Why fitting new thermally broken double glazing to homes is a no brainer

Why fitting new thermally broken double glazing to homes is a no brainer

With energy prices at an all-time high and set to constantly rise ever higher, even one bed flat owners in the UK will benefit from having thermally broken “A+” rated or even “A**” energy efficient windows installed, especially when done in conjunction with draught proof, thermally efficient doors.

The vast majority of 1st and 2nd generation replacement double glazed windows were not thermally broken, so although a big improvement at the time, there are now aluminium and UPVC double glazing products available that not only provide a thermal break between the inner and outer frames, but also a dramatic improvement in energy saving compared to non-thermally broken products.  Consequently the larger a property, the greater the energy savings are going to be by having double glazing fitted, given it costs exponentially more to heat a premises the larger it gets.

Nowadays, thanks to technological advances and better design, there is a range of genuinely “A+” rated fenestration products available that are far superior to old windows and doors. For example, many homes in the past were fitted years ago with silver anodised aluminium double glazing within hardwood frames, with some home owners subsequently reporting occasional condensation on the inside frames on cold winter mornings. This condensation can be caused by various factors, firstly often insufficient ventilation within a room and secondly by the fact the product does not have a “thermal break”. Nowadays most high quality aluminium windows have a polyamide thermal break between the inner and outer frames which prevents the external cold surface of the outer window pane meeting the warm surface of the inner window pane, hence why today you can purchase “A” rated thermally broken aluminium double glazing as well as “A+” rated UPVC double glazing.

Whatever material double glazing frames are made of, the other crucial element of an energy efficient double glazing system is the glass sealed units. Most energy saving windows need a sealed unit with a centre-pane U-Value (a measure of thermal efficiency) of about 1.2 W/m2K to enable it to achieve an overall energy rating of “A+” when combined with the gaskets and aluminium or UPVC window frames.

Consequently the glass sealed unit specification is critical to the overall energy performance of double glazed windows. In between the two panes of glass (usually each 4mm thick) is an air gap of 16mm to 20mm. These two panes are separated by a “Warm-Edge” spacer bar to prevent thermal transference. This vacuum gap is then usually filled with 90% Argon or Krypton which basically helps retain warmth generated by the property’s heating system on cold winter days and helps keep out excess heat on hot summer days.

Hazlemere Window Company Ltd use a high specification of glass as standard in their sealed units and standard. On the external pane they use a very clear low iron glass with no “green” colouring, which allows more light and heat into a room (Solar Gain). This clear glass reduces the amount of artificial light required, thereby saving on electricity bills. On the internal pane they use a high performance low emissivity softcoat glass, a product which has a special coating on the internal side of the inside pane, which helps retains heat that has been generated by the central heating system or by solar gain, or both!

The softcoat glass used has a highly neutral appearance with optimal solar heat gain, thermal insulation and light transmission to provide the highest Window Energy Rating (WER) performance. The WER scheme is the UK Government backed method of assessing and ranking the energy efficiency of a complete window. Taking into account its U-Value, solar gain and air infiltration, the scheme allows straight forward comparison of the energy efficiency of different windows, with an “A++” rating being the best (triple glazed UPVC) and “C” rating being the minimum replacement windows must achieve.

This new minimum standard of energy efficiency came in on 1st October 2010 when revised Building Regulations make it a requirement that any property owner replacing one or more windows must comply with. The reality is that “C” rated windows are exceptionally thermally efficient when compared to first generation double glazing and single glazed windows, and provide a level of thermal efficiency that most UK house holders would give their right arm for, given the amount of energy they will save the property owners.

Those with properties that have thermally inefficient windows and doors who want to future proof their homes against rising energy bills therefore need to replace their old draughty windows with modern energy rated double glazing. Given the additional costs of heating larger homes fitting technologically advanced replacement double glazing is an absolute no brainer.