Soffit Vents

[CanoeBoy]

I Had a ridge vent put on the roof this earlier this summer on my ranch house.  I'm questioning if I have enough venting in my soffit and what is the  proper way to add more.  I presently have soffit vents spaced every 4ft.  The vents are of aluminum material that match the siding done way before I lived here.  I don't think I will be able to match the color of the siding to replace the entire soffits, so I was thinking about adding 8 X 16 vents I saw at Big Box store.  Is this a cheesey way of doing it, and how do I know if I have enough venting.  My location is Soutern WI.  Thoughts and opinions appreciated.

Thanks ,

Mike

[K. L. McReynolds]

Basically, intake/exhaust(soffit/ridge vent)areas for attic ventilation need 1 square foot of ventilation for every 300 square feet of attic floor area.

That square foot is divided between the soffit and ridge areas.

Handy calculator