Blackout curtain vs. thermal drapes

Updated February 21, 2017

Blackout curtains and thermal drapes both save costs and energy associated with heating and cooling lost through windows. Up to one-third of a home's energy can be wasted in this way.

Primary Purpose

Blackout curtains' primary purpose is to reduce light emitted into any given room, up to 99.9 per cent of it. These curtains are particularly beneficial for those who must sleep during the day, such as night shift workers. Thermal curtains' purpose is to reduce energy lost through windows.


Blackout curtains use very tightly woven fabric, usually in multiple layers, to block light. The best thermal curtains, according to Humboldt State University's Campus Center for Appropriate Technology, also use multiple layers--a mylar vapour barrier layer plus at least one thin layer of canvas-like material.

Energy Benefits

Even though blackout curtains' purpose is not to reduce energy loss specifically, this is the result of the heavy draperies' insulative properties and light-blocking abilities. Eclipse Curtains claims its curtains can reduce heating and cooling loss by 25 per cent. Humboldt State University's Campus Center for Appropriate Technology asserts that thermal curtains reduce energy loss by increasing the insulative value of windows by as much as seven times.


Blackout curtains generally range between £9 and £26 per panel, while homemade thermal curtains generally cost between £26 and £45 per panel. Custom thermal curtains cost approximately £45 and up.

Added Benefits

Blackout and thermal curtains can not only help block light and reduce energy costs, but they can also reduce noise from the outside world.

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About the Author

Elizabeth Jennings began publishing creative works in 1988 and has been a professional editor and writer since 2002. She holds a dual Bachelor of Arts in anthropology and philosophy.