What is 'A Rated' Glass?

Whether you are a domestic customer or trade customer you may have heard the term 'A Rated Glass' being used. There is however no such thing.

This term is becoming frequently used in the uPVC industry to describe a glass specification that will allow a window to achieve an 'A' rating. The actual glass specification they are referring to is:-

4mm Clear Float - 20mm Argon Gas Filled Spacer (90%) with Swiss V (or similar) Thermal Spacer Bar - 4mm Low-e (softcoat). This glass make-up achieves a centre pane U-value of 1.2 W/m2K.

In the majority of uPVC window systems this glass allows the window to achieve an Window Energy Rating of A, hence why it is being increasingly referred to as 'A Rated Glass'. Unfortunately, it does not always result in an overall A rating when Glazed into window systems and it is becoming more and more confusing for the end customer and trade alike.

The Window Energy Rating (WER) system applies only to windows, it also only applies to the window as a whole. Individual components cannot themselves have a window energy rating, i.e. the glass or frames.

This so called 'A Rated' glass specification we use as standard for the majority of our products. Using this so called ‘A’ Rated glass in one of our aluminium Smarts 47 windows (for example), achieves an overall 'C' Rating. Although this is still fully compliant with current building regulations, it may not be what the customer is expecting.

Find out more about WER’s here: http://www.duration.co.uk/Window-Energy-Ratings.asp

Internally or Externally Glazed

The glazing bead is the aluminium profile that secures the sealed units (or glass) into the aluminium window frame or opening vent. When inserting glass into a window system (often referred to as Glazing the window) the glazing bead and wedge gaskets are the last pieces of the window that you fix into place. Some windows are externally glazed (also known as “externally beaded”), while some are internally glazed (also known as “internally beaded”). Some window systems will use a mix of internally glazed and internally glazed sections within a single window.

There have been many arguments over the years as to whether internally glazed or externally glazed windows are better for security. With people using arguments such as: “If you glazed a window from the outside then you can de-glaze it from the outside. Therefore externally beaded windows cannot possibly be secure.” Along with counter arguments such as “Internally beaded PVC windows can simply have their glass units forced in”.

The majority of people in the industry once considered externally glazed windows to be less secure. This is simply due to the fact that internally glazed windows were developed, introduced and advertised as the more secure option. This is no longer the case due to the fact that the majority of externally glazed windows use modern technology, which means that the external glazing beads simply cannot be removed without removing the internal wedge gasket first.

The simple fact is that both internally beaded and externally beaded aluminium windows are secure and the industry standard tests are there to prove it. Therefore if a window system can pass these tests they are deemed to be secure. If a window can pass the British Standard 7950 and also the Police Preferred Secured by Design Standard, it is considered to be highly secure. So in the absence of any other even more stringent tests and standards, which should you choose, Internal or external glazed?

Key Points About Internally Beaded Windows:

• Can make installation far easier by allowing the installer to fit the frame from inside the building, without the need for scaffolding.
• Once considered to be more secure than externally beaded windows, however due to modern technology and the strength of aluminium, externally beaded aluminium windows are just as secure.

Key Points About Externally Beaded Windows:

• Externally beaded can provide a slimmer sight-line than internally beaded.
• From inside, the window may look neater as there are no bead lines.

Both external and internal beads on a single window:
Often you will find that a window system will mix internal and external beads on a single window. This is generally due to the fixed lites being externally glazed. Windows that do not open (otherwise known as fixed lites) are generally glazed from the outside directly into the window frame. Therefore, a window which is made up of an opening sash next to a fixed pane - would be internally beaded on the opening vents and externally beaded on the fixed pane. This gives the best looks and slimmest sight-lines. If you wish to have internally glazed through-out your windows you would normally have to opt for dummy sashes or a double beaded window frame. Dummy sashes provide equal sight-lines, as all the fixed lites are created by fixing opening vents into the outerframe, and are internally glazed.

Visit www.duration.co.uk for more information on glass and glazing.

Lower Your Energy Bills By Specifying Planitherm SGG

Saint-Gobain’s Planitherm glass is proven to be one of the most energy efficient glasses available in the UK.  Planitherm is a new generation energy saving window glass that uses an advanced ‘softcoat’ coating that helps to retain more of the internal warmth whilst capturing free energy from natural daylight (known as passive solar heat gain). This equates to lower energy bills compared to windows with standard glass. By specifying Planitherm in your windows you can cut your energy bills by as much as 28%*. All glass has a slight tint, however Planitherm products are almost completely clear and maximise the amount of natural light coming in.

