- Heat sources that use crops and biomass are particularly appropriate for greenhouses because farms will often have these sources of heat easily available. A corn boiler uses dried corn kernels to heat water, which is then circulated through radiators in the greenhouse. The corn is automatically fed into the boiler from a large hopper. Depending on the size of the greenhouse to be heated, appropriate corn boilers can range from tiny to enormous, with matching prices. Given the ever increasing costs of fossil fuels, owners of commercial greenhouses who heat them with oil or gas can realize substantial savings by investing in a corn boiler, reclaiming their investment in under five years.
- A wood stove heat source is appropriate for owners of small greenhouses who have access to their own wood lot. Keeping a greenhouse heated during the night with a wood stove can be labor intensive, but can also save a great deal of money, particularly if the owner cuts his own wood on his land. An airtight wood stove with a properly adjusted catalytic converter can burn through the night without requiring re-loading.
- Natural gas as a heat source is more expensive than corn or wood, but is far less labor-intensive. Practical use of natural gas is limited to people who live in areas that have access to natural gas pipelines. Natural gas heaters work in the same way as propane heaters; they burn the gas inside the heater that is located in the greenhouse and circulate the hot air through the greenhouse using fans.
- Geothermal heating requires a major outlay of cash for the original installation, but it may make sense for large operations that spend large amounts of money for heat every year. Because geothermal systems use heat that they draw from underneath the ground, the only power that is required is the electricity to run pumps and fans. Consequently, following the initial investment, geothermal is one of the least expensive methods of heating a greenhouse.
Corn Fired Boiler
Wood Stove
Natural Gas
Geothermal
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