If your lower blinds work well but the glass above them stays bright, you may only need to cover the transom. Blackout blinds for transom windows should be chosen around that upper opening's shape, mounting space and operating height. Keep the lower treatment if it still provides the privacy and light control you want, and if the new hardware can work independently. Choose a full-height covering when separate mounting is impractical.
A replacement lower blind will not cover a separate pane above its headrail. Locate the unwanted light before replacing anything. Keep the lower treatment if it still does the job you need.
Find out whether the transom is the problem
A transom is an upper glazed opening above a door or another window. Pella's transom guide describes how these windows add light above the main opening, in rectangular or arched forms. Here, the focus is on the glass above a bedroom window, although the same distinction between upper and lower areas can help with other rooms.
Close your existing lower covering at the time the room is too bright. Look at the upper glass from the place where light bothers you, such as the bed or a reading chair. Is that pane uncovered? Or is the brightness coming around the lower blind, through its fabric, or from somewhere else?
A bright upper rectangle and a narrow border around a lower blind are different problems. Covering the transom can address the former; it does not correct a lower blind's fit. Our bedroom light audit can help if several sources compete for attention.
Observe first, without taping a makeshift covering to the glass or climbing onto furniture. A photo from your normal viewing position can record the light path, but it is not a measurement of blackout performance. If the source is unclear, investigate before ordering custom sizes.
Choose what the new covering will control
You can cover the upper opening separately or span both levels with one treatment. Shared trim does not require matching products.
Keep the lower covering and add an upper treatment
This is worth considering when the lower blind still works, looks good and gives you the daylight or privacy you need. The new treatment manages the upper glass without changing the lower routine. For example, you could keep a light-filtering lower shade for daytime use and close a suitable upper covering when you want that pane dark.
The upper treatment needs its own suitable mounting space, and the lower headrail must remain accessible. Look for a lower shade roll or folded stack that projects toward the upper opening. Those parts can occupy space a straight-on photo makes easy to miss.
Cover both levels with one treatment
A full-height shade or curtain can make sense when the upper recess is unsuitable for a separate unit, or when you want to cover the entire window group together. It avoids a separate daily adjustment at the transom, but closes off both levels at once.
Check the chosen product's actual mounting requirements and coverage. A curtain rod installed below the transom leaves the upper glass exposed. A shade mounted above it needs enough length for the whole group, plus whatever clearance its manufacturer requires. Do not extend an existing product beyond its intended dimensions or assume a larger blind can attach to the old brackets.
| What you want to preserve | Layout to investigate | What could rule it out |
|---|---|---|
| Lower blinds that already meet your needs | Separate upper treatment | No suitable upper mount, inaccessible control or hardware interference |
| One action to cover the complete group | Full-height shade or curtain | Insufficient mounting space, unsuitable dimensions or blocked window operation |
| Daylight through the upper glass at selected times | Operable upper treatment | A control you cannot comfortably use |
| An arched architectural feature | Shape-specific specialist advice | A rectangular product that does not match the opening |
The table compares layouts, not measured darkness. Two products are not automatically better than one. For the broader product categories, see our blackout-blind buying guide.
Check reach before choosing blackout blinds for transom windows
An upper shade can fit its opening and still be awkward to use. Check the motion you would repeat each morning as well as the access needed for installation.
For a manually operated system, confirm where your hand needs to go through the full movement. If daily use would mean standing on the bed or stretching across furniture, choose a different arrangement or ask about a product designed for that height. Do not assume an extension pole or remote can be added to a manual blind. Our manual-versus-motorized shade guide explains the broader operating tradeoffs.
High placement also does not make accessible cords harmless. The U.S. Consumer Product Safety Commission recommends cordless coverings where young children may be present. Health Canada likewise advises replacing coverings with long accessible cords and keeping climbable furniture away from windows. Follow the selected product's instructions; cordless does not remove every window hazard.
