Energy Efficient Glass

Energy Efficient Glass

The energy rating label runs from A-G with band E as the lowest level permitted for replacement windows. This generally requires a Low-E sealed unit.

Domestic extensions have to be band D or higher. This generally requires a Low-E Argon filled or warm edge spacer (Super Spacer or Enviro-TXN) sealed unit. New build can be up to band G, but only if the whole house meets other energy saving targets.

The Energy Saving Trust will allow the use of their logo for windows that achieve band C or higher. This generally requires a Low-E, Warm edge spacer and Argon filled as a minimum standard.


Low – E glass is a vital component of energy efficient windows. It has a virtually invisible surface coating which operates as follows:-

• It allows heat from the winter sun to enter the home through the glazing.

• This solar energy works with domestic heating systems to warm up rooms, which then gives off long wavelength heat radiation.

• A large proportion of that wavelength heat would normally vanish back through windows made of ordinary glass. However, the Low –E coating reflects that heat back into the room, i.e. the coating traps the heat in the home, therefore making it a lot warmer during the winter.

Low – E glass not only meets the new Part L of Building Regulations it is virtually essential to enable you to achieve the new targets.

Guardian Low-E

This is a hard coat glass, neutral in both reflection and transmission, providing crystal clear vision with no unsightly haze.

High light and solar heat transmittance – allowing the best use of natural lighting and beneficial solar heat gain. Uniform with no unsightly banding effects within the glass panel. Excellent thermal insulation – U values down to 1.4 W/m2K when gas filled, allowing energy saving requirements to be easily achieved and reducing heating costs.

As well as standard glass, laminated and tempered glass are also available to provide safety and security where needed.

Pilkington Energikare

Pilkington energiKare is different from standard double glazing.

It reduces the amount of heat lost through the windows and it also allows more heat (energy) from the sun in through the window, known as solar gain.

Pilkington energiKare is made up of two special types of glass, Pilkington K Glass, low emissivity glass which stops heat escaping and Pilkington Optiwhite, a special ‘extra clear’ glass which allows more solar heat in through the windows. The use of argon gas or air filling with warm edge spacer further improves the thermal performance, and your home benefits by feeling warmer without the need to turn up the heating.

The Benefits of Pilkington energiKare:

  • Improves the energy efficiency of your home.
  • Reduces the amount of energy you use.
  • Saves you money on your heating bills.
  • Is more effective than single or standard double glazing.
  • Is the only product that offers you the reassurance of Pilkington quality and enables  windows to be eligible to apply as part of Energy Saving Recommended scheme.
  • Pilkington energiKare is suitable for use in PVCU, timber and aluminium windows.
  • Manufactured to the highest British and European quality standards.