Popular Science Monthly/Volume 30/December 1886/How to Warm our Houses
By E. Y. ROBBINS.
IF a blizzard of unusual severity were coming from the northwest that would send the thermometer down 50° or 70° in three hours, we should expect a great increase of pneumonia and other respiratory diseases, resulting in many deaths. Now, instead of three hours, suppose the mercury were to drop threescore degrees in three minutes—or take another step in fancy, and suppose this great change to take place in three seconds—what would likely be the effect on health? And yet we bring about, artificially, changes to ourselves quite as sudden and as severe as this.
We make an artificial climate in our houses. We live in-doors in an atmosphere heated by stoves, furnaces, or steam-pipes, to 70° or 80°; and we pass from our parlor or hall so heated into the open air. At a step, literally in a breath, the temperature of the air has, for us, dropped 50° or 70°. We may put on an extra coat or shawl and shield the outside of the body and chest, but we can not shield the delicate linings and membranes of the air-passages, the bronchial tubes, the lung-cells. Naked, they receive the full force of the change—the last breath at 70°, the next at freezing or zero—and all unprepared. We have been sitting, perhaps for hours, in a tropical atmosphere; nay, worse, in an atmosphere deprived by hot iron surfaces of its ozone and natural refreshing and bracing qualities. Our lungs are all relaxed, debilitated, unstrung; and in this condition the cold air strikes them perhaps 60° below what they are graduated to and prepared for. Is it strange if pneumonia and bronchitis are at hand?
If we are in the West Indies, or even in Florida, and wish to come North in winter, we try to make the change gradual. But in our houses we keep up a tropical climate, or worse, for you have not the freshness of air that prevails in an open tropical atmosphere, and we step at once into an atmosphere as much colder as 40° difference of latitude will make it. It is in effect going from Cuba to Iceland—or at least to New York—at a step, and we make the journey perhaps a dozen times a day. And often, while we are still shut up in our domiciliary Cuban climate, Iceland comes down upon us from an open window. Especially is this likely to occur in school-houses, where children will instinctively seek to get a breath of fresh air that has not had all its natural refreshing qualities quite cooked out of it by hot stoves, furnaces, or steam-pipes. And all these sudden changes and shocks of cold come upon us while the whole system has its vitality and powers of resistance gauged down to the low necessities of a tropical climate.
And what should we expect as the effect upon the health—upon the respiratory organs? What are the facts? Pneumonia has increased nearly threefold in New York, in proportion to the population, within the last fifty years; and, if we had separate records for that class who most use the hot-air arrangements, we probably would find a much greater increase.
Bronchitis, which is also getting to be a very prevalent and fatal disease, has increased even more rapidly than pneumonia, and now causes about fifteen hundred deaths in New York city every year, being an increase of nearly fivefold to the population in fifty years. What is the cause? We have a sufficient and a very obvious cause, in the fact that in our methods of heating our houses we have been "progressing backward." Fifty years ago there were few furnaces or close stoves, and no steam-pipes, for warming; houses were warmed by open fires. The difference is radical and of great importance.
It may be briefly explained thus: Radiant heat from the sun or from an open fire passes through the air (so far as it is pure air) without warming it; that is to say, without being obstructed or retained by it (just as light does), and only warms the pavement, floor, walls, or other opaque body on which it falls. Hence, on a sunny day the pavement will be at 100°, while the air above it is only 50°. The air that touches the iron bars or the surface of the fire in an open grate goes to feed the fire, and then is drawn up the chimney. Only pure, radiant heat is thrown into the room, not hot air; and it does not heat the air at all directly, but warms our bodies, the walls, furniture, etc.
Recently we have thrown this aside, and, instead, put a surface of hot iron in the room or in the cellar, in the form of stove or furnace, or steam-pipes, or hot-water pipes, against which the air itself is heated by convection or contact, and by its consequent lightness rises into the room and to the ceiling.
By the first method—open radiation—we warm our bodies, walls, floor, furniture; by the second we heat the air. By the first method all the heat the air gets it gets from floor, walls, and furniture. By the second, all the heat the floor, walls, and furniture get they get from the air, the process being exactly the reverse. The difference is radical and great.
By radiation from sun or open fire we get a quick, active heat, that travels nearly 200,000 miles in a second. By convection, or hot air from iron surfaces, we have a comparatively dead or dormant heat that moves only a few feet in the same time. By radiation from open fires the air is the coolest thing in the room; by the air-heating method it is the hottest. By open fires the lungs get less heat than any other part of us, and so are braced and strengthened; by the hot-air process they get more heat than any other part, because the hottest air rises uppermost about the head, and so is inhaled, making the lungs tender and sensitive to cold on our going out. Put a thermometer at the floor, and another at the ceiling, in a room heated by the hot-air process, and you will find the air at the ceiling from 15° to 45° warmer than at the floor. And so the head is surrounded by a torrid atmosphere, while the feet may be cold.
We want to warm our bodies, not the air. Cool air is denser, contains more oxygen, and warms the blood more than hot air, besides refreshing and strengthening the lungs, and bracing them against injury on going out. We want air with a normal amount of ozone. We get it with the ozone all destroyed by the hot-iron surfaces. The Professor of Chemistry in the London University (Dr. Graham, a very high authority) says ozone is destroyed at 140°.
Suppose the top of your house removed, and the sun shining freely down into it in winter. Your floor, walls, furniture, and your clothing, will have a temperature of, say, 100°, while the air itself will be only at 50° or 60°. An open fire is a miniature sun, and its radiation is governed by the same laws as that of its great prototype. With an open fire put in proper position in your room, while your walls and floor will be at about 80° or 90°, the air will be at 50°. Replace this open fire by an air-heating arrangement, and your floor and walls will be found to be only 50°, more or less, while the air rises from your close stove or your hot-air register at from 140° to 250°. If you doubt it, put a thermometer in your register, and see.