Measure the upper opening as its own opening
Give the upper and lower areas separate names on your sketch, even if you intend to buy only one new treatment. Record the opening you want covered, the proposed mounting position and the nearby hardware. Do not use the width of the entire decorative surround as the size for a recess-mounted upper blind.
For ShadeCort S, the measuring guide requires at least 1.18 inches (3 cm) of unobstructed recess depth. It calls for width readings at the top, middle and bottom, and height readings at the left, center and right. Use the smallest width and the smallest height, submit the exact opening measurements, and leave production deductions to the manufacturer.
On a short transom, a glazing bead or the lower blind's bracket can take up a noticeable part of the available space. Measure where the proposed frame would sit. A deeper point farther back in the opening may not be usable by that product.
Keep inches and centimeters consistent across the record. Before ordering, compare your dimensions with the live configurator and have support review an unusually short, uneven or obstructed opening. Minimum recess depth is only one condition, not a complete fit approval.
Also identify whether the upper glass is fixed or opens. If it opens, its hardware and full movement need to remain usable. Check access for cleaning and for the window below, too. A covering should not turn a routine latch or screen task into a removal project.
Where an enclosed-frame system belongs
ShadeCort S is a custom-sized, manually operated cordless blackout system with an aluminum-alloy frame and honeycomb non-woven polyester fabric. Its enclosed side tracks are designed to eliminate edge light gaps when the system is measured, assembled and installed correctly.
For an upper-window layout, consider it only if the individual opening is suitable for the frame, the submitted dimensions are orderable, the unobstructed recess is sufficient, and you can operate it conveniently. Its standard no-drill installation is designed for a suitable window recess. That is not approval to attach it to any narrow crosspiece or to span unsupported trim.
The system is not a motorized high-window solution, and it is not suitable for arched openings. If your transom is out of reach or has an unusual shape, another product or mounting approach may serve you better. Keeping the lower blinds does not make an unsuitable upper opening suitable.
If the opening and operation are suitable, compare the current product options with your upper-opening measurements.
Watch the fitting sequence before ordering
The official ShadeCort S video shows assembly and installation in a standard compatible opening. Use it to understand the perimeter frame and fitting sequence, then compare that work with the space available at your window. The video is not a demonstration of every transom configuration or a recommendation to install a high unit without appropriate help.
Take these details to the order page
Prepare a small record before selecting a custom size:
- One photo of the whole window group with the lower blind both open and closed.
- A close view of the upper opening, its corners and the dividing trim.
- Separate upper-opening width, height and usable-depth readings, with the unit noted.
- Photos of brackets, handles or other items near the proposed mounting plane.
- Whether the upper glass opens, which lower treatment you are keeping and how you expect to operate the new covering.
If the mounting surface, shape or operating arrangement is uncertain, send those details to support before placing the order. Ask for confirmation of that particular opening, not just whether the product works with the word "transom."
Keep a useful lower treatment unless there is a reason to change it. Once the upper opening's dimensions, installation conditions and operating access are confirmed, compare the current options on the product page.
Three questions before you decide
Can the transom stay covered all the time?
It can be a reasonable choice if you do not want daylight through that pane, but consider the whole room before committing. Preserve any required window operation and access. A permanently positioned treatment is a different purchase from an operable blind that happens to be left closed; choose a product intended for the arrangement you need.
Will privacy film solve the upper-window light problem?
Do not assume a film sold for privacy also blocks the light you want to stop. Check its actual light-transmission and blackout description, and ask the window manufacturer about compatibility with your glazing. Film is not a substitute for checking an opening's mounting and access needs when you are considering a separate blind.
Can a rectangular framed blind cover an arched transom?
Not by treating the curved glass as a rectangular recess. ShadeCort S is not suitable for arched openings. Seek a shape-specific solution or professional advice about a separate room-side covering, and confirm its mounting requirements before ordering. Do not buy a rectangular unit on the assumption that trim or leftover fabric will fill the curve.
