When you're searching for the best blackout curtains, you're looking for one thing: total, pitch-black darkness. You want to block out the harsh morning sun, intrusive streetlights, and keep your bedroom perfectly dark for optimal sleep. The truth is, blackout curtains help restore naturally better sleep that humans are accustomed to.
Unfortunately, the term "blackout" has become widely misused in the home decor industry. Many products labeled as such are merely "room darkening," often relying on a cheap, light-filtering construction that will leave you severely disappointed.
This article is written by Sleepout’s Team of blackout experts, including the first producers of blackout lining (Roc-lon®), the only producer of Greenguard Gold Blackout Fabric (Sleepout® Fabric), the largest mill operators in the world producing over 60 million blackout curtains in the last 200 years.
The difference between a true blackout curtain and a cheap imitation isn't just a matter of performance, it's a critical difference in manufacturing, cost, and even safety.
The Woven Fabric Myth: Why "Blackout Weave" is a Lie
The biggest deception in the blackout market revolves around woven blackout fabric.
Many companies, particularly those focused on cutting costs, market their curtains as "blackout" based purely on a very tight, dense weave of the fabric. The reality? Woven fabric is not truly blackout. It might dim a room, but it will always allow some light penetration. This type of fabric is only a fraction of the cost—sometimes as low as 10% of the cost of true blackout material—making it highly profitable for companies to pass off as the real deal.
In fact, this deception has led to legal action. There have been lawsuits against companies that sold this woven fabric to hotels as "blackout," when in reality, it failed to meet the industry standard for 100% light blockage.
-
⚠️ The Key Takeaway: If a seller claims their curtains are blackout solely because they are "tightly woven" or "triple-weave" without a specialized light-blocking layer, they are selling you a room-darkening curtain, not a true blackout product.
If you have purchased curtains based on a false claim of 100% blackout from a company that only uses woven fabric, you should request a full refund.
The Hidden Dangers of Blackout Coatings
True 100% blackout fabric requires a specialized blackout material to be effective. This light-blocking function comes from a coating or lamination layer.
Since light-blocking material must be used to achieve the namesake, the coating process introduces potential toxins to the base fabric.
-
Hidden, Toxic Layers: Some vendors, often unfamiliar with proper textile chemistry, try to market their products as "coating-free" or "just woven" to appear more 'natural.' When they do use a blackout layer, it's often a laminated backing that is hidden between other layers of fabric. This hidden layer can be made with cheap, toxic chemicals and is deliberately concealed from the consumer, making the final product much more toxic. Always remember, if it’s blackout, it contains a blackout layer, it’s not just fabric.
-
Uncertain Sourcing: Many modern curtain sellers, especially newer companies, do not manufacture their own fabric. They are simply buying pre-made fabrics on the open market, often with no idea what chemicals were actually used in the coating process. They don't make their own fabric.
Any company that makes claims about their blackout curtains being "free of chemicals" or "non-toxic" must be able to back it up with official, third-party testing results. Without that documentation, you are taking a risk with chemicals that may off-gas Volatile Organic Compounds (VOCs) into your home, especially when heated by the sun.
Fun Fact: Our teammate was the first to introduce PVC-free blackout to the world through Roc-Lon® in a commercial setting for hotels and other commercial interiors.
Why is All Blackout Fabric Made with Polyester? Is there any other option?
Ultimately, a true blackout curtain will never be made of truly 100% organic material.
Since true blackout requires some form of blackout material to be included with the base fabric, polyester is almost always a better base layer choice than organic or partially organic materials like cotton or linen. This is because the synthetic fabric threads of polyester can be more heavily controlled and integrated with the required blackout coating or layer, ensuring a durable and light-proof final product. There is currently no known way to achieve true blackout using a base layer made exclusively of organic material, but we are working on it!
The Future of Blackout: Introducing Sleepout Fabric
Not all blackout materials are created equal. The most advanced, safest blackout solutions are designed with transparency and health certifications at the forefront.
Sleepout® Fabric is an example of a specially engineered blackout material designed to achieve 100% light blockage without the hazardous chemicals found in many traditional or cheaply manufactured coatings.
Here are key facts about Sleepout Fabric:
-
Guaranteed 100% Blackout: Sleepout Fabric is guaranteed to block 100% of the light with its specialized material.
-
Water-Based Formulation: It uses a water-based formulation instead of harsh, industrial solvents to achieve 100% blackout. This is what helps the fabric achieve prestigious certifications like GREENGUARD Gold.
-
PVC-Free and TPU-Free: The earliest and cheapest way to make blackout curtains was using Polyvinyl Chloride (PVC), now most blackout that contains PFAs use, Thermoplastic Polyurethane (TPU). Sleepout uses neither and is certified free of harmful chemicals found in these procceses by OEKO-TEX STANDARD 100.
-
The Non-Toxic Process: Ohe process involves taking the same safe thread material and applying it in blackout form. This is very different from using PVC or TPU and adding toxic chemicals like formaldehyde. Sleepout fabric instead blocks more light, has the highest insulation value, and the highest durability compared to any other method of production.
-
Superior Durability: The specialized coating process ensures the blackout layer lasts much longer than any other blackout coating because the fabric is made in a more strict and careful process, resisting breakdown and ensuring maximum light blockage for years to come.
- No Fire Retardants: Sleepout Fabric does not use harsh chemical fire retardants. These chemicals are typically reserved for commercial buildings where strict fire codes mandate their use, but they are not necessary (and carry chemical risks) for residential home use.
Your Checklist for Buying the Best Blackout Curtains
To ensure you are getting a high-quality, safe, and truly effective blackout product, follow this checklist:
-
Look for GREENGUARD Gold Certification: If you want true blackout, use a GREENGUARD Gold certified blackout fabric. This is the highest standard, confirming the lowest chemical emissions.
-
⚠️ Warning on Certifications: If a company advertises they have GREENGUARD and not GREENGUARD Gold, it means they failed the stricter "Gold" test, and their product would not be usable suitable for some application like around young children. A standard GREENGUARD certification is still better than nothing, but Gold is the standard for non-toxic products.
-
At the time there is no other blackout fabric that is certified by Greenguard Gold. However, if VOCs is not a concearn and you are not using the fabric around children, a regular Greenguard certification would be better than no certification.
-
Avoid Subpar Alternatives:
-
We do not suggest using coated cotton or laminated microfiber. They typically block the least amount of light and have lower insulation value as well as lower durability compared to proper blackout materials.
-
The Triple-Weave Alternative: If true 100% blackout isn't what you need, we suggest using a triple-weave polyester with GREENGUARD Gold certification. It can block up to 99% of light, has a slightly worse insulation value than true blackout fabric, but still offers great durability. We do not offer this fabric because we are working on a 100% organic triple weave room darkening curtain.
Choosing the right blackout curtain is an investment in your sleep health. Don't fall for the woven fabric trick, choose a product with certified, non-toxic, 100% light-blocking fabric.
