Low Emissivity Glass

Be energy efficient with your glass – choose low emissivity glass.

Just like technology, glass is moving on too. Developments and industry research give us new opportunities for glass and glazing in our homes. We can only ever want good, robust quality but in these changing times we also expect improved energy efficiency and thermal performance too.

What is low emissivity glass?

Before we go on, let’s call it by its abbreviated name of Low-E glass, it’s far easier! It’s basically a coating on glass that reduces the amount of ultraviolet and infrared light that passes through it. However, this film does not visibly reduce the amount of light that passes through the glass. It’s basically working harder but not affecting our day to day use. The coating is transparent and thin, it doesn’t change the appearance of glass but it does reflect light and solar energy.

Would Low-E glass be good for my house?

Are you familiar with the process of emissivity? It’s when heat is absorbed by glass and then radiated out. This process allows for the transfer of heat from inside your house to outside, meaning that the temperature indoors will be lowered. Don’t worry though, it works the other way too, so heat from outside passes through and heats the inside of your house.

Glass that has low emissivity, or Low-E, has a slower transfer rate so the process of insulation that glass offers is improved. So, in the winter your house will be warmer as the heat inside your house will be reflected back inside. In the summer it will be cooler because the outside heat is reflected and won’t enter your home.

Low-E glass will give your house a more consistent temperature all year round. Your carpets, furniture and belongings won’t be affected by sunlight so they won’t be at risk of fading or becoming damaged. Don’t worry though, you shouldn’t notice a difference in daylight, your house will still be as light and bright as it always was.

How is Low-E glass made?

There are two different types of Low-E coatings. They are sputtered and pyrolytic.

The sputtered coating is made from metal oxides including silver and are multi-layered. They are invisible to the naked eye as they are so very thin but this doesn’t stop them from offering great protection against heat entering your house. This coating is more likely to be used inside sealed double glazing as it is less durable. It will keep it from becoming damaged.

The pyrolytic coating is baked into place as it is bonded to the glass using a metallic oxide. It is thicker than the sputtered coating option but still thin enough to keep the glass clear. Much more durable than sputtered coatings, they can be exposed and cleaned in the normal way and can be used on single glazed units even though they are exposed to air!

Low-E glass has four potential surfaces that the coating can be applied to. Low-E coatings appear on the inside and outside pane of most double glazing units. This is to make sure it’s cool in the summer but warm in the winter – this is a requirement for UK homes. A coating of pyrolytic is usually used on homes which use heating indoors. To reflect the sunlight out of the home a sputtered coating will be used. It isn’t unusual, for some properties to have both coatings.

Utilising Low-E glass for your home glazing needs is a superior choice when insulation is so important in the UK. With such a degree in difference between the winter and summer months it makes it the perfect choice.