Do Blackout Curtains Block Heat?

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Blackout curtains may seem like a new invention, but they’ve been around since World War Two. They were primarily used in Great Britain during the war to hide any interior light from the Nazi planes. When Nazi pilots saw a light from a particular building, the pilot was more likely to bomb that structure.

While WWII has been over for many decades, blackout curtains are still used to this day because they can block out light and have other benefits.

What Is the Main Advantage of Using Blackout Curtains?

Most people are well aware that blackout curtains block out all-natural light. While you may think the blockage is 100 percent, you must read the information from the manufacturer.

Some curtains can only block out up to 99 percent of the light. Of course, that is amazing and still worthwhile.

If you tend to work overnight and sleep during the day, you may notice that you incur sleeping problems, as well as health problems because of your strange sleeping habits. Blackout curtains give you the illusion of night, which can help prevent health issues and let you sleep and stay asleep, even when the sun blazes onward.

Blackout curtains can also help people who live in cities that never seem to sleep. The flashing lights and neon can keep you up for hours, but blackout curtains cut all that light so that you can sleep.

Along with such, people who live in northern cities may find that the sun can be out for a full 24 hours in some cases. You can use blackout curtains to create total darkness in the home so that you can get the sense of daylight and night-time.

Do Blackout Curtains Block Heat?

Of course, you want the curtains to keep light out because that is what they are designed to do. But, most homeowners want to know, “Do blackout curtains block heat?” as well. The answer is yes; they can.

Whether you choose shades or full curtains, they can reduce the amount of heat transfer from your windows into your home by up to 24 percent. Therefore, the rooms are likely to be warmer in the winter and cooler in the summer.

Blackout curtains can also help your heating or cooling system work more efficiently, thereby saving you money on your energy bills. If you have hot sunlight streaming inside the house, your air conditioner has to work doubly to keep you cool.

Do Blackout Curtains Block Heat

What Are the Types Available?

You can find a variety of blackout curtains, such as roll-down blackout shades. These products have a plain design and are inexpensive.

You can find many sizes, which allows you to fit them to your windows. Then, you can just pull them down all the way and not have to worry about sunlight or heat.

Blackout liners are also available, and they have the added benefit of working in conjunction with your current window treatment. They shut out the sunlight and warmth, but they also protect the existing curtains in your home.

If you want the full-on benefits of blackout curtains, you should buy them directly. You can find a variety of lengths and sizes available, so it is best if you measure your windows and determine what you need. You need to ensure that you get the right dimensions since if there is a part of the window uncovered by the curtain, you won’t get the full blackout effect.

You can also make blackout curtains yourself. Sewing isn’t that hard. If you don’t care how the finished result looks, you can do it yourself to save money.

You can purchase blackout fabric like a knit or woven fabric in multiple prints and colors. The material can be light in color, but the foam or rubber is what blocks the light and heat.

How Are They Used?

You can hang the curtains over any window to completely cover it. You can still open the window for airflow during the cooler part of the day. Most of the time, blackout curtains have a built-in white liner, which should be positioned toward the glass so that it reflects more sunlight from the space.

While not a significant concern for everyone, you may find that the HOA has no issue with this because most of these associations require that you have cream or white window dressings anyway. They won’t see what’s on the inside, so it doesn’t matter that you have designs because these won’t show through to the outside.

While blackout curtains work better if hung outside the window, it isn’t likely that your HOA or neighbors will like that. Along with such, you run the risk of them being stolen.

The blackout curtains should be closed before the sun comes up. Otherwise, the room is already starting to heat up and you’re still defeating the heat in the house.


Before making such a significant decision to buy blackout curtains, it is essential to know what they can and cannot do. Most people use them to block out light, but they can block out heat, as well. You can save money on the electricity bill and have a more comfortable house.

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