Firstly BLOCKOUT or BLACKOUT can mean many things but basically refers to blocking out light or preventing heat transfer or both. Read the descriptions carefully when you purchase your curtains as there is no simple way to market them....
room darkening, it will make the room completely, or as close to completly dark. It will of course depend on the coverage you have over the window. You should aim to have at a minmum 2 times the width of fabric covering your window. For example if the window is 2m wide then the curtains should have a minimum of 4 meters of fabric. The more fabric (fuller) the curtain is the better the room darkening properties. The curtains should also overlap the window at the top and the sides. The room darkeing is achieved by the fabric having a foam coating on the reverse. This coating is made up of 3 layers. The first layer is white, a second layer is applied which is black and a final white layer. The black center layer provides the room darkeing property
has excellent thermal properties . Simply put should keep the warmth in the house during winter by providing a good barrier between the colder outside and the warmer inside preventing heat transfer. The opposite applies during the summer. 100% Blockout Curtains have an acrylic white foam coating on the reverse or on the reverse of the lining fabric if the curtains are lined, this white coating also helps to reflect the sun during the summer and prevent heat absorption into the fabric and then transferring the heat inside.
3 pass/layer foam coating
Thermal Blockout Curtains
Thermal blockout curtains are exactly that. They are designed to provide some thermal properties to your home. This means they will keep the warmth in the house during winter by providing a barrier between the colder outside and the warmer inside preventing heat transfer. The opposite applies during the summer. This is achieved in 2 ways either by having the fabric foam coated on the reverse side which will provide a thicker barrier than a plain fabric with no coating or by using a fabric that is woven in such a way that it is very thick. This type of fabric is generally referred to as a tripple weave or woven blockout. The thick fabric is what provides the barrier.
Thermal blockout Curtains generally let light into the room. They are not considered room darkening. Not everyone wants there room to be pitch black when the curtains are closed. This is a good option for longe rooms and living spaces.
Room Darkening Curtains
Room darkening curtains are just that. The darken the room when closed. Generally not 100% but some where between 90-95%. This term is generally used to describe a woven or tripple weave blockout fabric. It is a specially woven fabric with what is referred to as a tripple weave. The two outside weaves of the fabric are of the same color and the centre yarn color is black. It usually has a very simple look to the fabric, is the same color on both sides and is very soft. It does not have the faom coating on the reverse.
Room darkeing curtains are generally a heavy fabric constructions and due to the nature of the heaviness also provied good thermal properties. the negetive side to these fabric sis they dont tend to have the white reverse and the darker colors absorb the heat and provide heat transfer from inide to outside and vise versa.
The great thing about tripple weave or woven blockout is the soft drape, some people like this softness others prefr a more traditional stiffer drape. They also tend to have very good natural fire retardant properties making them good for commercial and hospitality use