How I Rate Blackout Curtains

I rate blackout curtains on two separate scales: first for their material health, and second for their health function. Beyond being materially healthy, a blackout curtain also serves a health function: darkness. Light at night suppresses melatonin and disrupts sleep and circadian rhythm, so a curtain's health benefit depends on how completely it blocks light. This is one of the unusual cases (along with shower curtains and mattress protectors) where synthetics often outperform organic fabrics, which can't achieve total blackout on their own.

Material Health

Blackout curtains are made with fabric, sometimes several layers of it. Blackout blinds are made with wood or fabric. You can see the Material Health Scales for wood here and fabric here. This is just one aspect of how I rate a curtain, and on its own it doesn't account for how well the curtain actually does its job.

Health Function

This is the scale I use for that job. It's consistent across products, running from lowest to highest. For blackout curtains:

• Highest blocks 100% of light with a true blackout backing, with no light leak through the fabric itself.

• High blocks around 95%, enough to darken a room but not achieve total blackout.

• Moderate blocks most light; these are usually labeled Room Darkening shades.

• Low filters or dims light without meaningfully darkening the room.

• Lowest provides little to no light blocking.

Non-Toxic & Organic Blackout Curtains Guide

What are the best quality blackout curtains?

The best blackout curtains have three features:

1. They are made from safe materials that do not off-gas harmful VOCs or shed harmful chemicals into your home. The best curtains will have either GOTS certification, verifying they are made from organic fibers and organically processed. Or they will have OEKO TEX certification, verifying that they have been tested for harmful chemicals and meet either Class I (safe for babies) or Class II (safe for adult touch) standards. This means they don’t contain flame retardants, carcinogenic azo dyes, formaldehyde, phthalates, or other chemicals bad for health.

2. They are the appropriate level of blackout. Not all blackout curtains are 100% blackout. It is impossible to make organic 100% blackout curtains because a synthetic fabric is necessary to achieve that.

3. You will actually use them. Blackout curtains were historically made with heavy black material, making them cumbersome and not aesthetically pleasing. Now, options exist that are lightweight, have suction cup functionality, come in attractive patterns and custom sizes.

All three are important consideration when buying blackout curtains to improve your sleep quality, room temperature, and room darkness.

What are the best blackout curtains for a nursery?

Blackout curtains made with polyester or similar synthetic material with Class I OEKO TEX certification are the best choice. This is because OEKO TEX Class I means the fabric was tested and met strict levels deemed safe for babies to touch. This means no flame retardants, phthalates, PFAS, or PVC are present in them, all common in standard versions. While synthetic fabrics aren’t always the best choice for material health in other contexts, it’s actually best for this situation because it is the only material that is capable of blocking 100% of light. Natural and organic fabrics cannot be woven tightly enough to achieve this, unless you layer many layers of them.

Having GreenGuard GOLD certification also acts as a second layer of protection ensuring that they won’t off-gas.

Non-Toxic Blackout Curtain Fabric

Are there any organic blackout curtains?

There are 95% blackout curtains made with 100% organic cotton, and there are 100% blackout curtains made with OEKO TEX certified linen and polyester. Making 100% blackout curtains with 100% natural materials hasn’t been done yet— making blackout curtains with GOTS certified organic fibers and GOTS certified processing techniques is very difficult to get an organic blackout curtain with no light coming through.

What is OEKO TEX Class I certification for blackout curtains?

OEKO TEX has four product classes: I, II, III, and IV. Class I products have met the strictest requirements and limits, and are certified to be safe for babies and toddlers to touch. Babies and toddlers are more vulnerable to harmful exposures because their detoxification systems aren't fully developed, they engage in hand-to-mouth behavior more often, and their cells are dividing rapidly as they grow, meaning they are more susceptible to mutagenic exposures.

Class II means direct skin contact is safe for adults, and applies to textiles like sheets and pillowcases.

Class III and IV are still much safer for you than standard fabric processing— I really want to emphasize that! — and are reserved for items without direct skin contact, decorations, and home textiles you don't touch very often (like most curtains, for example).

Why is GreenGuard GOLD certification important for non-toxic blackout fabric?

While fabrics don't usually have big issues with off-gassing VOCs, blackout curtains are a little different for 2 reasons.

• First, heat increases the rate of off-gassing, and fabric can get very hot when hung in a window, especially if you're using them to keep out hot, bright sun.

• Second, most blackout curtains are made with PVC or other coatings that release harmful VOCs . It's hard to make synthetic or natural fabric block light completely, so these are commonly added.

This is an important distinction from the vast majority of the product group.

Is polyester safe in blackout curtains?

Yes, if it has OEKO TEX certification that ensures it’s been tested and meets strict limits and doesn’t contain flame retardants, carcinogenic azo dyes, or PFAS.

Polyester itself is relatively stable once it's made, meaning it doesn't make its way into your body easily. In that sense, it's safe.

Polyester's health issues come from the chemicals that sometimes tag along with it. Antimony is used in the chemical reaction to make polyester, and it can remain on the polyester in the final product. BPA, phthalates, and other additives are very commonly mixed with polyester to make the fabric softer, more durable, flexible, and colorfast. Recycled polyester is made from plastic of unknown origin and date, so can contain unknown harmful chemicals.

Polyester tested according to safer standards, can be essentially harmless to the user. This is especially true if it has GRS, OEKO TEX, or MADE SAFE certification. OEKO TEX Class 1 polyester is definitely the highest standard it can meet. Any kind of polyester is still a better choice of fabric than PVC (polyvinyl chloride).

There are also reasons to choose polyester and synthetic fabrics over natural ones for certain applications, like for blackout functionality or PFAS-free waterproofing.

I use it for lower-contact uses in my home, like my shower curtain and blackout blinds.

