Enerlogic window films provide insulation equivalent to double glazing at a quarter of the cost. They are easy to install without replacing frames or glass, and reject up to 76% of solar heat in warmer climates while allowing winter sunlight through. Compared to double glazing, Enerlogic films cost $7,000 to install on a 3 bedroom home versus $25,000 for double glazing, and can increase the insulation of existing double glazed windows.