Blinds are best used in the summer. They are able to reflect out the sun light to reduce heat gain by 45%. If you do need the natural sunlight but still want to save on heat you can adjust the blinds to reflect on to a lightly-colored ceiling. A lightly-colored ceiling can diffuse the light without adding much heat or glare. Another advantage of window blinds is being able to adjust it to allow in a breeze from an open window while at the same time deflecting the heat from the sun.

Here is great place to learn about the different blind and window shutter options available.

A shade’s ability to reduce heat loss in the winter depends on several factors including fabric style, thickness and color. Obviously a closed weave fabric will be better at controlling room temperature than hole weave pattern like this. It’s best if you let the drapes fall over on to the floor or windowsill and also overlap in the middle. Velcro could be used to tightly attach the drapes at the sides and bottom. If they don’t touch the ceiling a cornice should be installed over the top. Two sets of shades hung over each other could also help. If all done properly it’s possible to reduce heat loss by up to 25%. Most standard window shades reduce heat loss from a room up to around 10% by default.