Gas — a very popular heating system. Natural gas burns in the boiler, and all harmful substances are excreted through the hobby. Modern boilers have a high efficiency of useful action, automation supports the desired combustion mode. But this method is acceptable only in the places where the gas pipes were extended. Unfortunately, in many Russian villages and small cities they do not know what “blue” fuel is and continue to toss firewood into the stove in the stove in the oldest.