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How to Avoid Light Bleed on the Edges of Blinds

Dark grey Duette honeycomb blinds on a bedroom window behind a soft pink bed and modern décor.

November 26th, 2025

Light bleed; those narrow streaks of light that escape around the sides of blinds is a surprisingly common frustration, particularly in bedrooms and media rooms where complete darkness is essential. Whether it’s early morning light disturbing your sleep, or streetlights interrupting a cosy evening, light bleed can disrupt the atmosphere and functionality of a space.

So why does it happen and how can you fix it?

Why Light Bleed Happens

Even the most effective blackout fabrics can’t block all light if the blind isn’t fitted in a way that closes off the edges. Most blinds are fitted inside the window recess, creating a sleek, minimal look. But this fitting style requires a small gap on each side of the blind so it can move freely and that’s exactly where light creeps in.

This is why people often assume their “blackout blinds” aren’t working but in truth, it’s usually the fitting, not the fabric, that’s the issue.

Quick Fixes for Light Bleed

If you're dealing with light coming in around the edges of your blinds, here’s a quick overview of the most effective solutions:

  • Install side channels to seal the sides
  • Choose snug-fitting blinds, like Duette®
  • Opt for an outside recess fitting
  • Layer with curtains for added coverage
  • Ensure precise measuring and installation

  • 1. Fit Side Channels for a Complete Seal

    One of the most reliable ways to eliminate light bleed is to install side channels; slim tracks that run vertically along the inside edges of your window frame. The blind sits inside these channels, blocking any light from slipping through the sides.

    This method is especially effective with blackout roller blinds and Duette® blinds, where the fabric glides neatly within the channel for a crisp finish.

    ⚠️ Not all blinds are compatible with side channels, so it’s worth seeking expert advice before choosing this option.

  • 2. Choose Duette® Blinds for a Precision Fit

    Duette® blinds are not only known for their energy-saving honeycomb design but they’re also particularly effective at reducing light bleed when fitted correctly. The cellular fabric is dimensionally stable, which means it won’t twist or sag like other materials might over time.

    Duette® blinds are made-to-measure, so when installed by a specialist, they sit snugly within your window frame helping to minimise gaps where light can escape.

    If you're aiming for maximum convenience, smart electric options are also available. These allow you to lower blinds to the perfect position with precision, further reducing unwanted light leaks.

  • 3. Opt for an Outside Recess Fit

    An alternative to fitting blinds inside the window recess is to mount them outside on the wall above the window. By choosing a wider blind that overlaps the edges of the window, you can block light much more effectively from all sides.

    This option is particularly useful in bedrooms, and it also gives more flexibility for styling with curtains or pelmets. However, this does not completely remove all light bleed but will reduce.

  • 4. Layer With Curtains for Full Coverage

    If you already have blinds fitted and still notice light bleeding through, adding a layer of curtains can be a simple yet effective fix. Curtains with a blackout lining can mask any residual light coming in from the edges or top of the blind.

    This approach is also great for softening the overall look of the room while boosting insulation and privacy.

  • 5. Get Expert Measuring and Installation

    Even a high-quality blind can let in light if it’s not measured and fitted accurately. A blind that’s slightly too narrow or slightly off-centre can exaggerate gaps and make light bleed more noticeable.

    That’s why a professional in-home consultation is worth considering, especially for older homes where window frames aren’t perfectly square. An expert will assess the space and recommend the most effective fitting and blind style for your needs.

  • Info

    A Note on “Blackout” Expectations

    It’s important to remember that blackout fabric blocks light from passing through the material, but unless edge gaps are addressed, it won't deliver a completely darkened room.

    A proper blackout setup combines the right fabric and the right installation method and that’s where made-to-measure options like Duette® blinds, fitted with precision, make all the difference.

Hillarys' advisor consulting a customer at their home

Final thoughts

Light bleed is a common but solvable issue. With the right approach, whether that’s fitting side channels, switching to a snugger blind style like Duette®, or layering with curtains you can significantly improve light control in any room.

And if you're not sure where to begin, a consultation with a specialist can help you find the perfect solution tailored to your space and how you use it.

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