If you are looking for fireplaces that are Green, look no further than Direct-Vent gas appliances.  Direct-Vent gas fireplaces earn a point in The United States Green Building Council’s (USGBC) Leadership in Energy Efficient Design (LEED) program.  Direct-Vent gas fireplaces feature a solid glass front air tight design. All make up air for combustion comes from outside the home through the outer flue into the firebox chamber.  Spent flue gases are expelled outside the home through the inner flue pipe. 
Most Direct-Vent gas fireplaces are wall furnace rated as zone heaters, so not only are they decorative focal points, they are energy efficient comfort sources.  Direct-Vent gas fireplaces can be conveniently vented out the rear of the firebox, off the top and out a wall, or vertically up and out the roof or chase cavity.