Top-swing windows are outward opening and fully reversible. Whilst both opening and closing the widow there is a multi-step hinge restrictor which needs to be operated. This is a safety feature which is particularly useful if there are small children in the vicinity.
The size of openable parts (sashes) is restricted to a maximum size of 1500mm wide and 1500mm high, with a semi-perimeter of 2700mm.
Being reversible, cleaning the outside of the windows from inside is very simple. Also, suitably sized windows will provide a means of escape in the case of fire.