How it Works
When the sun shines against windows, a large amount of thermal energy is transmitted inside the building, heating the atmosphere inside and causing “solar heat gain”.
- Solar heat gain coefficient (SHGC) is the amount of heat transmitted by a window.
- The more windows a building has the greater its SHGC.
- Higher SHGC windows require large air-conditioning and HVAC systems to counteract solar heat gain.
- Up to 38% of building’s total energy consumption is for air-conditioning to counteract solar heat gain.
Some buildings have low-e windows installed to block out the heat caused by the invisible near infra-red light coming from the sun. However these windows do not deal with the nearly 50% of solar heat gain that comes from the sun’s light that is in the visible spectrum.
- Smart windows made with SWITCH's photochromic/ electrochromic film darken when exposed to sunlight to dynamically reduce SHGC and glare while preserving views and taking advantage of natural daylight.
- The film can be 'switched' in low light conditions by the application of a small electric charge and the tinting disappears, allowing occupants to optimize their lighting environment.