13. Thermostatic valves come with some boilers to cut off automatically and “set on” heat. This conserves fuel. (See section on heat control.) PIPING The piping from boilers to radiators has to be done carefully. The best steam fitter is none too good. The grade or pitch of the pipes etc., the area of surface, the diameter _et al_ must be adapted to area to be heated and to the system employed--all of course, is too technical for your needs here. Only you must require care to be used here and let your contractor know you’re “on.” THE GAS BOILER In this boiler you get maximum comfort and maximum heat. No coal, no ashes, no bother, little cash. But this must be from the best makers. It is usually more costly to operate--but--! WATER BACKS Boiler makers in outstanding manufacturers make excellent water heaters in which water for laundry etc. is heated by heat which would otherwise be unused. RADIATORS Radiators are the translators! They are like the English writers who translate the Russian novel. The radiator alone tells us whether our hot water in the boiler is being translated into heat for our comfort. They are either curses or benefits! But they are usually the eye-sore of the home. In short they are a series of tubing which present a maximum of heat radiator surface. They have valves, for controlling the heat. If you buy the right valves, your radiators will not leak, water-hammer or bang, or flood. An air valve must let out the _air_ to permit the steam or water to fill the pipes. If it doesn’t do this, it is of no use. Varying steam pressure, flooded radiators, forced firing of boiler (which you must avoid by having a boiler with large enough capacity) are overcome with correct valves. The right valve saves fuel, because unnecessary amount of pressure is not needed to force out air, the right valve copes with dirt and dust, prevents floods, requires no adjustment. Air and steam units cannot mix, the valve releases the air. The valves must be all metal five years guarantee, and no adjustment necessary. The radiator which is recessed in the wall has the advantage of being less visible, but unless you employ heat reflectors you will lose a lot of heat--and even with them you lose some. Some manufacturers are doing their super-level best to build radiators which are lovely to the eye. But, again like the upright piano, they can be made but comparatively beautiful. Gratings can veil them but are gratings lovely? Then too, there is a loss of heat. One radiator company has good-looking radiators which are very successful. Their series of columns make them able to resist high internal pressure. The internal area of the tubes in relation to the heating surface has been reduced to ¹⁄₄ of that run in general use. This not only greatly increases the pressure resistance but in reducing the internal area, the water or steam contents are likewise reduced.