Buildings are responsible for approximately 36% of total energy consumptions and 40% of CO2 emissions globally, according to the International Energy Agency.
With the recent revision of the Energy Performance Building Directive (EPBD) last July, the pressure for energy efficiency in buildings has never been stronger, pushing for further use of smart technologies.
On the other hand, green building certifications such as BREEAM, LEED and more recently WELL, all recognise that sustainability is not just about energy efficiency – it must also consider indoor environment quality. In recognition of this, the revised EPBD also strengthens, for the first time, health and well-being criteria. Among the key criteria to consider for a quality-built environment are daylighting and views to the outdoors, supported by large scientific evidence.
Glass plays a key role in this area. These concerns have thus opened the door for great innovations in the glazing industry. Traditionally valued by designers for aesthetic aspects, but also by occupants always looking for more daylight and connection to the outdoors, the use of glass has significantly increased in recent decades.
In parallel, the growing stringency in building energy performance targets has also given rise to the debate about the amount of glass that should be used, as windows are often seen as a source of heat loss in winter and overheating in summer. Plus, the provision of daylighting can come with unintended consequences to occupants in the form of thermal discomfort and glare.
To respond to the design challenge of creating both energy efficient and comfortable daylit spaces, ‘smart’ glazing has appeared on the market over the last few years. These are capable of dynamically adapting their optical properties to the outdoor weather conditions, the indoor conditions, or the occupants’ preferences, with no moving parts.
Among the most innovative and mature smart glass technologies on the market is SageGlass electrochromic (EC) glass. It enables the control the amount of visible light and solar heat gain entering a space, over a wide range that varies between 60% and 1% in visible light transmission and 0.40 to 0.05 in solar g-factor.
The modulation of light and heat can be controlled automatically via sensors, at the touch of a button, with a swipe in a mobile application, with voice commands, or with a higher-level command from a building automation system.
EC coatings can be integrated in double or triple glazing units, with a second low emissivity coating to meet the specific insulation requirements. Different exterior aesthetics can be achieved by adding tints or another coating to the exterior glass pane.
By intelligently adapting its tint to the conditions, SageGlass can significantly reduce energy bills. During heating seasons, SageGlass decreases the need for heating by providing passive solar gains when clear, it reduces cooling loads during cooling seasons when tinted, and allows optimum daylight harvesting potential all year long, limiting the use of electric lights.
In terms of occupant comfort, SageGlass is also able to efficiently manage glare and overheating issues without using blinds, ensuring optimal daylight provision, and a continuous view and connection to the outside world.
Previous studies done by the Hilson Moran consultancy firm have shown that SageGlass could save 10% to 20% on HVAC loads and in electrical lighting use when compared to conventional facade solutions. Moreover, traditional systems like shades and blinds are complex and costly to install and maintain, while SageGlass is easy to install and does not negatively impact people’s comfort nor usable space. The aesthetic of the facade is also preserved.
Such technology provides interesting benefits in terms of regulatory compliance, such as meeting Part L of UK Building Regulation’s requirements on buildings’ energy use and CO2 emissions. Improved ratings in certification schemes like BREEAM, LEED and WELL can also be achieved with SageGlass, which constitutes an elegant solution valued by organisations caring about the well-being, health and performance of their employees and customers, while managing costs.
Offices, healthcare centers, schools, hotels, restaurants are among the many applications already benefiting from SageGlass today.