Summer Thermal Comfort
In summer, strong direct sunlight strikes people and interior surfaces,
creating overheating and discomfort. Windows with low solar
heat gain coefficients will reduce the solar radiation coming
through the glass and associated discomfort. Low solar heat gain low-E
glass (spectrally selective) reduces heat gain while still providing
sufficient light and view.

Source: Lawrence Berkeley National Laboratory
(Lyons and Arasteh).