Installation of Valor G4 direct vent gas insert into 1960's masonry fireplace in basement. Basement fireplace would not draw (as many do not) because of negative pressure issues. Cost to make this a working open-face fireplace was actually greater than installing a highly efficient insert. The customer's children who played in the basement but were always chilly in the winter months were gathered in the room to play by the time we left. There was no hint of a chill in the room on a very cold night.