As late as 1926 a review of the heating industry for the previous fifty years, published in a prominent American architectural journal, had not • one word to say about tubular radiation, light-weight brass and copper radiators, viscous-fluid air filters or present-day methods of concealing radiators and humidifying the home. All of these advances have come with astonishing rapidity.

To get a clear idea of the development of the industry it should be stated that the progress since the World War, both in the design and application of heating appliances, outweighs that of the entire previous period.

Warm-air furnace heating, as we know, held the field for many years before steam or water heating was even thought of. But the success of radiator heat in some of the larger buildings in the centers of population soon began to stir the imagination of the more affluent home-owners and in the late '70's we begin to hear of occasional installations of steam and water heating systems in homes.

For years steam and hot water ran neck and neck in popular favor. As better methods of steam heating were adopted the hot-water people, not to be outdone, developed methods for accelerating the flow of the water and thereby secured an added efficiency for water heating which has enabled this method to hold its own in the face of the growing competition of vapor heating. To-day vapor steam heating has gained such favor as to be accepted as standard in many sections of the country.

1 Adapted from "Heating Steps Forward," American Builder and Building Age (formerly Building Age), April, 1929.

In radiator-heated houses one seldom sees a radiator on an inside wall and yet from the earliest days to the present time warm-air furnace systems have continued to be installed with registers so located as to preclude any possibility of satisfactory heating. Since the advent of the auxiliary warm-air furnace fan, installed in the furnace casing at the cold-air inlet, there has opened a brand new field of usefulness for the warm-air furnace. With the increased air pressure supplied by the fan it now is possible to locate the registers in their proper places near the outside walls and thus counteract the cold-air currents before, rather than after, they enter the room.

Perhaps the most significant feature of the advance in heating methods and, perhaps, the underlying cause of the new era, is the realization that a house-heating system can be made one of the home's most attractive features, instead of a necessary evil in the economy of life. No doubt this is due in part to the advent of the oil burner, but not entirely. Much of the credit for the improved status of radiator heating belongs to the lightweight heating surface of copper and brass and their alloys which has made it possible to conceal the radiation, within narrow limits. For the first time we saw heating surface, only a fraction of the size of cast-iron radiators, concealed in partitions and in outside walls in such a way as to provide fully as much heat as the larger units.

It is not too much to say that the new arrangement made possible by concealed radiation transformed the whole picture of home heating. It lent itself so readily to architectural treatment that the design of the heating system has come to rank second only to the design of the house itself. In places where exposed radiation is still necessary we have the graceful tubular radiator at our disposal.

More recently there has come the development of still another type of radiator designed to throw more heat out into the room and less toward the ceiling, thereby securing equal effect where heat is most needed, while actually condensing less steam. This heating surface is set flush with the wall and secures its effect largely through its radiant heat. Its advocates speak of it as the herald of the "era of useful heat."

When the oil burner reached its present state of development and the gas burner, as well as the gas-fired boiler, established their places in the house-heating field, they not only helped to usher in the era of heating comfort, but they did an unexpected thing in freeing the basement from its lowly place as a storeroom for coal and the endless array of household impedimenta. Thereafter, the basement was able to assume a new role as a playroom for the children or a billiard or a lounge room for the older members of the family.

While methods of heat regulation were fairly well known to the industry before domestic oil burners became so popular, it is a fact that the rise of such devices in systems using both oil and gas for fuel led the way to the wide adoption of thermostatic control and other devices in the home.

[Note. - Several makes of automatic stokers are on the market. Usually the fuel which is placed in a hopper is carried to the under side of the grate by a conveyer where it is pushed up through the center. The conveyer usually operates by an electric motor. A draft is provided by a blower. The burning of the fuel starts from the top and goes downward.]