What about making DIY blackout curtains with safe fabric?

Two Sisters EcoTextiles blackout fabric is the best for DIY blackout curtains. For DIY blackout curtains that are organic or non-toxic, you can attach this fabric to existing curtains by sewing or using fabric tape to attach it to the backside. Two Sisters EcoTextiles has been committed to truly organic fabric for decades and uniquely carries lots of GOTS certified organic and OEKO TEX certified drapery fabric, including sheers, wide-width options, and non-toxic blackout liner fabric. You can also make DIY blackout curtains without blackout lining by using two layers of their heavyweight fabric. A great option if you can sew straight lines and are up for making your own curtains.

Chemical Additives in Standard Blackout Curtain Fabrics

Are blackout curtains toxic?

Many standard blackout curtains are made from a polyester front layer with a foam or PVC (polyvinyl chloride) backing. Foam and PVC can both off-gas harmful VOCs, and this process is sped up when exposed to heat and sunlight, which curtains often are. Other blackout curtains may be cotton or another natural material, but coated in acrylic or other plastic material. You can read more about foam health in my guide here, and more about fabric and its (surprisingly chemically intensive!) processing here.

Are blackout curtains bad for you?

No, as long as 3 things need are considered:

1. First, the material they are made with should be healthier than average. Blackout curtains made with PVC and softened with phthalates, or that off-gas can be bad for you. If you choose non-toxic blackout curtains made with healthier materials like OEKO TEX or GOTS organic certified fabric, they are safer. All of the blackout curtains and blinds listed above are made with healthier fabric than standard versions, which is important so you're not exposed to off-gassing VOCs present in foam-backed or PVC-coated fabrics.

2. Second, use them correctly to replicate day and night for your circadian rhythm. It is definitely beneficial to your health to block excess, human-made, unnatural light out from your bedroom at night. However, it is also very beneficial to wake up to the sun's natural rays. A couple of options exist to make blackout curtains good for both sleep, waking up, and your circadian rhythm overall:

   Use 100% blackout curtains, but don't seal 1 crack: this is the easiest option (which I use myself) that balances blocking out nearly 100% of streetlight at night, but allows morning sunlight to come in through the little 5mm gap at the top of the window. Sunlight emits tens to hundreds of thousands of times more light than a streetlamp, so even a small crack will send a signal to your eyes and brain that it's time to wake up. For reference, the full moon emits 1 lux, a streetlamp emits around 50 lux, and direct morning sunlight on a clear day emits 100,000 lux. I wear an eye mask at night, which tends to fall off by morning, so the combination works well for me.

   Completely seal out light from the outside using 100% blackout curtains, plus whatever you need to keep them in place— and use a simulated sunrise alarm clock or programmed lightbulb to wake up. Or, use a regular alarm and just open your blinds or go outside to get natural sunlight and set your circadian rhythm for the day.

3. Consider air flow: choose blackout blinds or curtains that still allow you to crack a window for ventilation. Otherwise, crack the door to the room, use an air purifier, or turn on your HVAC to circulate air during sleeping time. A buildup of carbon dioxide, which we breathe out naturally while we sleep, can cause issues with sleep quality and daytime alertness.

Are there flame retardants in blackout curtains?

In many blackout curtains, yes. In many states and cities, it's a requirement that curtains used in public spaces meet standards for low flammability set by the National Fire Protection Association (NFPA). Ironically, natural fibers have flame retardants added to them more often than polyester and other synthetic fibers, because natural fibers burn more readily. The easiest way to know if your curtains have flame retardants is by looking for GOTS certification or OEKO TEX certification. You can also confirm with the company they don't use them though you have to trust they know their supplier and processes well.

Why are flame retardants in blackout curtain fabric bad?

Flame retardants are well-known endocrine disrupting chemicals, and are linked with immune system dysfunction and neurodevelopmental issues like ADHD. While they’re being phased out in some, they’re still routinely added to fabrics, especially drapes and curtains. Many flame-retardant brands are still available on Amazon, for example. Companies are not required to disclose whether their product contains flame retardants, so asking or looking for certification is the best way to ensure they aren’t present.

Health Benefits of Non Toxic Blackout Curtains

What are the benefits of blackout curtains for sleep?

The main benefit of blackout curtains is circadian rhythm regulation. Outdoor light pollution from street lamps, cars, neighbor's porch lights, and street signs easily finds its way into your bedroom through standard blinds and regular curtains at night, when it should be totally dark. The full moon on a clear night generates 1 lux, but a single LED street light generates 50 lux. Even a very small amount of night time light (over 5 lux) can disturb your clock genes, cause circadian rhythm problems, or prevent deep sleep.

Blackout curtains can also be very helpful if you or your baby needs to nap or sleep during daylight hours.

Finally, blackout curtains can dampen sound and act as an insulator, keeping your bedroom cool and shaded from the sun when it's hot out, or keeping it warmer when it's cold out.

In short, they have benefits for everyone, even if you're not working a night shift and need sleep during the day.

How dark should my bedroom be at night for healthy sleep?

Your bedroom should have less than 5 lux of light while you're sleeping for ideal health. Even a very small amount of night time light (over 5 lux) can disturb your clock genes and cause circadian rhythm problems.

Home Benefits of Blackout Curtains

Can blackout curtains keep heat out?

Absolutely, yes. Sunlight is a mixture of visible light, UV rays, and invisible infrared light that we feel as heat. Blackout curtains block all of these, keeping your room significantly cooler.

Blackout Curtain Aesthetics

How can I make blackout curtains look better?

Use a portable suction cup blackout curtain to cover just the windows, and hang a regular set of curtain panels in front. When you're ready to impress, simply remove the suction cups and your home is aesthetically pleasing again!