I have a brick veneer home with a rectangular hole in the wall that currently holds an unneeded window air conditioner. I bought a window I would like to install there. The hole does not have a brick sill - the hole was built specifically for the AC (long before me) so there is no ledge. Lucky for me that means I won't have to cut any bricks to prepare the opening. Would a PVC exterior window sill would be the easiest way to go? Do I have to put a sill at all? I live in a VERY humid, hot area. Do you have any tips or recommendations for my project?