5. Regulation, control, and flexibility

The effect of type of heating system on regulation and control of air temperatures throughout the house, as well as on the flexibility and responsiveness of the system, is often given too little consideration. Certain systems may be controlled from a central point, such as the main heating unit, far better than others. Stoves, of course, which are individual units in themselves and must be dealt with separately, are hardly to be considered in this connection.

Unless a direct steam heating system is specially equipped, as with vacuum air valves at each radiator, and the entire system is made air tight, it will not be possible to regulate the temperature of the steam and control house temperatures from the main unit. The ordinary steam system is "all on" or "all off," and it will generally overheat in mild weather, unless especially equipped with manual or automatic regulation of the drafts to actually operate under vacuum conditions. Hence, the ordinary direct steam heating system has little flexibility.

A direct hot-water heating system, on the other hand, as well as an indirect warm-air heating system, is extremely flexible and the house temperature may be controlled from the main unit by manual or automatic regulation of the drafts. In mild weather, very low water or air temperatures may be maintained, and in severe weather very much higher water or air temperatures corresponding to the weather conditions may be maintained. So long as there is any fire in the main unit there is heat in the hot water radiators, or in the air entering at the registers. The warm-air furnace system is the most responsive of all systems, as a change in fire intensity in the main unit is immediately reflected in the temperature of the air passing through the system.

6. Operation and maintenance

With hand-fired systems using solid fuels, there is not much difference in the attendance required in operation where a single central heating unit is installed in the home. Stoves, of course, require much more attendance depending upon the number installed and in operation.

Mechanical coal stokers, which are now available and quite successful, will materially reduce the amount of attendance required for any type of heating system. Oil burning and gas burning equipment still further reduces the amount of attendance, but the latter can only be considered where a gas service is available. Special attention is directed to the fact that when mechanical stokers, oil burners, and gas-fired equipment are once installed, the operation of an entire system is dependent on the reliability of the electric service usually essential in all such systems.

The maintenance of any heating system depends largely on the care and attention given to the system and varies through wide limits. No system is absolutely foolproof, but a warm-air furnace system is practically immune against freezing which, of course, is not true of steam and hot-water systems. The fuel burning unit of any heating plant may be ruined in a comparatively short time by careless firing and indifferent control of drafts.

An exactly similar unit and type of heating system may last a lifetime if carefully fired and properly regulated, so that the fire is never allowed to "run away" with drafts left wide open. Uniformity of operation, meaning a fairly constant house temperature day and night, means long life for the main unit, and more comfort for the occupants, and generally requires less fuel.

Throwing the drafts wide open and then allowing the plant to "run wild" every morning is about as perfect an illustration of "what not to do" with a heating plant as could possibly be found.

7. Installation and operation costs

Selecting the type of heating system on the basis of installation cost alone may result in disappointment. In general direct hot-water systems cost more to install than indirect warm-air furnace heating systems with direct steam systems somewhere in between. The range in cost of materials and labor for any one of the three systems is probably greater than the difference between the cost of any two successive systems listed above.

The range in cost just referred to has no reference to quality of materials and labor, but to the differences in design and installation details which may exist with any one type of system. The "best" of any one type of system, including all automatic devices for regulation and control, may cost much more than the "poorest" of some other type of system with no automatic devices for regulation and control.

Operating costs do not vary greatly in the same house between the three systems, provided the same fuel is used and the same degree of automatic or manual control is provided, and we have a well-designed plant in each case. Small differences in the overall efficiency of the heating plant as a whole are of no great consequence since the only heat really lost from the house is that left in the smoke gases at the top of the chimney, assuming an inside chimney. Of course, if there is much difference in the completeness with which a given fuel is burned, the efficiency of the main unit becomes important.

In conclusion, it seems hardly necessary to add that the selection of the "best" type of heating is not a simple matter, but depends on many factors, the relative importance of which varies with the individual homeowner, his house, and its location.