IGU - Insulated Glass Unit

In the pursuit of sustainable architecture, the integration of advanced thermal glass, specifically IGU's, plays a pivotal role. This technology, essential for modern energy-efficient buildings, offers multiple benefits, fundamentally changing how buildings interact with their environment.

Understanding IGU's

Insulated Glazing Unit is a type of insulating glass that includes an additional coating on at least one of the panes. This coating is designed to prevent heat from escaping from the interior to the exterior during colder months. Normal glass, like soda-lime silicate glass, is largely impervious to long-wave infrared radiation, i.e., thermal radiation. This means the incoming thermal radiation is first absorbed by the glass and then emitted as secondary heat through its surfaces​​.

The Role of Emissivity in Glass

Glass has a high emissivity for thermal radiation (ε = 0.84) due to its high absorption in this wavelength range. To reduce heat emission, a thin metallic coating is applied, which can decrease the glass's emissivity to just a few percent. Metals like silver (ε = 0.02) have much lower emissivity compared to glass and are used in coatings to reduce emissivity. These are referred to as low-emissive or low-e coatings. Modern thermal protection coatings can achieve emissivity levels ranging from ε = 0.01 to 0.03. These coatings are nearly invisible to the human eye, maintaining high transparency in both the solar and visible wavelength ranges and offering a high color rendering index​​​​.

Addressing Overheating in Buildings with Large Glass Areas

For buildings with extensive glass surfaces, the use of thermal insulation glazing alone may not suffice. High solar energy inputs can lead to overheating, as incoming radiation passes unhindered through the thermal insulation glazing into the interior. In such cases, additional sun protection or combined heat and sun protection glazing is advisable. This approach ensures that while the building remains insulated against heat loss, it also doesn't accumulate excessive heat during sunnier periods​​.

The Takeaway

Incorporating advanced thermal glass technology in building designs aligns with the growing need for energy efficiency and environmental sustainability. By understanding and utilising the unique properties of IGU's and complementary sun protection strategies, architects and builders can significantly enhance the energy efficiency of buildings. This leads to reduced energy costs, improved comfort levels for occupants, and a smaller environmental footprint, marking a step forward in sustainable building practices.