DOORS WINDOWS & GLAZING FOCUS 55


WINDOWS TO FUTURE SUSTAINABILITY


Emily Page of window fabricator Stedek, charts the evolution of energy-saving windows, from early innovations to low carbon solutions for future homes.


W


indows might only make up a tiny part of the average building – but when it comes to


sustainability, their impact is huge. A brick wall, for example, has a fraction of the U-value that a window provides. However, since few of us fancy living in brick boxes without any light, we have to live with the fact that glass is inevitably less thermally effi cient than other types of structure.


The good news is that window technology has advanced drastically over the last 40 years. It wasn’t all that long ago, historically speaking, that single-glazed timber framed windows dominated the market.


While aesthetically pleasing, they present signifi cant sustainability challenges. Together with single panes of very basic glass, they unsurprisingly offered very poor energy effi ciency, and created major thermal weaknesses in the structure of the building. This was followed by the fi rst wave of aluminium windows – a world away from the modern, high-performance aluminium windows on the market today. Still largely single-glazed, they offered a much more durable option than timber – but as a metal, aluminium’s thermal conductivity posed a problem. Early aluminium windows struggled to retain heat, leading to higher energy bills and carbon footprints.


THE DOUBLE-GLAZING BOOM The ‘0s brought two signifi cant shifts – the development of double glazing, and the rise of PVCu.


Double glazing dramatically improved thermal effi ciency. And PCu did the same – advanced profi les with multi-chambered designs reduce energy consumption for heating and cooling. They were also durable, cost-effective and recyclable, making them an excellent choice.


INNOVATIONS IN GLAZING However, while the frame material plays a crucial role, the glass itself signifi cantly impacts a window’s sustainability.


Advancements in glazing technology have unlocked new possibilities for energy-effi cient windows. Low emissivity features a special coating that re ects long-wave thermal radiation (heat) back into the building, reducing heat loss in winter.


Solar control glass allows visible light to pass through while re ecting infrared radiation from the sun, keeping the interior cooler in the summer months. Replacing air in the gap between panes with argon gas which provides lower thermal conductivity, further enhancing insulation.


SMALL COMPONENTS – BIG DIFFERENCE Spacer bars also play a crucial yet often overlooked role in window performance. These thin strips separate the panes of glass within a double or triple-glazed unit. Traditionally, metal spacer bars were used – however, these brought the same problem as aluminium windows. They conducted heat, creating a “thermal bridge” that reduced the effectiveness of the glazing.


More advanced warm-edge spacers, made from materials like foam or


composites, have signifi cantly lower thermal conductivity. They minimise heat transfer between the panes, enhancing the overall performance.


GREAT LOOKS, GREAT PERFORMANCE During that initial double glazing boom, there weren’t many who’d say they preferred the look of PVCu to timber. PVCu windows were more durable, cost-effective and easier to maintain – but when it came to aesthetics, they were extremely basic. You could have any colour you liked, as long as it was white. In choosing them, homeowners and housebuilders were having to make a trade-off – worse looks for better performance. Today, that trade-off is no longer necessary. Manufacturers have made huge strides, allowing them to deliver high-performance windows that also provide exceptional aesthetics. It means that the window products available today offer better energy effi ciency than they’ve ever done – without compromising on performance in other vital areas too.


Emily Page is director of Stedek WWW.HBDONLINE.CO.UK


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84