Blackout liners are supplements for your existing curtains, used to help keep the daylight out, reduce the level of street noise, and regulate room temperature as well as your sleep cycle. They are made with relatively thicker fabrics and have a light and dark side. Some blackout liners even have a middle-layer of foam for enhanced performance. Consider the Thermalogic Ultimate Liner if you’re in the market for a blackout liner that’s great at blocking light even without a blackout curtain. Made with 70% polyester and 30% cotton, it also blocks noise and provides thermal insulation. However, those are not the only reasons we feel this liner is the best option. It is machine-washable and dryer-friendly, meaning no cleaning hassles. You won’t have trouble putting it back either, thanks to its built-in hanging hooks. Available in three different lengths and two different colours, you can take your pick to match the curtains.