Sash Windows for the Twenty First Century

When looking for a company to undertake your sash window replacement you might as well choose the best. However what constitutes the best sash window replacement company?

• The company must be reliable
• Skilled in removal and replacement
• Affordability
• Top quality double glazing

It is the latter I will be dealing with in this article.

What constitutes a top quality double glazing for a replacement sash window? Below is a list of the most important aspects of a modern sash window.

• Good window energy ratings (Energy Efficient Glass) Sash window
• Translucent glass (no dusty effect, no tint) sash window
• Condensation free sash window
• Good frame design for a sash window
• Ease of opening and closing of sash window
• Security of overall sash window

WER or Window Energy Ratings have been in existence since 2004. These ratings were established by the British Fenestration Ratings Council 'BFRC' in an attempt to help standardize and quantify the energy efficiency, or otherwise of products. This remains a highly useful benchmark. We are all familiar with the colour coding system applied to domestic appliances the same coding system is also used for assessing the efficiency of sash window replacement units. The thermal rating for a window unit is arrived at by the following formula:

WERS= Solar Gains - (Thermal Losses + Air Leakage).

The resulting value (Energy Index) is then placed into a band on an A-G scale consistent the colour banding system used for domestic appliances. 'A', being the most energy efficient, descending in increments to the lowest band 'G', the least energy efficient with a energy conservation value 'WERS' of less than -70.

Recent building regulations for England, Wales and Northern Ireland include WERs, Window Energy Ratings. The minimum level for replacement sash window replacement for the domestic setting is band E. As we become ever more environmentally conscious and the choice of energy saving products improves, you should now no longer consider any product that has a WER rating lower the C. A C rating or above qualifies a product to carry the Energy Saving Recommendation logo. I strongly recommend that any replacement sash window you have installed should bear this logo, and whether this 'energy saving recommendation logo' is on their products.

In order to get this grade the replacement window industry has had to put in a large amount of investment in research and development. A product has been developed that employees three important components. The component in this group of three is the glass panel with E coating. This E coating or 'low emissivity layer' is comprised of a series of metallic oxide layer. A low-emissivity coating is added to the inside of the pane facing the interior of the house. This coating allows natural light 'free passive solar heat' to enter the pane but, reflects heat energy from the interior back into the interior. This development alone has resulted in replacement sash windows that are 3 times more thermally efficient than standard double glazed replacement sash windows.