HOUSE HEATING 



415 



Cubical contents Sq. ft. glass 



200 



f- Lineal ft. exposed wall X2 



or 



is^6 ^o 



- 22 - +—+28 X2 = 101 . 36 sq. ft. radiation 



200 2 ° M 



The number of sections giving nearest to 100 square feet 

 should be used. For a second-floor room this can be reduced 

 by one-seventh, or to 85 square feet. This radiation is 

 ample for the coldest weather. If one is willing to shiver 

 a little on cold days, the 100 feet may be reduced to 85 and 

 the 85 to 62. 



Another formula which gives sufficient radiating surface 

 for latitudes such as southern Iowa and Illinois is as follows : 



Cubical contents Sq. ft. exposed wall Sq. ft. glass surface 

 60 10 2 



To the result obtained by the above formula add 10 per 

 cent for a room with north exposure and 1 5 per cent for one 

 with north and west exposure. 



Size of heater. Add 75 per cent to the total number of 

 square feet of radiation required for the house and buy the 



■P/nMo/e 



Air valve (radiator) 



Cross section of hot-water radiator valve 

 After University of Minnesota 



Fig. 319. Radiator valves 



heater carrying the rating nearest to this quantity. Boilers 

 are rated for zero weather, the very best fuel being used, 

 and every foot of pipe and boiler being counted as radiating 



