In 1997 I had vinyl siding installed on my house, which is mostly brick.
The siding covers the soffit and fascia boards. When the siding was
installed, the 4x8 plywood soffit vents were removed, but the holes were
left of course. The vinyl siding has vented sections (2 ft wide) about
every 5 feet. The original plywood vents were 8-10 ft apart.

My concern is that the attic is not adequately ventilated. I'm not sure
that enough air is getting through the siding vents, then through the
plywood 4x8 holes. There is about 1/2 to 1 inch gap between siding and
original plywood soffit. I want to make sure the airflow is good enough
to ventilate the attic and help lower my energy bills.

The attic insulation is OK-I plan on adding some more.

What I am thinking about doing is removing the ventilated siding panels
(maybe not all of them), then cutting out more sections of the original
plywood soffit directly above the siding vent. Hopefully, this would allow
more airflow through the attic. The roof has 4 wind powered turbines, and I
may add 2 more.

Removing and re-installing the siding sections should not be a problem. The
house is about 2300 sq ft living area and was built in mid 70s.

I just wanted to get some opinions on whether the additional soffit vents in
the plywood would increase the attic airflow.