It is possible, therefore, to have a uniform temperature that is not steady as well as a steady temperature that is not uniform. The objective is to have the temperature both steady and uniform. Heat Source One of the first decisions to make is whether to use a centralized heating system or to use a localized heating system. Size is a consideration. Large greenhouses often can support a centralized system while small greenhouses may select a localized system.
Cost is a consideration.
Centralized systems are more expensive to install than are laocalized ones. Type of fuel may be a considration. Coal and low grade oil can not easily be burned in localized systems. Type of crop and need for soil heat may be a consideration. Centralized systems are often steam or hot water while localized systems are often hot air.