The question of how to warm our cottage will depend, in the first place, upon the climate and locality of the proposed dwelling, and furthermore upon its exposure. Three methods of warming the air of halls and rooms must be considered, namely, warming by open fire-places, by stoves and by hot-air furnaces. Direct and indirect heating by steam and by hot-water apparatus are excluded on account of their cost for buildings, such as here shown.
Ordinary fire-places warm principally by radiation, the heat from the fire being imparted to surrounding objects or persons without much warming the surrounding air. The degree of heat varies with the square of the distance from the grate, and it thus happens that with a fire-place as the only means of heating a room of an exposed dwelling, a person near the fire may be nearly roasted, while at the opposite extreme end of the room the temperature may be almost down to the freezing point. A further disadvantage is the fact that it heats only the part of the body facing the fire. The greatest objection to the ordinary open grate fire lies in the fact that 85 per cent. and more of the fuel is wasted, the heat from it going straight up the chimney flue. A fire-place generally causes extremely cold drafts from window cracks, or from door spaces, especially in very cold weather. On the other hand, if such cracks are all carefully closed and stopped up, the chimney is apt to smoke. While, therefore, an open fire-place may be adequate in warm climates, it is entirely inadequate to warm, per se, cottages in our eastern, northern, and northwestern States.
To say that a very large waste of fuel is incident to warming by fire-places, is not strictly correct, for the heat is not actually wasted. It forms a good aid to the ventilation of rooms, and we will see later that, as an accessory of other heating methods, the fire-place is eminently serviceable, and much to be recommended. Better, however, than ordinary fire-places, are the improved, so-called ventilating fire-places, which are provided with a large air chamber, and a sufficient air supply from outdoors. There are several excellent devices of this kind in the market, and these are, of course, much more economical as far as burning fuel is concerned, about 35 per cent. of the heat being utilized. They make splendid ventilators, and are generally superior and free from defects.
In this country stoves of cast iron and of wrought iron are the usual and most economical means of heating small cottages and suburban dwellings. It is also, unfortunately, true that, as ordinarily arranged, they make the worst possible devices for warming the air of our rooms. Heating should always be combined with ventilation, that is, there should be a continuous removal of the fouled air and introduction of plenty of pure air instead, but arranged so as not to cause inconvenient or unhealthy drafts. A room warmed by an air-tight stove must soon contain air entirely unfit to breathe, for a close stove removes practically none of the vitiated air, and there is usually an entire absence of any provision for introducing fresh air. Less fuel is consumed, and stove-heating is consequently economical, at least apparently so, while in reality it causes loss of strength, vigor and appetite, and general debility and extreme sensitiveness.
If a dwelling is to be heated by stoves, the following precautions must be observed. Select a good-sized, well-built stove, with tight joints, and lined on the inside with fire-brick to prevent the iron from getting red hot and to retain, as much as possible, the heat. A supply of fresh pure air from the outside must be arranged, carried to a jacket surrounding the stove, where the air is warmed by contact with the stove, and circulated in the room. The smoke pipe of the stove should be large, and must never have a damper to shut off the draft. A valve may be placed on the fresh-air inlet pipe to regulate the amount of ventilation at will. For the removal of foul air outlets must be arranged, near the ceiling of the room, and into the chimney, care being taken to prevent down-drafts or entrance of smoke, by arranging a self-closing flap valve at the outlet. It is much preferable, however, to have an extracting or ventilating flue, arranged in the chimney adjoining the smoke flue and warmed by the latter, with outlets from the room into such flue. The stove should have ample capacity to heat the room even in very cold weather without driving the fire to a red heat. It is a good plan to supply a moderate amount of moisture to the air by placing a water kettle or evaporating pan on the stove.
Heating suburban dwellings by hot-air furnaces has many advantages over stove heating. Furnace heating is, strictly speaking, stove heating, but with this difference, that there is only one large stove, centrally located in the basement or cellar, from which air pipes of sufficient size carry the warmed air into the rooms as desired. There is, consequently, less labor in carrying coal and making fires, less trouble in keeping up the fire, and less dirt and dust from removing ashes.
Furnace heating is disliked and has often been condemned by many as detrimental to health, and while such is true of improperly arranged furnace apparatus, it is, nevertheless, a mode of heating which can be made perfectly healthy and agreeable. It is impossible to heat a room well by furnace heat, unless arrangements are made, by an open fire-place or other outlet into a chimney flue, for withdrawal of the air once breathed and fouled by respiration. You cannot introduce pure, warmed air, unless you remove a like amount of fouled air. Another mistake, frequently made, is to take the air supply to the furnace air-chamber directly from the cellar. Thus, cellar air, ground air, or air from sewer pipes, is often sent up in a heated condition into the living and sleeping rooms.
If warming by a hot-air furnace is decided upon, care should be taken to select from the innumerable patterns in the market a good furnace. The furnace should be of the best quality of material of its kind—either cast iron, wrought iron or soap-stone,—and of a good size, for if the furnace is small, it will be overheated in extremely cold weather, which is very objectionable, as it renders the air less fit for breathing, and is liable to cause cracks in cast-iron, and loose joints in wrought-iron furnaces. The furnace must be well constructed, the pot must be lined with fire-brick to prevent the rapid burning out of the iron, the joints must be few in number and perfectly tight, and this must be made the subject of a special examination. The furnace should have one or two large cold air-ducts, leading to the outside of the house, located on opposite sides of the house if there are two. These air-ducts should take their supply preferably five or more feet above the surface of the ground. A slide-valve must be arranged in the cold-air box, to regulate the amount of incoming air, and where there is danger from impurities in the air, the air supply should be filtered through a loose cotton filter. At the mouth of the air box place a wire-netting to prevent rats or other animals from entering. The box should be constructed of well-dried, wooden plank, with closely fitted joints. Better, although more expensive, is a galvanized sheet iron air-duct. It is advisable to carry the cold-air box along the ceiling of the cellar, where it is in sight, and not below the ground, where it may and often is filled with ground water or pools of sewage from broken cellar drains. The size of the fresh-air inlet should be equal in area to the aggregate sum of all hot-air flues, leading from the air chamber into rooms. The fresh air should be kept tolerably moist by arranging an evaporating pan kept constantly full of water in the air chamber of the furnace.
The furnace must be arranged as centrally as possible, so as to make the horizontal hot-air flues short, for in these the velocity of the air current is reduced by friction, especially if the flues are small. The hot-air flues should, preferably, be kept on inside walls, and must be as direct as possible, and of ample capacity. The inlets or registers, for admitting warm air into the room, should not be in the floor, for it is unhealthy to stand over them, moreover they form receptacles of dirt and dust, and are unsightly in the floor. The inlets should be placed in a side wall. To avoid danger from charring woodwork no hot-air flues should come in direct contact with floor-joists, boards or partitions; all woodwork should be securely protected by some non-conducting material. The smoke-pipe must be large and run to a good-sized smooth flue, so as to insure a good steady draft, which will remove all gases of combustion. There should be no damper on the smoke pipe, and the fire should be regulated only by more or less admission of air under the fire grate. Overheating of the furnace must be avoided, for it unduly dries the air, and scorches the organic matter in the air coming in contact with the fire, thus causing a peculiar, disagreeable smell.