OUTDOORLIVING
Energy efficiency and rooflights – achieving excellence
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WITH THE EU 2020 ENERGY Efficiency Directive driving the construction industry to help cut the nation ’ s energy use by 30 per cent over the next two years , Vanessa Howard , Chief Marketing Officer at Roof Maker , explores the latest technical developments in the production of rooflights to support energy efficiency ...
To prevent heat loss , a pane of glass must adequately control the different elements that make up the solar spectrum : UV light , visible light and infrared light ; to become energy efficient , a pane of glass should allow the highest level of visible light to transmit through the glass , whilst simultaneously allowing the lowest level of infrared light to be transmitted , this is typically a wavelength of around 1,900 nanometers .
However , with regard to rooflights in particular , extra consideration must be applied as the horizontal positioning of the glass effects its energy efficiency and the rate at which it conducts heat loss .
TRIPLE GLAZING – IS IT WORTH IT ?
As heat rises , the heat loss on a vertical window is far less than that of a rooflight because the gas has a significantly larger area of space to rise and fall , which diminishes the rate at which the heat is lost . In a horizontal rooflight , the area is notably smaller in the direction of the heat rising and falling , which means the rate of heat loss is greater as the air has less space to travel .
If the same pane of glass is changed from a vertical position in a wall to a horizontal position in a ceiling , the U values will be approximately 30 per cent less due to convection . This is important when considering that current UK building regulations state a window must have a U Value of 1.6 or lower . If you transfer a vertical window with a U value of 1.6 into a horizontal positioning , its U value will be significantly higher .
Roof Maker manufactures a range of glazing solutions , developed under the Reflex brand to offer exceptional thermal performance , solar performance , up to 100 % UV protection , security glass and noise suppressing glass . This is a range and level of energy efficiency that cannot be achieved with double glazing alone . Roof Maker ’ s technical team has worked hard to develop a range of rooflights that offer an impressive Ug value of 0.6 in their horizontal positioning and together with clever frame design can give a total unit Uw value of less than 0.9 .
IN THE FRAME Traditionally , the frame has been the common source of heat loss for any type of window and has been a main factor of inefficient energy efficiency . However , in order to successfully combat this , Roof Maker specifies aluminum frames across its entire range of modular , flat , fixed , circular and opening rooflights , as not only does it offer the highest levels of durability and resilience due to its marine-grade powder coating , it also provides the greatest level of heat insulation and thermal efficiency , when combined with super-efficient insulating materials .
Tested to BS 6375 Pt 1 , the frame features a super insulating foam thermal break to prevent heat loss from being conducted . This , combined with the three layers of glazing and high performing spacer bars separating the glass ensures that the rooflight supports the building in retaining its interior temperature by preventing any heat from escaping .
This technology has been taken one step further with the development of Roof Maker ’ s latest Passive House accredited fixed flat rooflight , which features a patented step design that has been designed to accommodate a 30 ° difference between the outside and inside temperature . For example , if the external temperature was -10 °, the interior of the property could be up to 20 ° and condensation would not appear . Condensation is a visible indicator of thermal performance over a window system even though ventilation could be a contributing factor . On Roof Maker ’ s traditional range of rooflights a difference of 20 ° is accommodated for , as it is very rare for British weather to drop to such low temperatures .
The greatest advantage of triple glazed Rooflights however , is the feeling of comfort given by a stable temperature in the home . There are no cold and warm spots throughout the property , just a consistent , healthy and comfortable environment .
CLEARVIEW-UK . COM » AUG 2018 » 43