Leo Pyrah of Pilkington UK outlines the role of solar control glass in the battle to get to net zero carbon by 2050, and explains what could be holding the solution back from being specified more widely by architects
The race to hit net zero carbon by 2050 has renewed discussion in Government and across the building design industry about how we make our new and existing buildings more energy efficient.
When glazing’s role is considered here, the industry has historically focused on trapping heat in with low-emissivity glass, led by Building Regulations, resulting in reduced demand for heating spaces in colder months. Indeed, improving the thermal efficiency of the glazing used in our built environment will be important to meeting the net-zero target.
But preventing solar energy from being transmitted into buildings through windows and facades will be equally pertinent for lowering emissions. Solutions like solar control glass will help alleviate this issue, resulting in less energy used by mechanical cooling systems.
The issue of overheating, and its impact on energy efficiency, is forming part of Government consultations surrounding Building Regulations. This could introduce great change in the way we design buildings in as little as 12 months’ time.
With regulations driving change, it could lead to greater proliferation of solar control glass – catalysed by manufacturer innovation in the category. This is coupled with an increasing ability to combine glass coatings, so not only can one glazing solution deliver solar control performance, but it can be toughened, self-cleaning and thermally efficient too – delivering on multiple objectives for technical architects.
New specifications for solar control glass
Solar control glass is currently being specified in all manners of climates, and for all sorts of projects.
For example, Pilkington recently installed 50,000 square metres of solar control glass at the Palm Tower, a new landmark building in Dubai’s iconic Palm Jumeirah district. The advancement of solar control coatings has allowed the tower to be clad entirely in glass while resisting the desert heat, keeping a naturally cool temperature inside for occupants.
It’s solar control glass’ increasing ability to be combined with other solutions, such as self-clean or acoustic glazing, that is opening new opportunities for its specification.
Solar control glass in the home
While the commercial sector strides ahead in using solar control glass to curb energy use and maintain comfortable temperatures indoors, the UK residential market lags behind.
In the forthcoming Building Regulations Part L (Conservation of Fuel and Power) consultation in England, overheating is expected to be a focus area, not only for commercial buildings but also for residential properties.
This is unsurprising given that last year’s hot summer drew a lot attention to just how serious the overheating issue in homes currently is. Research by Loughborough University published in the Building Research and Information Journal (2017) outlined how deaths related to overheating could triple by 2040.
Given solar control glass’ ability to reduce the amount of heat transmitted into buildings via windows, and subsequently reduce the risk of overheating without the need for mechanical cooling, the Part L consultation could lead to regulations that place more importance on its specification in the home. Currently, Part L only recognises the problem of solar heat gain in non-residential properties, where solar control glass or shading devices are required for large glazed projects to meet the solar gain benchmark.
Currently, we’re waiting to learn how the Government proposes to address these growing concerns. For new, non-residential properties, the current ‘notional building’ used in the Regulations is based on a maximum g-value of 0.4, where 40 per cent of the total sun’s energy is transmitted. A lowering of this value could drive the market for more highly performing solar control glass. As an alternative to counterproductive designs such as reducing glazed areas, we could also see more importance placed on architects specifying glass with better solar control properties in the home.
Zero energy buildings
Undoubtedly, over the next two decades we’ll see a step change in the way buildings are designed, driven in part by increasingly stringent Building Regulations, with each project striving to be a zero-energy building.
Looking ahead, advanced technologies like dynamic and switchable glazing – glazing which can react to daylight exposure and limit heat transmittance – may also provide a solution for homes and commercial buildings.
For now, it will be important for architects to watch the Government’s consultations surrounding energy efficiency and overheating closely. By the end of next year, the specification of solar control glass is likely to extend beyond the large commercial projects we see frequently now and to be seen in far smaller commercial and residential projects.
Leo Pyrah is product manager at Pilkington UK