The War Of The WER’s?

Over the last four years there have been many articles written about Window Energy Ratings. Some singing the praises of the new simplified system, with which consumers and specifiers can easily compare competing products. They talk about how using a simple and easy to understand ranking and labelling system makes buying new windows far less daunting for the average homeowner. They also talk about how energy efficient windows will save you money on your household bills and can even put heat back into your home by means of solar gain.

On the flip side other parties have written about the failings and limitations of the Window Energy Ratings and believe that these new ratings are simply made up rubbish aimed at trapping the general public into believing that one window is vastly superior to any another just because of its energy rating. They state that Window Energy Ratings provide no true measurement for energy performance, and urging people not to be duped by the British Fenestration Rating Council, and their WER Scheme. They call the WER system just another double glazing sales trick and a way to increase competition and profit margin within the glass fabrication industry. One blog even referred to WER’s as ‘The Emperors New Cloths’.

Many people are concerned that the potential energy savings, and reduction in CO2 emissions may not be fully realised due to the ambiguous nature of these WER calculations, but many also believe that overall they are a step in the right direct and stop so called ‘cowboy double glazing’ firms from specifying outdated products with compliant double glazed sealed units. 

The facts about Window Energy Ratings

In October 2010 the WER rating scheme was introduced as a new method by, which windows could comply with the Building Regulations. It was made mandatory for all companies within the window industry to test and rate their products, if they wanted to be a part of it. Since it was in many cases easier to achieve the minimum WER ‘C’ than the minimum U value of 1.6, now required by the Building Regulations, many companies did exactly this. The ratings are much the same as white goods, used to prove the energy efficiency of a product. Windows are rated A to G, and contrary to popular opinion a D - G rated window could still comply to the building regulations so long as it had a U value of 1.6 w/m²k or lower. Window Energy Ratings are an alternative method of compliancy, to the humble U value, but how can a window be energy efficient if it doesn’t consume energy in the form of gas or electricity? Its all very confusing isn’t it.

Even now years later many people still do not understand Window Energy Ratings, what they are and confuse them with thermal efficiency (U values) and even believe that they provide a measure of manufacture quality or security. Some people even talk about A rated glass, which is simply a term used in the industry to describe a sealed unit with a certain specification. This specification will in most cases (but not all cases) result in an overall Window Energy Rating of ‘A’, so it kind of makes sense. But glass cannot itself have a Window Energy Rating and this sort of terminology or industry slag, muddies the water and further increases ignorance and confusion.

But what purpose do Window Energy Ratings serve, if any? What are they, and how are they calculated?

If you are confused about Window Energy Ratings, We Can Help?

We have devoted an entire section of our website, in an attempt to clarify and answer exactly this. If you wish to get to the bottom of the Window Energy Rating scheme then it’s a very good and unbiased view to Window Energy Ratings. It will provide you with just the facts; without any speculation into Government Agenda and the glass fabrication industry. Nor does it try to use WER’s as a tool to try and sell you new energy efficient windows. We believe that it is certainly worth reading before you decide to buy yourself some new windows.

Read More »

Our Download Our Window Energy Rating Guide » 

Composite Aluminium / Timber Windows

Creating sustainable, energy efficient buildings is the cornerstone of most architectural designs. That is why Duration Windows is now offering a new range of Duratherm composite windows. They combine the advantages, long life and low maintenance of aluminium externally - with all the warmth and natural beauty of timber internally.

These composite windows are environmentally friendly and fully compliant with BS ENISO 9001, BS EN ISO 14001 and OHSAS 18001 standards. Designed and manufactured within the UK, they are made from 100% PEFC UK accredited timber and 100% recyclable aluminium. That’s wood accredited by The Program for the Endorsement of Forest Certification. They are thermally efficient and exceed all current standards, making them an ideal solution for both new-build and refurbishment projects. It’s the best of both worlds.

Internally, this Hybrid system features either natural or painted timber. There is a choice between either natural spruce or traditional oak woods, or spruce timber painted in a large range of water based paints. Externally, it comes in a choice of polyester powder painted aluminium - virtually any RAL colour in either a gloss, satin or matt finish. A silver anodised external finish is also available. 

There is a wide selection of hardware options, including advanced security options, performance tested to BS7950.  These windows are highly thermally efficient, achieving fantastic U values inline with the current building regulations and excellent weather ratings in accordance with the requirements of British Standards. 

The Duratherm range is renowned for combining strong sustainability benefits with proven, effective design innovations.

Find Out More at: http://www.duration.co.uk/Aluminium-And-Wood-Hybrid-Windows.asp

Edit: Please note we no longer offer this product due to a lack of interest and commercial viability (i.e. they were very expensive). Although we no longer sell this product we would recommend a visit to the website of 'The Greener Window Company' who continue to sell composite windows. 

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

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.

Points Of Interest.

We at Duration like to keep informed about whats happening in the world of windows and doors so when we found this article about Sapa Aluminium Systems who we are once again working with we thought we would share it. Hope you enjoy.

Supporting sustainable building

PART OF THE WORLDWIDE SAPA GROUP AND ONE OF EUROPE'S LEADING SUPPLIERS OF ENVIRONMENTALLY SUSTAINABLE AND ENERGY-EFFICIENT ALUMINIUM BUILDING SYSTEMS, SAPA BUILDING SYSTEMS DESIGNS ALUMINIUM FENESTRATION SYSTEMS.

