The two most common styles of downspouts found on homes are either standard 3×4″ rectangular or 4″ round downspouts. There are also commercial square downspouts available, but we will leave that for another blog post.
Choosing between the two should be relatively simple. They both carry approximately the same amount of water and the choice usually comes down to looks. Aluminum round downspouts are only nominally more expensive than the standard 3×4″ downspouts and really make your home pop!