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Are All Blackout Curtains Thermal?

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As you browse the best curtains for the room, consider what fixes the window needs. Does the window bring too much light into the room? Does the window make the room too hot or too cold? The answers will determine what curtains you need.

Blackout curtains are a good buy, but will they cover all the window’s flaws? A specific example is “are all blackout curtains thermal?” Don’t assume that your blackout curtain will cover all imperfections. Make sure to read the item description and user reviews before buying from a supplier.

Most blackout curtains are not thermal, or insulated. Let’s learn more about the purpose of blackout curtains. And, find out what curtains you need to block unwanted heat and wind.

Are All Blackout Curtains Thermal?

Are All Blackout Curtains Thermal

Blackout curtains block sunlight from entering the room and disturbing your day. Keeping rooms dark and cool is their sole purpose. They block heat from entering the house and raising the temperature of the room. These curtains can save money on energy bills, but are not as energy efficient as thermal curtains.

Nonetheless, when the word “thermal” comes up, our mind runs to extreme winter and summer temperatures. Blackout curtains have partial thermal benefits. Not all blackout curtains have thermal benefits. After all, that’s not the blackout curtain’s purpose.

Do Blackout Curtains Provide Insulation?

Do Blackout Curtains Provide Insulation

Traditional blackout curtains provide some insulation. They trap heat into the curtain’s inner lining and stop it from entering the home. The inner lining and the outer fabric work together to reflect the heat to the window. The heat returns outside as more heat comes in, creating an invisible circle. 

This circle continues in the window area and stays there. In turn, the home maintains a cool temperature in the summer. However, curtain linings cannot handle high humidity. Thermal curtains are better for extreme winter and summer temperatures.

Expect some heat to seep in through the curtain. Although, the leakage won’t be as severe as with thin curtains, or an open window.

Do Blackout Curtains Keep Heat in During Winter?

Do Blackout Curtains Keep Heat in During Winter

The purpose of blackout curtains is to keep the room dark and cool year-round. In the winter, however, the insulation they provide keeps cold air out and keeps the room warm on the inside. It is not strong enough to seal heat indoors during winter because it doesn’t have the material to do that. The thick material has limitations on keeping heat indoors. 

A blackout curtain doesn’t have the layered construction that a thermal curtain has. When put to the test in the coldest climates, the curtains fail to keep the heat indoors. Warm air will seep outdoors, but the leak isn’t as severe as it would be with a thin curtain, or no curtain at all.

Is There a Difference Between Blackout and Thermal Curtains?

Is There a Difference Between Blackout and Thermal Curtains

There is a distinction between blackout curtains and thermal curtains. Blackouts can do some things, but as you read on, you will see that thermals can do more. 

Blackout Curtains

Blackout curtains block almost 100 percent of outdoor light from entering the room. That is due to the dual layers of tightly woven fabric within the curtain. The materials keep light from passing through the curtain. These opaque curtains stop prying eyes from outside and reduce outdoor sound. 

Blackout curtains also have protection against UV rays. Some of them may also include thermal material and have insulation benefits. 

One type of blackout curtain is called a room darkening curtain. These curtains block between 85% and 99% of light. 

Thermal Curtains

Thermal curtains block unwanted sunlight, reduce outdoor sound, and offer privacy. They also keep heat indoors during the winter by separating the indoor heat from the outdoor air. They do the same in the summer by keeping cool air inside and the hot air outside. The curtains have UV protection but cannot darken the room like a blackout curtain.

The curtains work alongside HVACs, heaters, and thermostats to regulate room temperature. While the curtains keep out the cold, you rely less on the thermostat, heater, and HVAC units to warm the house. In return, these energy-efficient curtains lower the electric bill.

Specifically, winter heat loss to the outdoors reduces by 25% compared to blackout and plain curtains. The summer heat that seeps in decreases by 33% should you use thermal curtains in the summer. 

The double or triple layering fabric method in thermal curtains matches blackout curtains. Besides the fabric, there is a thin, high-density foam layer in the center that is not found in blackout curtains. Thermal curtains have a vapor layer too for moisture and condensation issues. The heavy-duty layers block outdoor sound better than blackouts.

Which Curtains Keep in the Most Heat?

Blackout curtains are better for keeping heat outdoors during the summer. Thermal curtains are better at trapping the heat indoors during the winter. Insulated curtains keep the heat indoors in the winter and the heat outdoors in the summer. Sheer curtains are one of the worst choices for extreme winter and summer temps.

You can rotate curtains by using thermals for the autumn and winter months. In the spring and summer months, use blackout curtains. You can also combine the curtains’ benefits into one curtain to reduce rotation. There are combinations such as thermal insulated blackout curtains or thermal insulated curtains. 

Are Thermal Curtains the Same as Insulated Curtains and Blackout Curtains?

Are Thermal Curtains the Same as Insulated Curtains and Blackout Curtains

Product descriptions will market all three as the same curtain when they are not. Thermal curtains, insulated curtains, and blackout curtains achieve different goals for the room. The curtains are not the same. However, you can buy a curtain with more than one benefit if that is what you desire.

As mentioned before, thermal curtains juggle room temperatures in the winter and summer. Blackout curtains keep the room dark by blocking unwanted sunlight and glare. These curtains also protect floors and furniture from color fading and sun damage. Insulated curtains trap heat, block cold air, and reduce outside noise.


Energy-efficient or not, a window without a curtain is not wise during the summer and winter. A curtain will keep the home from being too bright, too hot, or too cold. Are all blackout curtains thermal? No, that is the goal of thermal curtains and insulated curtains.

Did you learn something new in this article? Post your experience in the comment box below. Don’t forget to share this info with people who need this information.

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