If bay windows are on your list of things to consider, here are a few reasons why you might want to put them on the “definitely, yes” side of the list. They Look Phenomenal - Bay replacement windows add visual interest to your home both inside or out. They Bring In More Light - If you have three regular windows, flat across the wall, they might bring in quite a bit of natural light. They Increase Home Value - Replacement windows in general are going to raise the value of your home. They Ventilate Well - You may not keep your windows open very often, but when you do, bay windows can really help. Read more.