Which are the most energy efficient window treatments?

Window treatments are able to reduce heating and cooling costs by preventing heat transfer (either in or out). Cellular shades – often referred to as Honeycomb Shades – are best able to prevent heat transfer. They can reduce heat transfer by a remarkable 65 percent! Plantation shutters aren’t far behind, at 60%. A blackout roller shade can reduce heat transfer by up to 55%, and a venetian blind can reduce heat transfer by as much as 45%.