VENTILATION 



113 



Houses heated by steam or by hot water sometimes have 

 special arrangements for ventilating (Figure 44). In some 

 houses the radiators are placed in open air ducts beneath the 

 floor. The fresh air enters these ducts from outdoors, is 

 warmed as it passes the radiators, and rises through registers 

 in the floor to warm the rooms. The cold air from the out- 

 side keeps pushing the warmed air up out of the ducts and 

 flowing in to take its place. Thus a continuous circulation 

 is maintained over the radiators into the rooms. The same 

 arrangements must be made for the exit of stale, hot air as 

 are made when the hot air furnace is used. 



Many houses, however, cannot be ventilated except 

 through the windows and doors. It is most important 

 to learn how this may be done effectively. One simple 

 method is to cut a narrow board into a length that exactly 

 equals the width of the window sash. 

 Raise the lower sash, fit the board into 

 the running groove, and close the sash 

 down on it. This leaves an open space 

 between the upper and the lower sash 

 through which fresh air may enter. If 

 the upper sash be pulled down to leave 

 an opening of an inch or so at the top, 

 an exit for the stale air is provided. 



According to another method, a board 

 ten or twelve inches wide is cut just long 



. , ,1 ! * ,1 FIGURE 59. ADJUST- 



enough to reach across the inside or the ABLE VENTILATOR 

 casement. This board is placed length- 

 wise on the inside sill with its ends fastened to the sides of 

 the casement. When the lower sash is raised, the board de- 

 flects the current of cold air upward so as to prevent a direct 

 draft. In this case the opening between the sashes serves 



