Buyer Guide for Shades & Blinds

If your shades are letting light in on the sides, the shade is probably doing its job; the fit and mount are the problem. A shade light gap sides issue usually comes from inside-mount clearance, a slightly uneven window frame, fabric width deductions, or choosing blackout fabric without side channels. Shade Light Gap Sides Fix Measure the window width at the top, middle, and bottom. Level the brackets and center the fabric roll. Choose outside mount if you want more edge coverage. For bedrooms, nurseries, and media rooms, add optional L-shape side channels for near-total blackout. The annoying part: blackout fabric can be 100% blackout and still let light show at the edges. The fabric blocks light through the shade. It doesn't magically seal the space between the shade and the window frame. What you see Most likely cause Best fix Thin glow on both sides Normal inside-mount clearance Outside mount or side channels Big beam on one side Brackets are uneven or shade isn't centered Re-level and recenter Light at top corners Roller/cassette sits forward Add valance, outside mount, or channels Uneven side gap Window opening isn't square Measure in 3 spots before reordering If this is for a guest room, a little glow may be fine. If it's for a day sleeper, nursery, or projector room, don't try to talk yourself into “good enough.” Side light will be the first thing you notice at 6:12 a.m. Why Side Gaps Happen Inside-mount shades need clearance. The headrail, brackets, roller tube, and fabric all need enough room to move without scraping the window frame. That means the fabric is often slightly narrower than the full opening, especially on roller shades. Tiny gap. Giant sunbeam. The shade light gap sides problem gets more obvious with blackout shades because the center of the window goes dark while the edges stay bright. Your eye jumps straight to the contrast. With light-filtering fabric, the whole window glows, so the side gap feels less dramatic. The usual causes are simple: The shade was measured from one spot instead of top, middle, and bottom. The window frame narrows slightly in one area. The shade is inside mounted, so it needs operating clearance. The roller fabric is narrower than the mounting hardware. The brackets are not level by even a small amount. The window trim blocks a tighter fit. If you're new to ordering custom shades online, mount type matters as much as fabric choice. “Custom size” means the shade is made to your measurements. It doesn't automatically mean the room will be pitch black unless the whole system is planned for blackout coverage. A useful test: turn the lights off at night, turn on a phone flashlight outside the shade edge, and look from the bed or couch. If the gap looks bad from the place where you actually use the room, fix that view first. Inside Mount vs Outside Mount Inside mount looks clean because the shade sits within the window frame. Outside mount blocks more edge light because the shade overlaps the trim or wall around the window. For blackout, outside mount usually wins. Mount type Looks best for Light control Tradeoff Inside mount Clean, built-in look Good, but side gaps are normal Needs depth and square frames Outside mount Maximum coverage Better edge blocking Covers trim or wall space No-drill inside mount Renters and apartments Good with accurate measuring Still has side clearance Blackout + side channels Bedrooms and media rooms Best near-total blackout setup More parts, more planned look Renters have a special problem: you want the room dark, but you also want your deposit back. AOSKY's no-drill options use spring-tension mount brackets with no tools and no adhesive, which is why they make sense for apartments. If that sounds like your situation, our guide to no drill shades for renters is the next read. One caution: outside mount is not always allowed in a rental if it requires screws in trim or drywall. In that case, choose no-drill inside mount, order carefully, and consider optional L-shape side channels if the product setup supports them. The side channels do the job outside mount normally does: they block the side beam. Fix Current Shade Gaps Start with the boring fix first. Check the brackets. A bracket that is off by a few millimeters can make one side gap look twice as large as the other. Lower the shade fully, step back, and look at the bottom rail. If it slopes, the brackets need attention. If the bottom rail is level but one side still glows, the shade may need to be shifted left or right inside the brackets. Try this before reordering: Lower the shade fully and check whether the bottom rail is level. Make sure the shade is centered in the window opening. Confirm the brackets are seated evenly and not pulling the roller forward. Look for trim, handles, locks, or tile that may be forcing the shade away from the glass. Photograph the gap during daylight from the place where it bothers you most. Don't trim blackout fabric at home. That can fray the edge, damage the coating, and make the shade roll poorly. Don't add permanent adhesive strips to a rental window frame unless you're ready to repair paint later. And don't assume a darker fabric fixes side light. Darker fabric blocks light through the shade, not around it. If the shade is the wrong size because of a measuring mistake, check AOSKY's FREE Measurement Assurance. AOSKY offers a one-time free remake per order for eligible sizing mistakes reported within 30 days of delivery. Coverage doesn't apply to every fit issue, such as uneven walls or non-square windows, so send clear photos with a tape measure when you contact support. For a temporary fix tonight, hang blackout curtains wider than the window and let them overlap the shade edges. It isn't as tidy as a proper shade setup. It works. Order Better Blackout Coverage For true sleep-level darkness, think in layers: blackout fabric, correct mount, and edge control. A blackout roller shade or blackout cellular shade handles the glass area. Outside mount handles the overlap. Optional L-shape side channels handle the side light gap by giving the fabric edge a track-like barrier. That's the cleanest answer for people who keep saying, “The shade is dark, but the sides are killing me.” If you're shopping AOSKY blackout shades, look for the side-channel option where available and treat it as an upgrade for near-total blackout. It is optional, not standard. For most living rooms, you won't need it. For a bedroom with east-facing windows, a nursery nap schedule, or a home theater, it's worth planning for from the start. Fit also affects comfort. The U.S. Department of Energy notes that tightly installed cellular shades and side tracks can improve window covering performance, especially around heat loss and solar gain. Different goal, same basic lesson: edge gaps matter. For kids' rooms, choose cordless operation when possible. The U.S. Consumer Product Safety Commission recommends cordless window coverings when young children are present. Before you order, take 5 minutes and do this: Measure width at the top, middle, and bottom. Measure height on the left, center, and right. Check window depth if choosing inside mount. Decide whether the room needs privacy, room darkening, or near-total blackout. Ask support before ordering side channels for unusual trim, tile, shallow frames, or crank handles. A shade light gap sides fix is easiest before the shade is made. After that, you're adjusting, layering, or remaking. FAQ Are side gaps normal? Yes, small side gaps are normal with many inside-mount shades because the shade needs space for brackets, fabric movement, and window-frame variation. If you need stronger blackout, outside mount or optional side channels work better than simply choosing darker fabric. Can blackout shades leak? Blackout fabric can block light through the material while still allowing light around the sides, top, or bottom. For bedrooms and media rooms, pair blackout fabric with outside mount coverage or optional L-shape side channels. Do side channels block gaps? Side channels help block the side beam by covering the space where light slips around the shade edge. AOSKY's optional L-shape side channels are best for customers who want near-total blackout, especially in sleep rooms. Should renters avoid drilling? Renters should avoid drilling if the lease restricts holes in trim, walls, or window frames. AOSKY no-drill shades use spring-tension mount brackets with no tools and no adhesive, which makes them a better fit for apartments. What gap is acceptable? For living rooms, a small glow may be fine. For nurseries, bedrooms, shift-worker sleep, or projector rooms, treat visible side light as a real fit issue and choose stronger edge coverage. AOSKY makes custom shades for real homes, including apartments, older windows, and rooms where morning light hits hard. Order free fabric samples, measure carefully, use 24/7 live chat if the frame looks tricky, and ask about optional L-shape side channels when you want near-total blackout. Custom sizing takes about 5 minutes online, with fast free shipping, 100% Satisfaction Guarantee support, FREE Measurement Assurance, and a 3-Year Limited Warranty.