glazing is specially manufactured to enhance the thermal properties of the building without reducing the visible light passing through the windows.
However, in order to buy good quality secondary windows and to fit them properly into the building structure, it is essential to gain some knowledge of window insulation systems.
Prior to retrofitting a secondary window system, it is essential to test their thermal insulation properties. The insulation testing standards used for windows are different from those used for general building material. Usually, the resistance of a material against heat loss is defined by its R-value. This value is considered as the benchmark in determining the insulation properties of building materials used to construct walls and roofs. However, it is not the perfect standard to judge the insulation properties of materials used in the construction of windows. This is due to the fact that unlike walls and roofs, windows have to allow solar light to pass through them. Thus, for windows, one should consider the U-value as the standard unit to test thermal characteristics. It measures the rate of transfer of heat through a solid material. Thus, while buying a window, look for a low U-value.
Other properties that help in the selection of energy-efficient secondary panel windows are:
- Resistance to Condensation: The condensation effect in a closed environment deters thermal control. This unit determines the property of a solid material to curb the condensation process. The higher the condensation resistance, the better the product.
- Air leakage/infiltration: It is hard to search for a secondary panel window product with no air leakage. Most products allow some amount of air to pass through. The market needs to be scanned for a product with minimum air leakage. Look for high quality seals and ensure the frames have a snug fit when installed. Use cavity closers to eliminate the possibility of air leakage after fitting windows.
- Visible transmittance: It is the property of a solid material to allow visible light to pass through.
- Solar heat gain coefficient: It defines the property of a product to block solar heat. The lower the coefficient, the higher is the ability to block heat. To exercise high control over the temperature inside the building, use a product with a low heat gain coefficient.
There are many products on the market and it is important to spend time choosing the right one for your budget and time frames.