For many self-builders, the chance to build a dream home is also the opportunity to achieve a more sustainable lifestyle. The goal of zero carbon performance requires careful planning and research, however, and the specification of building products with real sustainability benefits, from how raw materials are sourced to eventual recycling.
Eco-friendly window and doors play a crucial role in sustainable performance – but what should you consider when planning your specification? Here’s some advice:
- Thermal performance is given as a U-value, and the lower the U-value the better the insulation. Triple glazing delivers excellent thermal insulation but check first to see if you can meet your thermal targets with high performance double glazing, or with a strategic mix of double and triple.
- Indoor climate – windows are the key to achieving the perfect balance of natural light and fresh air. Look for slim framed window designs which can maximise daylight, and systems with a range of ventilation options such as trickle vents or sensor controlled window units.
- Lifetime costs – low maintenance windows not only help your pocket but are also more sustainable as they reduce the need for repair and replacement.
- Lifetime impacts – for a true picture of sustainability, ask your window supplier for a ‘cradle to grave’ analysis of raw materials, performance and disposal.
VELFAC Glazing at Ten Oaks, Hertfordshire
Almost a decade in the building, Ten Oaks is undoubtedly an impressive family home. Architects Kirkland Fraser Moor worked with owner Ian Mays (one of the founders and now retired CEO of RES, the world’s largest independent renewable energy company) to create a ‘climate restorative’ zero carbon home with minimal visual impact on the surrounding countryside. The highly distinctive circular building – with an additional circular annexe – features VELFAC composite glazing throughout, specified for its low-U values and slim-framed, contemporary and sustainable design.
‘VELFAC triple glazed units met our thermal targets while the narrow frame design increased visibility from within the house and brought more daylight inside,’ says Ian. ‘We considered installing locally-made curved windows, but VELFAC was more cost effective and delivered the performance we needed. As a result, we opted for a faceted design where the larger window panels are as wide as possible without compromising the curved finish. The sustainability of the VELFAC aluminium / timber frame was also important,’ adds Ian: ‘Every unit is almost entirely recyclable and it’s also very low maintenance, which again supports our zero carbon ambitions. The fact that VELFAC was part of the same group as VELUX was also reassuring, as we knew we were dealing with a large, established business.’
Large full height VELFAC units – together with smaller windows and VELFAC glazed doors – are installed across the house including in a striking run of five, 2.3m wide sliding patio doors set into the external façade. An additional 24 1m wide full height glazed units have also been installed around the inner circular courtyard, of which 10 are hinged patio doors, and are set within stone ‘frames’ to create a colonnaded effect. An innovative ribbon run of VELFAC tilt-and-turn clerestory windows also wraps around the circumference of the annexe, and looks particularly dramatic when illuminated at night. In terms of frame finish, dark grey was specified for the external aluminium to minimise the impact of frame against glass while also providing a contrast with the brick built facades. Internal timber frames are finished in RAL 9010, which Ian describes as ‘a very subtle off-white which allows the windows to ‘disappear’ into the white-painted walls and against the skyscape outside’.
Ten Oaks is zero carbon in operation and a net contributor of carbon free electricity back to the grid, thanks to its solar panels. Although not yet entirely carbon-neutral Ian expects to repay the carbon embodied in the house within 40 years through this export of solar power. If this figure includes the carbon savings of Ten Oaks relative to a house using more conventional design, materials, and heating and power systems, then the payback period is only eight years.
Find out more
Contact our team for expert guidance on sustainable window specification, and for a no-obligation quote – call 01536 313 552, or visit our website for more information.