Very often we are asked for blackout out blinds especially from our domestic customers from around the North West. The need for black out blinds generally arises from people who work nights or for people wishing to reduce the light into childrens bedrooms. I thought I would write this brief guide to explain why the term "black out" is misleading and to help you decide if the extra money that black out blinds cost linked with the fact that they are generally made from an ugly fabric makes a purchase worth it.
Due to the very nature of a vertical blind, the blind must be fitted a couple of inches away from the window to allow the louvres to be tilted open and closed without fouling the window or window handles. Even on a recess window, when the blinds are closed you will still be left with a gap at the sides, this will be a sizeable gap if you also have a dado rail etc. At the bottom of the blind there is also a gap of around 15mm and at the top of the blind there is a similar gap between the rail and the louvres.
Further more, once the blind is closed, if viewed from an angle, because of the thickness of the weight at the bottom of each louvre a gap of a few millimetres can be seen.
Although all these gaps individually are rather small, collectively they allow a huge amount of light into the room. My experience shows that whenever a customer pays the extra for a blackout blind they are disappointed with the result.
Roller blinds are slightly better in so far as there are no louvre gaps although you still have gaps around the perimeter.
What I would suggest to our customers is that instead of paying for an ugly blackout blind, they instead choose a thick fabric. This will have a "dim out" effect and in addition to looking better than a blackout material it will cost a great deal less.
Even more good news! the more expensive fabrics are generally thin jacquard type material. Our offer fabric that we have on ebay is perhaps the thickest fabric in our range and is a relatively tight weave. We challenge you to buy it for less.
So in summary, save your money for other things, blackout blinds DO NOT do as they claim.