If and when replacing inefficient, outdated or inefficient existing windows, it surely makes sense, given the ever rising costs of electricity and gas, to choose the most affordable thermally efficient replacement windows?
What are energy efficient windows?
Technological advances in the UK double glazing industry over the last decade have caused the first and second generations of replacement double glazing (which at the time was a massive improvement on single glazing) to be superceded by “thermally broken” energy saving efficient windows, that meant far better energy ratings were achieved.
Window Energy Ratings (or WER’s) were introduced by the British Government many years ago to help consumers know how thermally efficient any particular combination of frame, gaskets and glass sealed units were. Back on 1st October 2010, the Building Regulations changed so that from then on double glazing installers, suppliers and home owners had a legal responsibility if replacing windows, to replace them with either an independently tested “C” rated, “B” rated or “A” rated window, with until fairly recently, an “A” being the highest rating available, and “C” being the minimum standard permitted.
This legislation brought about a sea change in the double glazing industry, whereby it had to suddenly scrap any outdated non-thermally broken window products (which were unable to achieve the minimum “C” rating) for higher quality, better designed, more expensive, thermally broken products, be the window frames made out of aluminium, timber or UPVC (unplasticized polyvinyl chloride).
The resultant improved living environment and financial savings on energy bills for property owners has led to much of the UK housing stock being better insulated, so much so that home owners looking to sell their properties with older outdated double or single glazing are severely disadvantaged, or at the very least not able to achieve the sale price they had hoped for.
For double glazing manufacturers to achieve a decent window energy rating they need a frame that is thermally broken (i.e. where the outer pane and inner pane are separated, so that the cold on the outside cannot interfere with the warmth on the inside) and a high specification sealed unit with a warm edge spacer bar separating the inner and outer glass panes which is filled with an inert gas like Argon, which not only insulates, it helps with sound reduction too.
Recent technological advances now enable certain UPVC products to obtain even greater energy ratings than “A”. Some companies use triple glazing to achieve better than an “A” rating, whereas others have opted to improve their double glazed frames, making them more robust as well as more thermally efficient in the process.
Triple glazing sealed units costs more than double glazed sealed units simply because there are two warm edge spacer bars, rather than one, and three panes of glass rather than two. This means triple glazed units cost more to replace if they break down or crack than double glazed units, a factor worth noting if choosing between these two options.
Independent double glazing manufacturers and installers Hazlemere Window Company Ltd have been replacing windows in the UK for over 30 years. They have recently switched all their UPVC casement windows with side hung and top hung opening vents to A+ as standard. The outer window sash on the bespoke UPVC windows they supply and install now has six chambers increasing the thermal break between the inside and outside, as well as the robustness of the product. They also now offer a UPVC triple glazed window with a slimmer outer frame that has an A++ energy rating.
As it is now possible to have professionally fitted bespoke A+ energy rated double glazed windows installed for far less than A+ or A++ triple glazing, it makes better financial sense to invest in double glazed A+ windows. If the most thermally efficient windows on the planet are not well fitted, they won’t perform, so it is important to select an experienced installer you can trust to do a professional job.