Understanding Low-emissivity (Low-E) glass

04.07.2021

Window glass is by nature highly thermally emissive and it lets heat pass through it in both directions. But in extremes of summer and winter, that’s not such a prefered situation. On the hot summer days,  it is preferred that windows reflect back the sun’s heat automatically. Likewise, on the winter days, it would be great if the windows of your home help to stop all that expensive heat from escaping. 

Low-emissivity (low-e) glass is a type of energy-efficient glass designed to prevent heat escaping out through your windows to the cold outdoors. Low-emmisivity (Low-E) glass has a special coating applied to one of the glass faces. 

Low-E provide better thermal performance (U-value)

Low E applied to windows helps block infrared light from penetrating the glass from the outside. In addition, Low E helps keep in your heating/cooling energy. Bottom line: they are much more energy-efficient, helping you save on heating and cooling costs and costs associated with running your heating/cooling systems.

Low-E reduce destructive UV rays

Exposure to direct sunlight can cause many coloured or painted materials to fade. Damage due to fading is caused by mostly ultraviolet (UV) light. The Low-e coatings help reduce UV light. Blocking UV rays save your carpets, furniture, drapes, and floors from fading and sun damage.

How does Low-e work?

 

Types of Low-E coating

Solar Control Low-E: Blocks solar radiation to reduce cooling costs. Higher-performing glasses
are applied or produced by a magnetron sputtered vacuum deposition (or MSVD) soft coat process.

Passive Low-E: Transmits solar radiation for passive heating applications. Reduces heating costs. Applied on products by a pyrolytic or MSVD soft coat process.

Low-e coating can be either a ‘hard coat’ or ‘soft coat’ depending on the actual coating process used.