Paul Barker said:I thought it didn't have to be ducted as long as you are satisfied that there is suitable route to outside.
Pass on that.
The only reference I could find in BS 5440-1 & 2 is ducted. Of course a room or space under the floor is not a lot different from above, so your probably right.
I would sooner see it through the wall above the skirting if there is a suitable wall.
Bl00dy regs