Low E Glass is low emissivity glass and is commonly known as ‘Low-E’ glass. Emissivity is the rate at which heat leaves a building. Therefore, Low-E glass has a lower rate of heat-loss compared to glass that is not Low-E. In New Zealand there are two types of Low-E glass: soft coat and hard coat. Soft coated glass is extremely sensitive and can be clearer than clear glass. Due to its sensitivity, it needs to be created within an insulated glass unit. Hard coated glass does not need to be sold within an insulated glass unit, however there may be a haze accross the glass under certain light conditions.