Which insulation material is commonly known for reflecting heat back into the room?

Foil-backed insulation is a highly effective material for reflecting heat back into the room because of its shiny surface, which acts like a radiant barrier. This layer is designed to minimize heat transfer by reflecting radiant heat rather than absorbing it. When installed on the interior side of a wall or ceiling, foil-backed insulation helps to keep warmth inside during colder months by reflecting the heat generated by heating systems back into the living space.

In contrast, unfaced insulation lacks any reflective properties and primarily serves to resist heat flow through conductive and convective mechanisms. Shredded polystyrene insulation, while beneficial for its insulating properties, does not have a reflective quality to redirect heat. Similarly, shredded fiberglass insulation, although an effective thermal insulator in stopping air movement, does not exhibit these reflective characteristics either. Therefore, foil-backed insulation stands out as the material specifically recognized for its ability to reflect heat.