What is "low e" glass and why should you consider it when you have a double glazing project?
While there are many different types of glass product and several different categories, "low emissivity" glass provides the most efficient thermal insulation possible. In the industry, these windows have a very low "U" value, which determines their comparative ability to transfer heat. Windows that are composed of glass with a low U-value will be the more efficient of all products, when it comes to heat loss.
How is Low E Glass Made?
There are two different types of manufacturing process involved in creating this efficient, thermal insulation glass. The first uses a process known as "sputtering," where thin films of a specific material are deposited onto the glass surface. This is a highly involved operation which takes place in a vacuum. Alternatively, paralytic coatings can be burnt onto the glass surface in the factory of origin, while the "host" glass is still hot and malleable.
What Types of Low E Glass are Ideal for Double Glazing?
There are two different types of "low E" glass available for double glazing products. The first is classified as high transmission, allowing daylight to pass readily into the property, while reducing the volume of infrared, long wavelength heat that can escape the other way. Alternatively, low transmission options have a coating that inhibits the total amount of solar heat gain, while allowing high levels of light to be transmitted.
Indeed, window units composed of low e glass were shown to reduce the amount of heat by 25%, compared to traditional products. In double glazed windows the performance improvement was even greater, at 40%. For more energy savings a window installer can include special spacer bars, known as "thermal break" options. These bars inhibit heat loss around the peripheries of the window, by as much as 65%.
There are a number of different combinations to consider before selecting double glazing for your particular situation. For optimal performance, low E insulation glass (available from companies like Enviro Vision UPVC) can be combined with products that are easy to clean, insulated from sound, designed to protect against UV rays, or act as a security barrier. As an example, a conservatory could be configured to include self-cleaning glass, as well as glass designed for solar protection. This would offer the end user the ability to avoid excessive heat accumulation in the summer months, while working with with a product that is easy to clean.