600 Our Surroundings 



Home air conditioning is carried out on the same general prin- 

 ciple as that used in theaters. The winter air-conditioning appara- 

 tus is usually contained in a single compact cabinet. It consists 

 of a washer or filter, a coil of steam pipes for heating, and a 

 device for humidifying. The temperature of the air is controlled 

 by a thermostat, and the amount of moisture is regulated by a 

 humidistat. Thus any desired temperature or humidity may be 

 maintained automatically. The heating unit is attached to pipes 

 which lead to all rooms of the house, and the conditioned air is 

 forced through these pipes by a fan or blower. The air is drawn 

 back to the heater from openings in the rooms, thus providing a 

 gentle and continuous circulation of warm, conditioned air 

 throughout the house. The summer air conditioner is also con- 

 tained in one unit, which includes the washer, cooler, and dehu- 

 midifier. When new houses are to be air-conditioned, the spaces 

 between the outer and inner walls are often filled with an insulat- 

 ing material.' This insures a more even temperature and cuts down 

 the cost of operating the air-conditioning apparatus. 



For those who cannot afford to air condition their entire house 

 during the summer, small portable units, suitable for the air-con- 

 ditioning of one room, have been developed. These have no pipes, 

 the air of the room passing into them at the bottom and coming 

 out at the top properly conditioned. One of these units may be 

 placed in the living room and another in a warm or stuffy bed- 

 room. Or only one may be used, and transferred from one room 

 to another as needed. There are various devices for increasing 

 the humidity during the winter months in houses that are not 

 otherwise air conditioned. 



Other Uses of Air Conditioning. Air conditioning has 

 been found to increase both the efficiency and comfort of workers 

 to such an extent that many offices are now being equipped with 

 it. Stores and restaurants find that air conditioning increases 

 their business, especially in the summer. In most of these places 

 the small individual unit is used and either placed on the floor or 

 fastened to the wall. Some of these units are year-round air 

 conditioners, but most of those used are summer air conditioners 

 only. 



