Do Blockout Curtains Keep Out Heat?

Posted by Emily Wang on 6th Apr 2023

Blockout curtains have a number of benefits making them a great investment for any homeowner. One of the main benefits being their ability to block unwanted sunlight entering a space, making them an excellent choice for bedrooms and media rooms. However, when considering ways to reduce our bills associated with either heating or cooling, few of us will even consider how certain window treatments, such as blockout curtains, may help to keep our utility bills to a minimum.

The truth is that adding blockout curtains to your interior decor scheme, while a simple change, can help you to keep costs down. Blockout curtains can go by different names, such as ‘blackout curtains’, ‘thermal curtains’, ’thermal drapes’ or ‘insulated curtains’ depending on where you choose to shop. 

Blockout curtains have come along way since they were originally designed during World War II. They now come in a wide range of styles, whether you choose to shop ready-made curtains or opt for a custom look. Most blockout options can be made with an array of different fabrics and heading styles. Long gone are the days where blockout curtains are made using dark, heavy fabrics that many initially think of. 

brown blockout curtains

Thermal Layered Blockout Curtains

Blockout curtains can be produced in two ways, the first being a more traditional technique where the reverse of the fabric is foam-coated with a grey or white layer which prevents light, heat and noise being transferred from the outside world. This more traditional technique can, in some cases, give the fabric a thick, heavy look and feel that, while stylish, can be difficult to work with. These foam coated fabrics are often harder to maintain as they require dry cleaning, as opposed to being machine washable. That being said, there are some positives to this type of blockout curtain. One of which being that this type of window treatment has great thermal and light blocking qualities due to the white or grey coloured backing reflecting the light that enters through your windows. This light coloured backing can also be more pleasing to the eye from both inside and outside of the home.

Thermal Weave Blockout Curtains

The second way in which blockout curtains are produced is by choosing ‘thermal’ or ‘triple’ weave fabrics, this technique does not require a coating on the reverse of the fabric. Instead, the curtains are often made up of three woven layers. The first and last of these layers being the fabric of your choice, with the middle layer providing the ‘blockout’ properties. Triple-weave curtains tend to be a lot less structured and softer to handle when compared to those that have been coated on the reverse. Softer to the touch, triple weave blockout curtains drape beautifully and can also come in a variety of colours, patterns and heading styles. In particular, when these curtains touch the floor, this technique tends to be more environmentally-friendly.

Triple-weave blockout curtains are also machine washable, making them easier and more cost effective to properly maintain. This makes them an excellent option for children’s bedroom curtains and other high-traffic areas of the home. The reverse side of triple weave curtains is more often than not identical to the front side, making them aesthetically pleasing.

Both types of blockout curtain work by decreasing heat transferred through your windows and reflecting sunlight, therefore keeping heat out of a room. When used correctly, blockout curtains can reduce the heat transferred via windows by as much as 24%. In order to benefit most, it is recommended that you fully draw or close your blockout curtains before the sun begins to enter the room, which should ensure your room stays cooler throughout the day. You may also want to consider installing a pelmet or headboard, as well as having the curtains ‘return’ back the wall at either end. Doing so will only increase the effectiveness of your blockout curtains, which can, in turn, keep your bills to a minimum all year round.

woman looking out window with coffee

As with most essential interior products, the more you invest, the better your chosen product will likely be. If used, installed and maintained correctly, blockout curtains will stand the test of time whilst saving you big bucks in the long run. Quickfit blinds and curtains offer 5 types of blockout curtain, each with varying thermal properties. Whether to choose a triple-weave or foam coated option, each is available in an array of style and fabrications, with something to suit any interior. Our easy to follow chart will also allow you to choose a style that is guaranteed to fulfil your individual needs.

Emily Wang

Emily Wang

Emily Wang, a highly qualified expert on curtains, has been a valuable contributor to the Quickfit Blinds & Curtains brand. With a Certificate IV in Textile Design Development and Production from RMIT Melbourne, a Certificate in Textile Technology (CFTS-T) from CITA Hong Kong, and an HKDSE Diploma of Secondary Education from St. Mary's Canossian College in Hong Kong, Emily's educational background sets her apart in the world of home decor.

As a Quickfit Blinds & Curtains blog writer, Emily's curtain expertise shines through her articles, establishing her as a trusted resource for homeowners and decorators alike.