6. Install Attic Insulation
While attic fans may not help significantly to cool your home, attic insulation can help a lot. Insulation keeps cooler air in your home from escaping through the ceiling. If you have central air, also seal ducts especially at vents and registers, where you could be losing up to 20% of you cooled air. While the tax benefits aren't as generous as they were, you can still get tax credit worth 10% of the material cost, up to $500.