I'm after some venting for my garage which I've been in the process of
sealing up in the last year so when I'm in there in winter the heat
stays in. Now i've found some things rusting in there which I assume
is because of a lack of good ventilation - so any recommendations it
needs to be able to close, be fairly large as I imagine the garage
would need reasonable airflow to stop it getting too humid and also
insulate reasonably well when closed and be burglar proof as well.

The plan is when I'm not working in there i'll open the vents - I
guess having some on each side of the garage would be best to try and
get air through the garage - it's fully detached (unlike my house LOL)