Show heat efficiency Is determined by chimney satisfactory service of heating boller boiler or fireplace Is entirely dependent on oil tile the proper chimney this flits la Is due to the fact that the chimney Is entirely responsible for draft dm ft which Is 19 essential to supply ulf air for combustion tile chimney top should extend above the highest point of the rouf roof surrounding buildings gs or high trees must not be so near that wind currents will force air downward tile flue should run as straight as possible I 1 its outlet at the alie top should hould r not he be choked by a cup cap which might reduce the aren area of the lie opening there should be only one opening into each flue tile lining Is usually desir desirable able and Is invariably used with joints well cemented there can be little or no n impediment to the draft the av six to eight room house should hove have tin im 8 by 12 inch tile lined hue flue 15 35 feet high from basement floor door smaller holnes bild bungalows may ilmy use un an 8 by 8 lucli dinelt flue 30 feet high |