Double Glazing

We offer a wide range of options for all our products. We comply with all aspects of current legislation and in particular the most recent building regulations with regard to energy efficiency.

Energy Efficiency explained

There is much confusion and uncertainty about the current building regulation legislation in relation to energy efficiency in replacement windows. The law now requires all replacement windows to meet the new energy efficiency standards in one of 3 ways:

  1. To have a whole window ‘U’ value of 1.6 W/m2/K or lower.
  2. To have a minimum window energy rating (WER) of ‘C’.
  3. To use sealed units with a ‘U’ value of better than1.2 W/m2/K with argon gas fill and warn edge spacer bars.

There is no energy rating scheme for doors at present but all doors where more than 50% of the total area is glazed must have a 'u' value of 1.8 W/m2/K or lower.

The calculation for energy ratings also takes into account the heat loss (‘u’ value) and solar gain (g value) of the sealed unit. It is possible to offer a high ‘U’ value with a high solar gain value and still meet the requirements of a ‘C’ rated window. The lower the ‘U’ value, the lower the heat loss.

NB. It is important to realise that window energy ratings and ‘U’ values refer only to the energy efficiency of a window and in no way represent the quality of the product itself, i.e. it is very possible to have a ‘C’ or 1.6 W/m2/K rated window manufactured in a good quality product and an ‘A’ rated or 1.4 W/m2/K rated window manufactured in a cheap, inferior product.

Our preferred method of compliance is to manufacture only in top quality products and offer the whole range of energy efficiency. We usually use a ‘whole window calculation method’ to prove the ‘U’ value and give a certificate to verify this. Our documentation also gives an equivalent value on the ‘A’ to ‘C’ scale. We are also able to provide windows with a WER rating.

In our opinion, it is better to have a low ‘u’ value sealed unit (less heat loss) because in the winter months it is more important not to lose heat and less likely that there will be a significant solar gain benefit, while in summer, when there will be a high solar gain, windows are usually opened to cool the house.

Our range includes:

  • Low emissivity glass
  • Toughened or laminated safety glass
  • Self cleaning glass
  • Solar control glass
  • Acoustic glass
  • Georgian style glazing (astragal - surface mounted - or internal)
  • Leaded-lites (rectangular or diamond)
  • Patterned glass
  • Stained glass
  • Argon or Krypton gas fill
  • Georgian wired glass (polished or cast)
  • Fire safety glass
  • Multi-wall polycarbonate (clear, bronze, opal, ‘Venetian’ solar control)

All glass units are available with standard or energy efficient warm edge spacer bars.