Our new house has an open loft, looking down to the living room. I know from experience that the electric bills are killers with this open plan and it is a guest quarters anyway so I don't want to have heat and a.c. all of the time. Since it will be used a few hours a day I thought to close it in but wanted the light--windows! Now I need to know who makes interior windows. I saw them on a photo here but they were custom by an arch. firm. Can you buy them ready made?