Reflective insulation (also known as foil insulation) is essentially a barrier usually made from aluminum foil or aluminized polyester. Much like other forms of insulation, reflective insulation may help reduce energy costs by blocking the heat that radiates from the sun, onto your roof, through your attic, and on into your living space. It is that natural transfer of heat from the outdoors that causes your systems to work harder and be less energy efficient. By blocking that heat gain in your attic, reflective insulation will also substantially reduce the air temperature surrounding your HVAC equipment and duct work.