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What Are Blackout Curtains and How Do They Work?

What Are Blackout Curtains and How Do They Work?


Aoife O.
May 10, 2021

Blackout drapes are an affordable, stylish, and useful home furnishing option that does more than looking good on your windows. Blackout drapes and curtains block sunlight from entering the room through the window. This can help you sleep better, lessen sleep disorder symptoms, and help reset your circadian rhythm.

The Science Behind Blackout Curtains: How They Work

Blackout drapes may seem like a futuristic concept but the science behind blackout curtains is actually quite simple. Blackout drapes are regular drapes that have a lining or back that is made of a tightly woven fabric. Natural light and uv rays are unable to penetrate the drapes, resulting in a pitch-black room that is an ideal environment to sleep in. Room darkening curtains can block out 99.9% of natural light, provided they are hung correctly. The multi-seasonal nature means they can be enjoyed all year round.

Blackout Curtain Benefits

Energy Saving and Temperature Control

Most homes will have the central heating or air condition running while they sleep, depending on the season. However, poorly insulated windows can run up your energy bills.

Fortunately, thermal blackout drapes can help keep your bedroom at a steady temperature by preventing hot or cold air from escaping. Your heater or AC won't have to work as hard, and you'll sleep more comfortable without temperature fluctuations.

Looking for more ways to maintain a comfortable temperature while you sleep? Consider our moisture-wicking cooling sheet sets or check out our article What to Look for in Bed Sheets to learn more.

Sunlight Blocking

If you want to block out light from a bright room, blackout drapes are the answer. A pitch-black bedroom is the ideal sleep environment as slivers of sunlight through your drapes are enough to disturb your sleep. Natural light alerts your circadian rhythm to wake but if you work night shifts blocking sunlight from your bedroom can help you get valuable sleep when the sun is shining. They will also keep the heat of the sunlight out of the room and avoid overheating.

Sound Blocking

While blackout drapes will not create a soundproof room, they are thick enough to create a sound barrier. Some blackout drapes are made with triple layers that can reduce some outside noise. If you live in a highly noise polluted area or you work from home, thick blackout drapes could reduce noise to help you focus on your work and sleep when you need to.

Blackout Curtain Styles

  • Grommet: Curtain headers installed by looping fabric with metal rings

  • Rod Pocket: Slip-on insulation through a slit in the drape

  • Tab Top: Curtains hang from the loop from a curtain rod

  • Pinch Pleats: Fabric is pinched at the top so curtains look pleated

Lining Options

  • Blackout-Lined: Made of heavier polyester lining to create a stiff drape

  • Foam-Backed: May not be 100 percent blackout but keep the soft folds of the drape

  • Thermal-Lined: Backed with heat-trapping fabric to keep the room warm but may not be 100% blackout

  • Privacy-Lined: A cotton-poly blend that is soft and blocks out natural sunlight


Do White Blackout Curtains Work?

White blackout curtains can block out just as much natural light as any other color drape. Blackout curtains can block uv rays, sunlight, heat, and noise to some degree. Blackout drapes are available in many colors, not just black. They can save you money on energy costs by keeping the heat inside and help you get a better night’s sleep.

How Are Blackout Curtains Made?

Blackout fabric for curtains is made of a tightly woven material of polyester or cotton and layered to the back of a cotton, suede, polyester, or velvet curtain. A blackout liner to your current drapes could block a certain amount of light and could be a cost-saving solution too. Liners can sometimes be less expensive than made-to-measure curtains.

What Makes a Good Blackout Curtain?

Installation of the blackout drapes is just as important as the quality of the fabric. Light filter leakage occurs when the curtain pole is hung too low or the metal rings are too large. A good blackout curtain will block 100 percent of UV rays and natural sunlight to create a pitch-black room.

Are Blackout Curtains Energy Efficient?

Blackout drapes reduce energy costs by keeping valuable heat inside your home and not allowing it to escape through your window. Twenty-five percent of home heat is lost through your windows so installing blackout drapes in every room can boost energy savings, upgrade your home style, and improve sleep quality too.

Are Blackout Curtains Soundproof?

Blackout drapes may not create a 100 percent soundproof home but they will lessen noise pollution somewhat due to their multi layer of fabric design. Much light and sound enters the room via your windows so if you live in a noisy neighborhood or work from home, thick blackout curtains could offer you some relief from noise pollution.

Are Blackout Curtains Toxic?

Blackout curtains can contain Volatile Organic Compounds (VOCs) that are chemicals found in common cleaning supplies. But, polyester is hugely popular clothes and curtain fabric that goes through the same treatment as other furnishings and is used worldwide every day. The majority of our home furnishings are treated with some chemicals but not enough to cause negative health consequences.

What's the Difference Between a Blackout Curtain and a Room Darkening Curtain?

Blackout drapes and room darkening curtains are similar but blackout drapes provide much more light blockage. Blackout drapes are thicker than room darkening curtains and block much more uv rays. Blackout drapes may be best in a bedroom and room darkening curtains could work well in every other room in your home.

Are Blackout Curtains Good for the Baby's Room?

Babies and infants sleep much more than adults as sleep is vital to their development. Blackout curtains will help your baby get a good night’s sleep by keeping natural sunlight and uv rays out of the baby’s room. Blackout drapes can be very useful when sleep training, creating an inviting sleep space for your toddler.

Can Blackout Curtains Be Washed?

Blackout drapes can not be machine washed as the strenuous activity of the machine could damage the blackout fabric. It is best to spot clean as you would with a foam mattress. Lay the curtains flat and gently blot the curtain with a soapy sponge or cloth, followed by a dry cloth to remove excess liquid and air dry.

Can Blackout Curtains Be Ironed?

When ordering blackout drapes online they often come folded up neatly in their package. Unfortunately, this means when you hang them, you may notice little wrinkles here and there. While you may be tempted to throw your curtains on the ironing board, hang them and use a garment steamer for more gentle ironing.

Can Blackout Curtains Be Dry Cleaned?

Blackout curtains may not survive a dry clean as the process involves intense heat. Depending on the blackout fabric in some cases, rubber. It may be best to spot clean instead of using a gentle approach with a damp soapy cloth. Check the label and ask your dry cleaner if your curtains need an intense cleaning.


The best bedroom blackout curtains are thick and block out 100% uv rays and natural sunlight. Your blackout drapes do not necessarily need to be a dark color, white blackout curtains can block the same amount of light. Blackout drapes are available in many styles, colors, and affordable options. Blocking natural light from entering your bedroom could help you sleep better as sunlight alerts your circadian rhythm to wakefulness. Blackout curtains block uv rays and could reduce your energy costs. The blackout fabric can also block some noise pollution, which could offer some relief if you live in a noisy area or work from home.

Disclaimer: Nolah does not provide medical advice. All resources on the Nolah blog, including this article, are informational only and do not replace professional medical counsel. Talk to your doctor about any health, mental health, or sleep-related issues.

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