126 



THE PRODUCTION AND USE OF HEAT 



is made clear. It will be noted that floor registers are used 

 for the first floor rooms and all wall registers for the second 

 floor rooms. In some houses each room on the second floor 

 is provided with a flue for the return of cold air to the furnace, 



if INSIDE CIRCULATION is 



the system to be used. 

 These are not often pro- 

 vided, however. A good 

 circulation is secured by 

 permitting the cold air to 

 return down the stairway 

 (see plans, Figs. 92, 93 

 and 94). 



144. A Successful Fur- 

 nace. To be a success, 

 the furnace should be so 

 constructed and so set as 

 to accomplish the follow- 

 ing results: 



1. There should be a 

 large volume of moder- 

 ately heated air passing 

 through the furnace and 

 into the rooms to be 



heated at all times. A small volume of highly heated air is 

 not only uncomfortable but unhealthful as well. 



2. There should be no cross-currents of air. The cold air 

 from all parts of the house should join in a single current when 

 returning to the furnace. (Study Figs. 93 and 94.) 



3. The heated air should enter at the warmest portion of 

 the room and the cold air should be drawn out from the coldest 

 portion. 



4. All of the air in all of the rooms to be heated should be 

 in constant circulation, and all of the air should be heated to a 

 comfortable temperature. 



5. A successful furnace does not overheat the basement. 



/?00 



FIG. 94. Second floor plan for setting a 

 furnace. 



