I moved to a 1995 home in NC which generally heats and cools efficiently. The large family room has a cathedral ceiling and a gas log fire behind a fixed (sealed) 'glass' screen, it has a fan but this is very weak and the unit provides almost no heat and appears purely decorative. There is no proper chimney but there is a vent in the outside wall at back of the unit. Because of the high ceiling, this is a cool room in winter. Do you have any advice as to what can I do to change or replace the existing gas logs with something that gives real supplementary heat.