To find out that is better the weight of the dimensions considered should be compared when both gutters are filled with water.
Overall difference in water volume between 5 and 6 gutter.
With these systems a large load of water can overwhelm 5 inch troughs with their swifter flow rates.
In the past residential homes have 5 gutters and 2 x3 downspouts and commercial buildings have 6 gutters with 3 x4 downspouts.
Six inch gutter will let the leaves and other debris wash right down the downspout with no need for covers.
In this round the 6 inch gutters.
Pro s in having a 6 gutter system.
Able to handle carry more water.
For those torrential downpours 6 k style gutter can handle a larger volume of water than 5 k style gutter.
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.
Half round is also a lot more expensive than k style.
Also the steeper the pitch of the roof the more wind driven rain it will take.
It means that the gutter will not be overfilled during periods of heavy rains as there is enough space inside the gutter.
K style can handle more water than half round and a 5 k style can handle about much water as 6 half round.
Six inch troughs can hold twice as much water as 5 inch gutters.
It is important because the heavy weight of the water can cause the gutter to sag.
Now pay attention to the weight of the gutters.
Currently we are seeing more residents expand their downspouts to 3 x4 and some even install the complete 6 gutter system.