Sapa offers architects and specifiers a wide range of innovative aluminium systems for curtain walling, doors, windows and specialist applications. In the last year it has moved to imposing new premises in Tewkesbury, Gloucestershire, bringing together operations from three locations into one new facility. The move has underlined Sapa's commitment to the future and helped cement the company's perception within the design community.

Looking to the bright future that Sapa Building Systems' new premises and improved product offering will facilitate, Sapa's commercial director, Jon Palethorpe says: "Over the past couple of years we've attracted new customers and specifiers, growing both our fabricator network and our market share, and we believe that trend will continue.

”Our newer product ranges are beginning to penetrate, as evolutions of the Dualframe range of window and door systems with enhanced thermal performance and our new unitised curtain wall system, are brought to market. Another of our strengths is that we are very well balanced across the various market sectors, selling into education and commercial projects as well as health care and affordable housing sectors."

Bringing benefits to buildings

There are many benefits to using aluminium; its light weight means it's easier to handle which can reduce the environmental impact and cost of transport; it's very strong and corrosion resistant; its durability provides architects with endless design possibilities; and its innovative design from Sapa Building Systems offers high insulation with low maintenance and almost 100% recyclability. Therefore, with environmental policies continuing to drive demand for sustainable and recycled building materials, it's perhaps unsurprising that the use of aluminium in architecture and construction is growing in popularity.

Sapa's range of aluminium curtain walling systems, doors, windows and facades takes advantage of these characteristics to provide architects and specifiers with the most effective visual and technical solutions for today's buildings. In fact, environmental performance and energy efficiency play a key role in the development of its new products.

For example, Sapa's new Dualframe Si range utilises thermal break technology which achieves exceptional thermal performance.

Sapa has also just launched its largest high performance, thermally insulated sliding door system. The Contort 160 is a sliding door with a large glass surface and minimal sightline, designed for high end spaces it can also provide total insulation, helping to reduce building's energy consumption.

Due to advances in the thermal efficiency of its products, Sapa's systems have been specified for use in several BREEAM rated buildings around the world.

Sapa Building Systems in action

The Welsh Assembly Government office in Llandudno Junction, North Wales was designed to meet the BREEAM Excellent rating required by the Welsh Assembly for all publicly procured buildings in Wales. It officially opened in October 2009 and now accommodates more than 530 staff over four storeys of open plan office space.

Demonstrating best practice and innovation in office environments, it is the first central government building in the UK to incorporate a designated public access area. Members of the public are able to come in to the area, known as 'Y Bont,' and find out more about Welsh Assembly Government services, access the internet for free, speak to the trained members of staff on hand to resolve their queries or just use the cafe.

Safety and security

The £20 million development mixes traditional, locally sourced materials with sustainable technology and architects Austin-Smith: Lord were faced with the challenge of reconciling this mix of materials with the building's modern form.

Following an earlier design by concept architects, the glazing needed a radical redesign to make it blast-resistant to meet government security requirements. The original design of flush, frameless glazing could not be made blast-resistant. Instead, Austin-Smith: Lord adopted the Powerframe system by Sapa Building Systems, which is approved under the international standard IS016933.

Sapa Building Systems was one of the few companies able to supply a blast resistant glazing system robust enough to meet the stringent security standards required. The glass is laminated with polyvinyl butyl membrane, which safely retains the glass splinters caused by a blast and is firmly clamped in position by aluminium frames supported by steel sub-frames.

The glazing effectively acts as a crumple zone in an explosion which can deflect up to 300mm to reduce the blast pressure and load on the rest of the building.

Environmental performance

While security was a key factor in the design of the Welsh Assembly building, it was also crucial that Sapa's Powerframe system performed from an energy efficiency point of view. As part of achieving the BREEAM Excellent rating, the system was required to meet the standards set out in Part L of the Building Regulations. This in itself is quite difficult to do as characteristically systems that are blast resistant include a high metal mass and are usually installed in large sections. In this instance, the mullion sizes were ten times heavier than a conventional system. Despite this, the Powerframe system is able to perform a dual function; offering the highest level of protection in addition to good thermal performance.

As one of the largest and most exposed office buildings in North Wales and only 40 metres from the shoreline, its position also presented challenges with weathering. The Powerframe system with robust design and weathering details provided architects, Austin-Smith: Lord and the main contractor Pochin Construction with both a technical and environmentally sound solution that also contributed substantially to the BREEAM Excellent rating.

Sapa Building Systems Ltd

Artical taken from: Specification Magazine March 2012 

Understanding Energy Efficiency

We at Duration understand that energy efficiency ratings can be complicated to understand - so we have put together a guide to help resolve the mystery of energy efficient windows.

It is widely known that a large percentage of the heat from your home is lost through the windows - that is why understanding energy efficiency can come in handy, helping you to save money when heating your home.

The guide explains the ratings and how energy efficient windows work. There is also some useful information on what to look out for when buying energy efficient windows.

Follow the link to see the guide:

http://www.duration.co.uk/brochures/misc/Energy%20Efficient%20Windows%20Guide.pdf