We have a really wide window in our house and I wasn't sure if these would be wide enough or really do the job of blocking out light. I may need to order another set just to make it look right, but they exceed my expectations on light blocking. I took one photo with the light on and one with the light off. The sun hits that window directly, but with these curtain panels, it did not come through and darkened the room quite efficiently. ( You can see the sun through the curtains in the photo, but the sun didn't come through the curtains, heating up the room to an uncomfortable point like it did with our old so called lined curtains ) The fabric is excellent and these are incredibly easy to put up.