Hot water systems are either centralized or localized. The size of the boiler unit, the fuel source, size of the operation, and maintenance costs all must be considered when deciding which one to use. Both systems utilize perimeter piping or under benches.

Central heating systems generally distribute heat as either steam or hot water. Hot water is produced in a central boiler and is usually pumped through the greenhouse.

Localised systems are located within the structure that they are designed to heat. These systems typically will not have the Btu generation capacity of a central boiler, and different types of localized heating systems will utilize different types of fuels.