By connecting several buildings to the same heating system the number of heating generation systems is reduced to one. This usually saves investment costs. Additionally there is in general a smaller total peak load than the sum of all separate peak loads by the included buildings. Not all buildings will need their peak load at the same time. On the other hand the heat distribution system, large pipes in the ground, will generate additional investment costs and additional thermal losses. In many cases local district heating systems and district heating systems include waste heat (e.g. from the generation of electricity) or renewable heat.