Right type of ventilation?

[Shea Loner]

I'm in the process of completing a viv for my little one, and I'm hoping some one has an idea about this. The viv is made of (front + back) two framed pieces of glass, the front opens and the sides are plywood.
What I'm wondering about is where would be the best place to put the ventilation? on the sides ? or screen in part of the lid. I do live in an area where the temps get pretty cold, so heat retention is a factor.
Does any one have any ideas on which you think I should use?

 

[helix321]

I too live in an area where it can get fairly cold and we keep the overall house temp around 65F in the winter - so we use a screen top that has removable plexiglass panels - the panels can be added in the winter to maintain additonal heat but removed in the summer when they're not needed to maintain temp - side ventilation is alwaysopen to ensure airflow.