I would like opinions on the use of air deflectors on floor registers. Is it best to let air blow up on the wall or use a deflector and blow it across the floor? I’ve read both ways. Some articles say it should blow straight up and warm the walls and windows, while some say blowing it on a cold window is less efficient and it’s better to scatter the air across the floor. Or, could it be option three, which is like most things similar to this: 3. It probably doesn’t make a noticeable difference either way even though some claims it does.