You can really add a special touch or flair to your home or yard by installing glass block windows. They are a cost effective solution for replacement basement windows and will lower your costs for maintenance, however there are a few draw backs.
Block Windows Don't Open
A big issue with using glass block windows is that once they are installed, you can not open them to let in air or to ventilate the space they are installed in.
Loss of Visibility
When you look out or a pedestrian passing your home, looks in through the glass block windows, it will be impossible to distinguish what is happening on the other side of the glass. These windows are a bubbled glass, that distorts light and images on either side of them, cutting off your view to the outside world in any distinguishable manor.
Modern glass block windows can be very cost efficient as once they are installed, they create an air tight seal preventing effects on your homes inside air from the outdoor temperature changes. They in effect work very much like double pane windows in this way, as the center of them is an air pocket or chamber.
Regular maintenance that is required for standard basement window designs, such as aluminum framed units, is not required for glass block windows. They are nearly maintenance free once installed properly.