The Thermal Benefits of Blackout Curtains: Do They Really Keep Heat Out?

As energy costs continue to climb, homeowners and renters alike are on the lookout for ways to reduce their heating and cooling expenses. One solution that often gets overlooked is the use of blackout curtains. Commonly recognized for their ability to block out light and reduce noise, blackout curtains also boast significant thermal benefits, helping to keep heat out during summer and retain warmth during winter. In this blog, we delve into the thermal properties of blackout curtains and explore whether they really help in maintaining a more energy-efficient home.

Understanding the Insulating Properties of Blackout Curtains

Blackout curtains are made with a thick and dense fabric designed to completely block out light. However, it’s this same construction that provides an additional layer of insulation against temperature changes. The fabric's thickness helps prevent heat exchange through windows, which are often one of the biggest sources of energy loss in a home.

During the hotter months, sunlight streaming through the windows can dramatically increase indoor temperatures, forcing air conditioners to work harder and consume more energy. Blackout curtains help by creating a barrier that reduces the amount of solar heat entering the room. Conversely, in the winter, these curtains help retain indoor heat, providing an added layer that limits the cold transfer from chilly windows, thereby easing the load on heating systems.

Black blackout curtains

Scientific Backing

Studies have shown that medium-colored draperies with white-plastic backings can reduce heat gains by up to 33%. Blackout curtains with a reflective backing are even more efficient at heat control, reflecting sunlight away from the window surface and helping to maintain a steady interior temperature.

Research conducted by the Department of Energy confirms that when installed properly, blackout curtains can reduce heat loss by up to 25%. This is achieved by creating a dead-air space between the curtain and the window, which enhances their insulative properties.

Installation Tips for Maximizing Thermal Efficiency

To reap the full benefits of blackout curtains, correct installation is crucial:

  • Ensure Complete Coverage: To effectively block out heat, the curtains should be wide enough to cover the window completely and overlap in the center.
  • Seal the Edges: Using Velcro or magnetic tapes to seal the edges of the curtains against the wall can prevent heat from escaping around the edges of the curtains.
  • Layers Matter: Using a double curtain rod to layer a blackout curtain with a lighter, decorative curtain can enhance the insulative properties by trapping air between the layers.

Comparing with Other Heat Control Options

While blackout curtains are effective at controlling heat, they are most beneficial when used in conjunction with other energy-saving strategies. For instance, exterior window fixtures like awnings or roof overhangs can provide shade, reducing the amount of heat that reaches the window. Similarly, using reflective window films can also complement the effectiveness of blackout curtains by reflecting infrared light and reducing UV light transmission.

Cost-Effectiveness and Long-Term Benefits

One of the most appealing aspects of blackout curtains is their cost-effectiveness. Compared to other window treatments or more invasive home improvements, blackout curtains are an affordable option that can be easily installed and maintained. Moreover, they are versatile and come in various styles and colors to match any interior decor.

Over time, the energy savings provided by reducing draft and solar gain can accumulate, potentially offsetting the initial cost of purchasing the curtains. Additionally, blackout curtains contribute to a more comfortable indoor environment, reducing the need for artificial lighting and helping to protect furniture and floors from sun damage.

Environmental Impact

Beyond personal cost savings, using blackout curtains aligns with broader environmental conservation efforts. By reducing the amount you depend on heating and cooling systems, you also lower your carbon footprint. This is particularly important as residential energy use is a significant contributor to global carbon emissions.


The simple addition of blackout curtains to your home can contribute significantly to thermal insulation, proving to be a practical and economical solution for enhancing energy efficiency. Whether you’re looking to keep your home cool in the summer heat or cozy during the winter, blackout curtains provide an attractive, effective way to manage your home’s climate.

To explore the range of blackout curtains that can help save energy while keeping your spaces stylish, consider the Sleepout Home Blackout Curtains. Designed to offer superior insulation, they are an excellent investment towards a comfortable and energy-efficient home.

Before and after blackout curtains

We hope this insight encourages you to consider not just the aesthetic or light-blocking qualities of blackout curtains but also their potential to improve your home’s energy management and reduce your environmental impact.

Discover More

If you’re ready to explore how blackout curtains can transform your living space, visit our product pages for detailed information and installation guides. Create a more energy-efficient home today with Sleepout!

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