The ProBuilder 54 Linear features 54” wide by 15” tall glass and is a perfect economical choice for zone heating mid-size to larger entertaining spaces up to 1,650 square feet. This GreenSmart^® Basic (GSB) model conserves fuel with a GreenSmart^® pilot system that automatically lights the fireplace when heat is called for, and turns off the fireplace when no heat is needed, making for an excellent energy-efficient fireplace.