balanced flue

Hey guys, I have a mid terrace property and wanted a gas fire inset, I've heard conventional chimneys can increase radon levels and wondered if any solutions exist to convert a conventional chimney into a vertical balanced flu. In my head this sounds abit impossible/ impractical but wondered...

Hello all, I currently am trying to improve the thermal efficiency and comfort level in our our 1920's end terrace. The main issue in our living room is the draught up the chimney. We currently have a high power output open gas fire. However this is useless as the draught up the chimney sucks...