Street or security lights
Look for gaps at the top and sides of the window. A curtain that does not cover the opening fully may not solve the problem.
Product-category guide
Choose blackout curtains for the light problem you actually have.
They can be useful for streetlights, early daylight or shift-work sleep. They are not a cure for sleep problems.
Start with the source
Identify where the light enters.
Early daylight
Consider the direction of the window and when the room becomes bright. A sleep mask may be simpler when travel or renting makes curtains impractical.
Indoor light
Check LEDs, chargers and hallway light before buying window coverings. The least expensive fix may be turning off or covering a small source.
Evidence and limits
A darker room is a practical environment goal.
CDC guidance recommends a bedroom that is quiet, relaxing and comfortably cool, and describes keeping the room dark as part of a sleep-friendly environment.[1] This is a general habit recommendation; it is not evidence that blackout curtains treat insomnia or any other sleep condition.
Research on light timing supports paying attention to evening and nighttime light, but the studies use varied conditions and do not test every window covering or bedroom layout.[2] For that reason, the best first step is to match the product to the specific unwanted light.
What to compare
Fit, coverage and return terms.
Look for dimensions that extend beyond the window, the mounting method, lining or stated opacity, ease of opening and the seller’s return policy. A “blackout” label alone does not tell you how it will fit your room.
Compare sleep masks as an alternative →References
Sources cited in this article
- Centers for Disease Control and Prevention. About Sleep. Accessed 19 September 2026. Read the guidance.
- Dautovich ND, Schreiber DR, Imel JL, et al. A systematic review of the amount and timing of light in association with objective and subjective sleep outcomes in community-dwelling adults. Sleep Health. 2019;5(1):31–48. doi: 10.1016/j.sleh.2018.09.006. PMID: 30670164.