The graphic represents the range of radiation from the sun.

Ultraviolet radiation occurs with a shorter wavelength than visible light, which is shorter still than near infrared radiation which contains heat but no daylight.

Low solar heat gain low-E glass is designed to transmit a high percentage of daylight while blocking most of the UV and near infrared heat.

This is typically achieved by applying multiple layers of extremely thin coatings to one surface of the glass. The combination of materials used, their thickness, and the order in which they are applied determine the performance of the coated glass.

The low solar heat gain low-E coating acts something like a filter, designed to pass desirable daylight but reject unwanted UV and near infrared.

This is an ideal choice for hot climates where solar heat gain is a major contribution to air conditioning loads and discomfort in the home.