Basic passive heating and cooling techniques like spray foam insulation and shutting blinds are an effective ways to change the temperature in your home with out mechanical help. A recent blog piece from Lennar explains how these passive techniques can help your HVAC system work more efficiently and more importantly save you money on your utility bills.
One passive cooling technique is the installation of radiant barriers, which involves relatively cheap materials and can lower heat access up to 25%:
If you’re thinking of installing a new roof soon, or have an open attic, a radiant barrier on the attic ceiling can help prevent heat gain throughout your home. The barrier material is made of reflective aluminum, which reduces the heat radiation transfer that occurs as the sun strikes your roof.