What is Double glazing? and how does it work?
Across the UK double glazing has become a familiar sight in most homes. With the benefits of cutting utility bills and reducing noise pollution, double glazing is definitely a popular choice as energy bills continue to rise and many families make the move to noisier areas 1. But do you know what double glazing is and how it works? We’ve put together some great information outlining what double glazing is, what to look out for when buying double glazing and the main benefits.
What is double glazing?
Double glazing is created when two panes of glass are separated by a trapped layer of gas. This gas filled space between the panes of glass reduces heat transfer from the property. Generally, the two panes of glass will be produced in the same thickness, ranging from 3mm to 10mm. The panes of glass are separated by a spacer bar and all components are sealed in place to create an air tight single unit.
Where did double glazing develop from?
Double glazing is an evolution from double hung and storm windows, an older technology consisting of one pane of glass used to separate interior and exterior spaces. A window screen would be hung in summer to keep animals and insects out and a storm window would be added in winter to create a two layer separation between interior and exterior spaces. This double layer increased insulation in colder winter months.
Types of glazing
There are many different types of glass available for double glazing. One of the most important types is safety glass. Safety glass is mandatory in certain buildings including schools and specific areas such as roof windows to avoid injury 2. Safety glass must also be used in homes in areas regarded as critical. Doors and panels adjacent to doors within 1.5m from floor level as well as low level glazing such as windows that are within 0.8m from floor level must be glazed in safety glass 3. Laminated glass is stronger and more durable than standard glass due to its construction 4. A plastic interlay is sandwiched between two sheets of glass during manufacturing to produce a pane of glass that, if broken, would continue to stick to the plastic layer inside. This safety feature greatly reduces the chance of injury whilst adding extra security and soundproofing. Tempered glass is another form of safety glass which is 5 x stronger than standard glass 5. Tempered glass is subjected to intense heat during its manufacturing process followed by being rapidly cooled to create its strength. If broken, tempered glass would shatter into hundreds of tiny pieces, causing less injury. Due to its nature, tempered glass adds extra security and safety when used in specific areas.
How does double glazing help reduce heat loss?
The trapped layer of gas between the two panes of glass is key to the insulating properties of a double glazed window. Argon, the gas typically used, uses around 65% of the thermal conductivity of air, resulting in it being extremely inefficient at conducting heat. The spacer bar used in the construction of the window unit is also very important, ours for instance is 1000 times more thermally efficient than standard aluminium, contributing to the efficiency of the unit. This enables heat to be locked inside the home and helps to improve the properties overall energy efficiency.
The importance of choosing the right double glazing
To ensure you are getting the most energy efficient windows, there are a few areas you have to explore to keep your home warm and your energy bills down. All windows are labelled with an energy efficiency rating ranging from poor (G) to excellent (A). The regulating body that awards these ratings are the British Standards Institution (BSI) who have over 100 years of experience and setting the expectations of products and companies across the UK.
These energy ratings are awarded due to the overall properties of a window, not just the individual components so it’s important to look at all the factors including a few specific numbers which are represented by the letters U, G and L.
Thermal efficiency (U value) is another area to look at when buying double glazing. A windows U value is a way to measure the heat lost through the window. The lower the U value, the better the insulation provided.
Solar gain (G value) is another factor to consider. The G value rating is a scale between 0 and 1 which determines the windows solar gain. This indicates how much heat is let in by the window, allowing for a more natural form of heating your home.
The final factor to consider is Air Leakage (L value). Air leakage can occur if there is a weak point around the window frame. This weakness can come from the seals holding the glass in place. Most modern windows are fully airtight and should have an L value of zero.
What types of double glazing frames are available?
The most common type of window frame for double glazed windows is unplasticized polyvinyl chloride or uPVC. With white being the most popular, uPVC window and door frames are available in a variety of different colours and finishes which allows easy personalisation of the home. uPVC is also up to three times cheaper than traditional wooden frames 6, it also has the added benefits of being recyclable, durable and energy efficient. Alternative options include wooden and aluminium frames. Wooden frames are more expensive and need more maintenance which is why more people opt for the cheaper, long-lasting uPVC frames.
Further benefits of double glazing
Keeping homes warm is one of the main benefits of double glazing. 44% of people surveyed by Which 7 upgraded to double glazing to keep their home warm and 40% to reduce their energy bills. But there are some other benefits to having two panes of glass rather than one. Noise insulation is another benefit of double glazing. The second pane of glass acts as a noise barrier, keeping the property suitably insulated from outside noise. Double glazing also heightens security 8 as double glazed glass is more difficult to break than single glazed.
When choosing double glazing we appreciate there is a lot of information to take in. To ensure you get the right product for your home we would definitely encourage getting advice from an expert in home improvements – we have years of experience installing every type of double glazing possible to hundred of thousands of customers across the country. Give us a call on 08009870024 to speak with a member of our team, or get a free quote.1 cherwellwindows.co.uk 2 double-glazing-info.com 3 leadbitterglass.co.uk 4,5 sterlingbuild.co.uk 6,7 which.co.uk 8 homelogic.co.uk