In sunny climates, sun beating down on the roof can cause high attic temperatures and threaten the comfort of the adjoining rooms below. It can also cause air conditioning equipment to work harder, especially if the air conditioner or ducts are located in an uninsulated attic. A sun barrier consisting of a reflective foil blanket installed on the underside of the roof rafters or a foil coating adhered to the underside of the roof decking reflects radiant heat from the sun back toward the sky. This helps minimize solar heat gain while increasing comfort and energy savings.