Saint-Gobain is the largest supplier of high performance low-emissivity (or low-e) glass’s in Europe, and is one of Pilkington’s largest competitors here in the UK. Planitherm glass is not a new product; it has been available and manufactured in the UK since 2004. Duration Windows have been supplying Planitherm Total+ for many years. However since 2010 when Window Energy Ratings (WER’s) became part of the revised more stringent part L of the Building regulations, we have been supplying Planitherm glass as our standard double glazed sealed unit for the majority of our aluminium windows and doors.

This glass is designed specifically to to keep interiors more comfortable in the winter months and improve your home's energy efficiency. It is far easier to achieve a Window Energy Rating (WER) of ‘A’ when using Planitherm Glass, as it provides high solar gain, capturing free energy from natural daylight. Window Energy Ratings provide an outline or overall value for how energy efficient a window is and are an alternative to thermal efficiency (U-values) for compliance to the building regulations. WER’s are calculated by offsetting the heat loss through a window against the solar gain through the glass. Window energy ratings were introduced to the building regulations to try and help to reduce CO₂ emissions and protect the environment. The ratings range from A to G with a C-rating being the minimum rating required for compliance with current Building Regulations (Alternatively an overall U-value of 1.6 is required).
Find Out More About Window Energy Ratings.

The Planitherm range can be combined with many Saint-Gobain Glass products, providing a multitude of high performance of high performance, multi-functional glazing options, inculding:

• Self-cleaning and/or solar control glazing
• Acoustic insulation
• Safety and security
•  Obscured and/or decorative glazing

Planitherm products are the ideal low-e solution. Not only do SGG Planitherm products allow free heat and light from the sun to pass through the glass and warm your home, but they have a transparent metallic coating that reflects heat from radiators or fires back into the room, rather than allowing it to escape through the windows. This further contributes to the energy efficiency of your windows. The thermal insulation provided by low-E double glazing is three times more efficient than that of standard hard coat double glazing, such as Pilkington’s K glass. The coating is permanent and hermetically sealed within the glass unit so will last the lifetime of the window. Of course all old, uncoated, double glazing offers a limited level of heat retention. However, Building Regulations now state that an energy efficient window glass must be used in all replacement windows. A double glazed unit containing Planitherm is on average 40% more thermally efficient than standard non-coated double glazing.

Reasons why we use Planitherm Glass products:

• Free Solar Gain - Planitherm uses advanced coating technology to capture free energy from natural daylight, helping to heat your property.
• Thermal Insulation - The advanced coating reflects heat back into the room, meaning less energy is needed to heat the home to the desired temperature.
• Optimal Window Energy Rating - Planitherm combines with virtually any window frame to achieve a Window Energy Rating (WER) of C and an A rating is easier to achieve allowing for easy compliance to the Building Regulations.
• Haze & Tint Free Windows - Planitherm maximises the amount of natural light into the home, without the haze or tint effects associated with older double glazed windows.
• Eliminate Condensation - Planitherm helps to virtually eliminate internal condensation, reducing draughts and cold spots in and around the windows. 

For more information on the glass we use as standard, the glass we offer as upgrades and glass specification please visit our website at www.duration.co.uk

*Savings calculated using the GGF energy savings calculator based on upgrading from single glazing to A-rated double-glazed windows in an average gas heated detached house.

Aluminium Quad Trim

In our efforts to help our customers Duration Windows now offer a fully aluminium quad trim which can be colour matched and used with our extensive product range.

Visual representation of our new ali quad trim

This new quad trim promises to help you finish your install to a high, clean and professional standard. When you have completed installing one of Duration Windows aluminium products, mastic and seal around the edge between the product and wall then simply apply the aluminium quad trim using the tape attached. The sealant you applied will then adhere to the trim and provide a firm grip with a perfect visual finish guaranteed to satisfy your customers. With our trim being colour matched to the product this also eliminates having to use a silicone that does not coordinate (for example if the product is red) and provides a quick and perfect finish. 

For more information visit our website: http://www.duration.co.uk/Aluminium-Quad-Trim.asp

Or call the office: 01268 681612