Climate and Low E Glass Coating

By Robert Berge

Low e glass coating involves coating glass using one of two methods, or types of coats, that result in a virtually transparent coat of metal that effectively decreases the emissivity of the glass it is applied to. The two types of low e glass coating are hard and soft coating respectively. Choosing the one that is right for your home is important.

Hard coating in low e glass is the more durable of the two in handling, but has a higher ‘sun gain’ than soft coating. This means that while it still reduces heat loss significantly, it allows more solar heat to pass through it than a soft coat. In particular, this type of low e glass coating is best suited to windows in colder climates – interior heat stays in; exterior (solar) heat passes through with greater ease making it warmer inside.

A soft low e glass coating, also known as a ‘sputtered’ coating is typically more expensive since it can have a moderate to low solar gain while also insulating heat inside. A soft low e glass coating with moderate solar gain would be more desirable in climates that have both warm and cold seasons, while a soft low e glass coating with a low solar gain would find its best match in places that are typically warm all year round and cool interiors are a priority. Again, this is because the soft low e glass coating will keep sun heat out and maintain a cool interior temperature.

Simply put, the climate you live in will determine which type of low e glass coating is best for your home.