One of the most often raised questions when it comes to window treatments energy eficiency is which ones are better: thermal curtains or cellular blinds. The answer can’t be given just like that, because there are many factors to be taken into consideration when doing this estimation.

In the first place, the main comparison factor is the R-value, which is an index of how efficient the thermal insulation is. There are ways to measure it, but when buying window coverings, most of the times, the r-value is supplied by the manufacturer. However, this value alone is not enough. For instance, if your thermal insulating curtain has a very good R-value, but you omit to install it like indicated in the instructions, you’ll lose some efficiency. If you don’t want to attach the curtian sides to the walls with magnets or tracks because you don’t want to stick anything on the walls, the r-value will be lower than the one given by the manufacturer, because the cold air drafts will form and will circulate towards the center of the room.

With cellular or honeycomb shades, the story is the same: you need to make sure that you follow the installation instructions if you want to take advantage to the full of their insulating properties.

Last but not least, old style windows are less energy efficient than modern ones, which are double glazed and have a special gas between the two sheets of glass, thus providing superior thermal insulation.