Some of our clients reach out with the same frustration. They turn off the lights, expecting the room to finally go dark, but it just does not.

Not bright enough to fully see everything, but not dark enough to feel comfortable either. There is always that faint glow sitting in the room. You start noticing where it might be coming from. The top edge. One side. Maybe the bottom.

So you go back and adjust the curtains again. Pull them tighter. Shift the fabric. Try to close that small gap you did not notice before.

Somehow, it still feels the same. At this point, most people assume the curtains are the problem. That they picked the wrong fabric or did not go thick enough. Sometimes that is true. But more often, it is something else entirely.

Light has a way of finding its way in, even when everything looks covered. And once you start paying attention to it, you realise it is not just about the curtain itself. It is about how the whole setup is working together, or not.

Blackout Curtains Not Working? The Problem Might Be the Gaps

The first thing many people notice is the fabric itself. They assume the material is too thin. Sometimes that is true, but more often the real issue is light leaking from the top, sides, or bottom of the window.

Blackout curtains can block the majority of light passing through the fabric, but they still cannot stop light that enters around the edges. Sleep guidance from Sleep Foundation and The Sleep Charity both point out that blackout curtains help darken a room, while additional measures such as pairing them with a blackout blind can improve the result when outside light is still entering the space.

This is why a room can still feel bright even when the curtain fabric itself is doing a decent job. If the rod is too narrow, the panels stop short of the wall. If the curtains are mounted too low, light slips in above them. If they barely touch the floor or sill, the glow from outside can still collect around the lower edge.

In homes, this is one of the biggest reasons people say, “I bought blackout curtains, but my room is still bright.”

Every Curtain is Not Designed to Darken a Room

Some curtains are sheer, light-filtering, loosely woven, or without lining; they may reduce glare during the day while still allowing a noticeable amount of brightness into the room. That can work well in a living room but is completely disappointing in a bedroom.

Sleep Foundation has highlighted in a review that blackout curtains are intended to block most outside light and support a darker sleep environment. If your priority is rest, nap time, shift work, or blocking early sunrise, a decorative curtain alone often will not be enough.

This is where many homeowners feel misled. The curtain looks substantial in product photos, but what they really needed was room darkening or blackout performance, not just privacy.

If your space is meant for sleeping, look closely at whether the curtain is truly blackout or simply heavier than average.

A good place to compare is Joydeco’s Blackout Curtains collection, which specifically focuses on room darkening, privacy, and thermal benefits. Joydeco’s product and collection pages also highlight blackout options in velvet and linen styles for people who want stronger light control without giving up the look of the room.

Light at Night Affects More Than Mood

People often describe this problem in emotional terms. The room feels unsettled. Sleep feels lighter. Mornings start earlier than they want.

There is a real reason for that. Much research has been done, and it has been found that light at night can drastically disrupt circadian rhythms and is associated with poorer sleep outcomes. For example, a review published in 2019 in Somnologie explains that although you are sleeping, if light is present, it remains influencing your circadian rhythms, sleep, and ultimately mood. Therefore, if you feel your room is bright even with the curtains closed, it's the right time to address this issue.

The Rod May be Too Narrow or Too Low

This is one of those details that seems small until you see the difference. Curtains that are mounted only to match the exact width of the window leave obvious channels for light to enter. The same thing happens when the rod is stuck too close to the top of the frame - the curtain might look like it's covering the glass, but let a surprising amount of light in from above. It sneaks in a bit during the daytime, but when the sun dips below the horizon or it's at dawn, the problem gets a lot more noticeable.

Generally, in most rooms, it helps to back off a bit and give the curtain some breathing room. Moving the rod up a tad and making it a bit wider totally flips the way everything falls into place. The panels don't bunch up, but instead hang more smoothly, graze along the wall when you slide them open, & close up neatly when you need them to.

It's a tiny tweak, but it tends to make the whole place feel a heck of a lot more together without needing to swap out the curtains at all. If you are unsure whether your current measurements are part of the problem, Joydeco has measuring resources that walk through width, height, and hanging preferences in more detail, including How to Measure Your Windows for Perfectly Fitted Curtains and How to Measure for Curtains: A Joydeco Step by Step Guide.

A lot of rooms do not need different curtains. They need better coverage.

Curtain Color and Lining Make a Bigger Difference

People tend to focus on style first, which makes sense. You want the room to look good. But if the problem is brightness, the lining and density of the fabric often matter more than the front color.

A light colored curtain can still perform well if it is properly lined. A dark curtain can still disappoint if it is unlined or loosely woven. This is why two curtains can look equally substantial in photos and behave very differently at night.

That is also why velvet blackout drapes are such a popular choice for bedrooms. They combine visual weight with functional light control. On Joydeco’s blackout collection pages, velvet blackout options are presented specifically as solutions for privacy and peaceful bedrooms, not just as decorative pieces.

If your room feels bright, look beyond the color name and ask what is happening behind the face fabric.

Layering Usually Works Better Than Forcing One Product to Do Everything

If the room needs serious darkness, layering is often the point where everything starts working better. The Sleep Charity specifically recommends well lined curtains together with a blackout blind when outside light remains a problem. That advice lines up with what homeowners experience in practice. A shade or blind handles the glass itself. Curtains handle softness, insulation, and the remaining edge glow. Practically, using two layers tends to feel more balanced than expecting one curtain to handle everything on its own.

We have a guide on layering curtains and shades that walks through how this works in real spaces, especially where both light control and overall finish matter. It also touches on things like fabric samples and one on one design support, which can make the decision feel a lot less uncertain before ordering.

If a bedroom still feels brighter than it should with just one set of curtains, layering is usually the point where things start to come together.

The Fix is Often More Practical Than Dramatic

People sometimes assume the answer is buying thicker, heavier, more expensive curtains. Not always. Sometimes the fix is widening the rod. Sometimes it is switching from decorative panels to true blackout curtains. Sometimes it is adding a lining. Sometimes it is accepting that a single layer will never fully solve a streetlight problem and adding a blind underneath.

Final Thoughts on Controlling Room Light

When a room feels bright despite having the curtains closed, there's likely a reason for this. Usually, it's a combination of several little things e.g. light leaks around the edge of curtains or the curtain's material does not completely block out the light but rather softens the light. Sometimes the issue will be that any one layer may not be appropriate given the way that the space gets used.

Generally speaking, once you identify the reasons for the light entering the space, you'll find it much easier to implement an appropriate solution.

In bedrooms especially, it helps to think about what the space really needs. Some rooms just need a softer feel. Others need proper privacy. And some do not feel right unless they are fully dark. The answers usually sit somewhere in between, but asking those questions early saves a lot of trial and error.

If it is still not clear what would work best, it can help to step back and look at the whole setup rather than just the curtain itself. That is where Joydeco’s free design consultation and measuring guides tend to be useful. They focus more on how the room actually feels at night, which is often the part that matters most.