Internal plaster wall vents are generally only used for ornamentation these days, as regulations changed in Victoria in the early 1970’s changing them from mandatory to selective.
Vents were used as a system to allow air movement to reduce the amount of carbon dioxide building up in a room with an open fire and also to try to stop condensation. The problem was that most of the vents clogged up with dust over the years and became ineffective. Also with ducted heating systems they were a major problem with heat loss.
Most vents these days are installed without cutting an opening in the wall and to make them look genuine you paint an area behind the vent with black paint before installing, which will give you the effect of a hollow vent.
We use only the best materials to produce our traditionally handmade Vents, and we take great pride in the techniques we use in the manufacturing process.