What do we want of such air as this? Evidently nothing, and so kind Nature sends it upward as quickly as possible, to get it beyond our reach; but we defeat her beneficent intent by closing the ventilators at the ceiling; and so after cooling somewhat it descends, still far too warm (and robbed of all its ozone, and the refreshing qualities of natural air), to enfeeble the lungs, and render them susceptible of injury on going into the external air.
The only remedy for all these mischievous conditions and effects is entirely to abandon the plan of applying the heat to the air—of making the air the carrier of heat. Heat wants no carrier, any more than light. It can outfly Mercury "and the swift-winged couriers of the air." Put your fire in proper position; take away the iron and brick casings that inclose it and obstruct its natural movements, and, quicker than you can think, the heat will be flashed all over your room; darting out in straight lines in every direction from the surface of the fire—down, up, and horizontally; and this without expense for pipes or hot-air ducts. If one grate is not enough, put another on the opposite side of your room. Coals are cheaper than coffins; and wood is better used to keep the body alive than to inclose it when dead.
An almost perfect arrangement for warming a room would be an open fire, and the entire surface of the walls and ceiling formed of a reflecting material. Then the least possible fire would warm us, because the heat would be kept alive, active, radiant; being reflected constantly from side to side, and up to ceiling and back, as quick as lightning-flashes; and so, impinging upon the body on all sides, would give it a lively, glowing warmth, while the air might be at almost any lower temperature. It would be like having a fire on every side of the room. Of course, this could not, in practice, be perfectly carried out, but it might easily be carried out approximately. Common tin plate is said to reflect eighty-eight per cent of the rays of heat that strike it. This might be stamped with some pleasant design, impressing it very slightly, to break up any distorted reflection of images. Possibly wall-paper might be made with a figured metallic reflecting surface. For a school-house this would be a great improvement, as it would reflect the light as well as heat from every side, and so prevent distorted positions of sitting, which are often found to prevail where the light is only on one side of the pupils.
With the heat of an open fire radiating or reflected upon our bodies, we should not want so warm an atmosphere by 20° or 30° as we do when all the heat in the air. And so the air would be fresh and invigorating, and the lungs would be braced up and strengthened to resist any shock from inhaling the external air. Of course, we must be comfortable. "We must not suppose that suffering with cold is good for health. But we want just as little warmth of air as is consistent with comfort; and we want the heat free from the air, and of an active character. As long as we make our school-houses and dwellings hot-houses, or rather hot-air houses, we must expect to see our children grow up hot-air productions, liable to be withered by exposure, and blasted by pneumonia and consumption.
Some places among the high Alps have recently become famous as winter health resorts. Dr. Wise, in a book recently published in London, descriptive of some of these places, says that at Davos, a point in the Alps five thousand feet high, and surrounded by still higher snow-covered mountains, invalids can remain in the open air, even when it is 15° or 20° below the freezing-point, simply by the warmth of solar radiation and the reflection of the sun's rays from the surrounding snow-crystals. He says that the reflection of the sunbeams from the surface of the snow is so strong that ladies who carry parasols over their heads, and so preserve their complexion from the influence of the direct rays of the sun, nevertheless become tanned ("burnt" is the word he uses) by the reflected rays from the snow below and around them. Altogether it is something like a great room, half a mile wide, with mountain-walls covered with snow, two or three thousand feet high, and floor of snow; open above, with the sun's rays pouring down, and the heat being reflected from every side and from below, by a million million snow-crystals, warming the bodies of the invalids; while the mountain-walls keep off the winds, and the quiet air is perhaps 10° or 20° below freezing.
This is Nature's sanitarium (though the picture may be a little overdrawn above the reality), and such a sanitarium, in miniature, we may have in every house, and in every school and college, if we will, by discarding our present abominable air-heating arrangements, and using, instead, open fires, in proper positions and at proper elevations for obtaining the best results (either with or without reflecting walls), and with ceilings of perforated tin plate, for the double purpose of reflection and ventilation. We want no little, inefficient, pepperbox ventilators, nor an air-supply that will send a perceptible current of cold air upon one side of us. The perforated, metallic ceiling might be stamped with appropriate artistic designs, which the light would bring out and make pleasant to the eye. In public halls this might be beautifully and appropriately carried out by an artist of good taste. In any case the reflecting surface must be made of the proper material, as some substances (a common looking-glass, for instance) reflect light from an open fire, but not the heat, well.
In a large room several grates on different sides would be required, and to obtain the best results they should be set at somewhat different altitude and in different position from the ordinary setting. Indeed, they may be made to give out double the heat they usually give. The front surface of a fire is the main efficient heating surface. Hence the grate should be made several bars higher in front than common, and if it is set higher up in the wall than usual and inclined forward at the top, it will be found to radiate downward and warm the floor much more effectually. But all these improvements in the shape, position, and setting of the grates can be easily come at by a little practice and philosophy. The main thing to be done is to quit the use of debilitating hot air, and warm the body by radiant heat, giving the lungs cool, refreshing, bracing air to breathe. It is a most important matter. Money can not measure the value that such a change in our method of warming houses and schools would be to the nation. We would be healthier and happier, and in the course of generations would have appreciably and measurably more perfect physical forms, more active brains, clearer minds, and better morals—better morals, I say, if for no other reason than that of our obeying the laws of Nature, which are the laws of God.