It's tough to know what truly differentiates blackout shades from room darkening shades. In fact, people in the blinds and shades industry use these terms interchangeably all the time. Here's the difference in a nutshell:
Blackout shades use a fabric that blocks 100% of all incoming light, while "room darkening" usually refers to almost any shade that uses a fabric that blocks between 95% and 99% of the light that enters your room. Anything that blocks less than 95% of the light is usually referred to as light filtering.
When they're properly installed, blackout shades make your room almost completely dark. However, no shade can totally block out all light, so it's impossible to make your room pitch black. There will still be light that shows along the sides of your shades during the day. With blackout shades, a little "halo" of light still sneaks through around their outer edges.
To create this effect, blackout shades typically use an opaque material like PVC or Mylar to line the fabrics used, and they're also designed to fit tightly to your window casing. This drastically reduces light seepage.
Most often, you use blackout shades for rooms like your:
Some types of blackout shades cut out almost all light, giving you the darkest possible room. They reduce the light that seeps through that little "halo" we talked about earlier. These include:
If the room you want dark gets direct sunlight whenever you want to use it, blackout shades make good sense.
Beyond the nearly pitch-black environment they create, fully blocking out the sun's rays gives blackout shades a few distinct advantages over their room-darkening counterparts:
Because there is some confusion around this term, let's shed some light on the matter. Room darkening generally refers to any window treatment that dramatically reduces the incoming light to your room. However, they won't make your room nearly pitch black like blackout shades do. They just make it noticeably darker than before.
Common types of room darkening shades include sheer shades, zebra dual shades, and pleated shades. You can purchase all of these window treatments with opaque materials that block much of the light that normally enters.
You can also use room darkening shades for your bedroom or home theater. But didn't we also mention blackout shades are commonly used for these rooms?
In reality, you can use either. What really matters is how dark you'd like it to be in each of these spaces. Room darkening shades and blinds work best when direct sunlight does not shine into your room. Or, if you are a heavy sleeper and do not need blackout shades, they make a good fit for your bedroom.