Hard coal is a solid fuel, which in itself is a clear distinction from the other three fuels, being liquids. The course and conditions of burning solid fuels differ from these, which occur during the combustion of liquid fuels. Therefore, hard coal has certain characteristics (even low maintenance requirements or limited possibilities to control the combustion process), which other fuels are deprived of.
The table lists the advantages and disadvantages of individual fuels, the list is not exhaustive.

When selecting the fuel, you should think first, whether it should be hard coal, or one of the other fuels. In the case of hard coal, you can choose a traditional boiler or use a modern quick-disconnect boiler with an automatic fuel feeder.
The use of a traditional coal-fired boiler is supported by lower investment costs (not very advanced technologies are used in this type of boilers) and lower fuel expenses. The main disadvantage, however, is the inability to use automation systems. For small boiler rooms, operated by household members, admittedly there are no personnel costs, but in larger venues, requiring employment of an employee, it may be, that the savings will be illusory, because the cost of fuel will need to be paid for servicing with derivatives.
Modern designs of low-power coal boilers have solutions that reduce service time (refilling the charcoal container is necessary once every few days). In addition, the design of the hearth (for example. retort hearth) and automatic fuel feeder (for example. screw feeder) allow to automate the operation of the boiler room. The investment cost of such a solution is, however, comparable, and even higher than the cost of a gas or oil boiler room.
By choosing to burn hard coal, however, be aware, that it is associated with the emission of a significant amount of pollutants into the environment. In the case of boiler rooms with powers above 200 kW, this means additional costs incurred on charges for discharging pollutants into the atmosphere. Smaller heat sources do not require such charges, but here it must be taken into account, whether the emission from coal combustion will not be burdensome for the owners of neighboring properties.
Generally, the use of hard coal is justified in the case of small domestic boiler houses, located outside an area with intensive development, when you want to save on investment and operating costs. However, you should be aware of this, that it is connected with the need to independently operate the boiler room. In other cases, it is advisable to use a different fuel.
Tam, where there is access to the gas network, the best solution is to design a natural gas-fired boiler house. There is no need to put up tanks for fuel and take care of its adequate supply. Besides, natural gas is still more attractive in terms of price than heating oil and LPG.
Liquefied gas and heating oil will be used in the regions, which are not connected to the gas network. If there is a possibility of connecting and using natural gas in the future, these liquid gas fired boiler houses can be easily adapted to burn natural gas.