How to reduce heat on a south-facing room with a single-paned, tempered glass window.

Method 1: Tempered, single-paned windows aren’t as susceptible to heat as dual-paned windows, so you can ostensibly use any film that meets your needs. For simple heat rejection, a nice ceramic film with a low VLT percentage will keep the room cooler. Conversely, if you’re more concerned about light, then you can opt for a reflective film with perhaps less heat rejection.