When I’ve got self-cleaning windows

Featured Article
21 Nov 2018

As featured in Glass Times Magazine - 2016

When I’ve got self-cleaning windows

Phil Brown, European regulatory marketing manager at Pilkington United Kingdom Limited, part of the NSG Group, comments on self-cleaning glass and its growing market in the UK.

It was 80 years ago, in 1936, that the jolly ukulele tune, When I’m Cleaning Windows, by George Formby first appeared. Perhaps in the 30s, the idea of a self-cleaning window would be seen as something from a space-age fantasy, sitting in a world of driverless cars and automated homes.

However, self-cleaning windows have been around for more than a decade now, with Pilkington announcing the launch of the world’s first commercial self-cleaning glass in 2001. The awareness of them among homeowners is still fairly low, but the market is growing thanks to reduced costs and technological developments improving the glass properties. 

Essentially, self-cleaning glass, like the Pilkington Activ™ range, gives not only the practical benefit of less cleaning, but also clearer, better-looking windows. It is often used for conservatories, orangeries, glass roofs and skylights, as these are usually the most difficult to reach and clean. 

At this time of year especially, decaying leaves pick up dirt from the ground and are blown against windows and onto conservatory roofs leaving marks behind, taking off their shine. But windows are prone to attracting dirt all year round, from the dustier atmosphere in the summer to whatever birds leave behind.

Using the forces of nature

For those unaware, self-cleaning glass works by using the forces of nature to help keep the glass free from dirt. It does this in a dual-stage process.

Once the glass is installed, its special coating requires up to five to seven days of being exposed to daylight in order to fully activate the self-cleaning properties. 
Afterwards, the coating reacts with UV light to break down and detach particles of organic dirt absorbed onto the glass, even on cloudy days. This is known as the photocatalytic stage.

Then comes the hydrophilic stage. Once a rain shower arrives, the water spreads evenly over the surface of the glass instead of forming droplets, helping to wash away the detached dirt without leaving streaks. This effect also helps improve visibility out of windows during rain showers, and decreases the likeliness of condensation appearing externally during the autumn and spring.

Should we be lucky enough to have a long dry spell, a quick hose down of the windows is also enough to wash the dirt away.

Not just self-cleaning

A further benefit of self-cleaning glass is that it can be combined with other products to create superior performing windows. For example, products such as Pilkington Activ™ Blue or Pilkington Activ SunShade™ combine both self-cleaning coating and solar-control properties. This solution is well-suited for conservatories, orangeries and glass roofs because it limits the amount of heat passing into the building, while also keeping the glass clean.

On the other end of the spectrum, the coating can also be combined with low-e glass, allowing convenient self-cleaning properties on windows that also provide thermal insulation. This is particularly suitable for glass roofs and conservatories in colder climates and glass box extensions.

Mansion House orangery [BOXOUT CASE STUDY]

Within the Pilkington Activ™ family sits Pilkington Activ SunShade™, which has both self-cleaning and solar control properties. Last year, this glass was installed into Mansion House, a grand Victorian house in St Helens. 

The installation formed part of a £3million refurbishment of Mansion House, with the Pilkington Activ SunShade™ units specified for the roof of the building’s orangery. It offered the orangery the hassle-free properties of self-cleaning glass, while retaining the original Victorian structure and reducing the heat passed from the sun through into the building. 

Built in 1850 by a wealthy solicitor, the Grade-II-listed building is today owned by the charity Age UK Mid Mersey, functioning as its headquarters. 

Added convenience

While we’re not looking to put trusty tradesmen out of the job, self-cleaning glass such as the Pilkington Activ™ range can significantly reduce hassle for homeowners and reduce the costs of hiring a window cleaner. 

For commercial building management too, having this glass can reduce the need to regularly hire cleaners to go up on scaffolding or cradles to service larger properties.

Self-cleaning glass is more modern reality than space-age fantasy, and we will continue to see it increase in popularity over the next few years, as awareness of its benefits grows.