Pro s in having a 6 gutter system.
Overall difference in water volume between 5 and 6 gutter.
Six inch gutter will let the leaves and other debris wash right down the downspout with no need for covers.
In the past residential homes have 5 gutters and 2 x3 downspouts and commercial buildings have 6 gutters with 3 x4 downspouts.
Now pay attention to the weight of the gutters.
K style can handle more water than half round and a 5 k style can handle about much water as 6 half round.
Half round is also a lot more expensive than k style.
Six inch troughs can hold twice as much water as 5 inch gutters.
For those torrential downpours 6 k style gutter can handle a larger volume of water than 5 k style gutter.
Also the steeper the pitch of the roof the more wind driven rain it will take.
The difference is about 50 of the amount of water treated by the 5 inch gutter.
But even among k style aluminum there is a wide range of choices mostly regarding thickness which ranges from 019 to 032 but also on finishes.
This further decreases the chance for overflow of your gutter even during the hardest of windblown downpours.
A larger gutter actually will hold more debris than a standard five inch gutter and is not self cleaning.
In this round the 6 inch gutters.
Able to handle carry more water.
If you want the best performance from your gutters and have a larger roof area then 6 gutters along with the larger 3 x 4 leaders downspouts are able to handle approximately 50 more water than a regular 5 gutter.
To find out that is better the weight of the dimensions considered should be compared when both gutters are filled with water.
Currently we are seeing more residents expand their downspouts to 3 x4 and some even install the complete 6 gutter system.