Complete blackout conditions are very important in hospitality guestrooms. We all know that guests place a high priority on not having streams of light flowing into their room as soon as the sun comes up. With traditional drapery we solve for this by using blackout drapery with returns to the wall (For more information, check out our post “What are Hospitality Drapery Returns?”). Here, we will be considering how to create the same blackout situation with roller shades, specifically when they are inside mounted within a window.

As we have outlined in our Roller Shade Styles Resource, shades can either be inside mounted or outside mounted. A majority of the time designers seem to go with an inside mount system due to the streamlined, minimalist aesthetic it gives off. Logically, in order to fit a roller shade inside a window’s edge, the roller shade must be made smaller than the actual window and therefore, small cracks of light may be visible along the sides of the roller shade (check out our 3 Tips To Prevent Light From Leaking Around Roller Shades In A Hotel Room post). This isn’t an issue when roller shades are found in public spaces, where light fastness is not a concern, but if they are being used in a guestroom, and without blackout drapery to be paired with, light leakage becomes a serious issue.

In this context, Side and Sill Channel become a must. They are essential pieces of shaped metal installed along the side and sill of a window which hold the roller shade fabric or cover the space between window edge and roller shade edge. These elements are usually installed directly into the sheetrock and therefore block all light leakage.

All of this seems simple enough until you are told that there are multiple types of roller shade Side and Sill Channel. At that point some of you may be thinking “this has gone on long enough, just tell me which kind is best.” That’s definitely our intention but the truth is they both have their own pros and cons and place of best use. Let us explain!

“L” Channel

L Channel is typically used as Sill Channel. Because of it’s “L” shape, the roller shade comes to rest behind the channel and light is blocked from coming in through the crack that is sometimes formed between the roller shade hem bar and the sill of the window. L Channel is easy to install and comes in multiple colors. It allows the roller shade fabric to move backward and away from the channel and therefore the potential for light leakage should be considered slightly greater than with the U Channel.

“U” Channel

U Channel is typically used as Side Channel and is truly a channel through which the roller shade edges move. U Channel is installed directly into the window edges, or may be installed outside the window. Either way, roller shade edges are matched up and inserted within the ‘U’ and therefore all light is blocked in this seal. U Channel does require for the roller shade to be precisely lined up with the channel and when this does not happen, it may cause slight problems. U Channel is incompatible with fabric wrapped hem bars (they are too thick to fit within the U). U Channel can also be used as Sill Channel if requested although it is not recommended due to the preciseness in which the roller shade would need to fit into the channel.

Helpful Tips and Things to Remember:

Often times windows may be treated with only Side Channel, especially when an external or fabric wrapped hem bar is specified as the ‘bulkiness’ of the hem bar creates a light seal as it rests on the window sill.
When Side Channel is being used with a dual system, it is recommended that the blackout shade be located behind the sheer shade. That way Side and Sill Channels will be installed closest to the window and will not interfere with the operating of either shade.
If a dual system is being used and the blackout is specified as the shade closest to the room (with sheer behind) then Side Channel of any kind should not be used, as the functionality of the sheer would be blocked by the Side Channel. If Side Channel is a must then only L Channel should be used.
An alternative to Side and Sill Channel would be to couple roller shades with drapery. For example, and inside mount blackout roller shade coupled with side panels that overlap the edges of the window would create a light fast environment inside the guestroom. A sheer roller shade coupled with a blackout drapery which can cover the window completely would do the same.

You might like: “QC Roller Shade Specifying Tips: Channels”

We hope this information has given you a better understanding of your options and will help increase great communication for projects in the future!

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