In the study in which the cost of geothermal energy is determined in terms of required heat energy, fuel quantity, carbon dioxide emission values and competitiveness if the internal temperature is kept constant at 18 °C in the greenhouses with different characteristic features in Antalya province, which has a Mediterranean climate and is heavily used for greenhouses in our country, and in Kırşehir province, which has a continental climate and the greenhouse cultivation has been developing. The maximum heat power requirement if the temperature inside the greenhouse is kept constant at 18 °C was determined as 253 W m-2 for Kırşehir province and as 141 W m-2 for Antalya province. In addition, the required heat energy requirement during the production period was calculated as 589.02 kWh m-2 year-1 for Kırşehir province and as 219.06 kWh m-2 year-1 for Antalya province if the single-layer PE plastic which is widely used in our country is used without heat protection measures. When the double-layer PE plastic and well-insulated heat curtains are used, these values were determined as 304.09 kWh m-2 year-1 for Kırşehir province and as 103.35 kWh m-2 year-1 for Antalya province.