Some have a cabinet fan which draws in and exhausts both from the front,
>so don't need any additional cabinet ventilation.
>Some are convection cooled and need a heat exhaust up the back of the >cabinet.
Ours has the cooling fan that blows out the front but the manufacturer's instructions also asked for ventilation holes above and below the (built-in) oven. That said, I have never felt any draught coming from the ventilation holes I cut in the cupboard. HTH