What climate factors most impact greenhouse energy costs?
Written by
Benjamin Miller
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.Energy costs associated with the greenhouse environment stem from heating, cooling, humidity control, and lighting systems, which are used to create and maintain the optimum environment for plants. Heating will be the largest energy cost incurred in the wintertime. Cooling costs increase as the summer months roll in. Humidity control and supplemental lighting will contribute to operating expenses on a year-round basis, affecting the final price, depending on the climate, growing regimen, and type of crop grown.
Heating Systems
- Consumes 40-60% of total energy in temperate climates
- Geothermal systems reduce costs by 50-70% long-term
- Thermal curtains prevent 30% nighttime heat loss
- Zoned heating targets specific crop needs efficiently
Cooling Requirements
- Evaporative cooling uses 25-40% summer energy
- High-pressure fog systems optimize water-to-cooling efficiency
- Shade screens block 70% solar heat gain
- Natural ventilation reduces mechanical cooling needs
Humidity Control
- Dehumidifiers consume 20-30% annual energy
- Ventilation systems manage moisture but waste heated/cooled air
- Vapor pressure deficit optimization minimizes energy use
- Heat recovery units capture energy from exhaust air
The biggest energy expense during the cold months involves heating. Conventional heating systems consume a significant amount of fuel, whereas geothermal heating provides a consistent temperature. Insulation improvements, such as double-poly coverings and thermal draperies, cut heat loss from 30 to 50 percent. Controlling heating zones leads to more efficient energy use.
Cooling systems are responsible for a large part of the summer energy peaks. Evaporative cooling is most effective in hot, dry climates, but requires large amounts of water. However, high-pressure fogging with controlled droplet size uses little water and provides maximum cooling. Shade screens, which block from 30 to 80 percent of the sunlight, provide significant relief in cooling loads during peak, hotter periods.
Maintaining humidity control requires continuous energy, regardless of seasonal fluctuations. Dehumidifiers remove moisture but use energy. Managing vapor pressure deficit can decrease dehumidification. Heat recovery systems capture the energy from the dehumidification exhaust air and can save 20-40% of humidity control costs.
Lighting supplementation has different energy impacts depending on the area. Northern climates require more artificial light in the winter months. LEDs use 40% to 60% less power to run than HPS lights and produce less heat. Automated dimming systems adjust the lighting according to the availability of natural sunlight.
Strategic integration of these systems is the most effective way to achieve maximum efficiency. Combine geothermal heating with thermal storage. Use shade screens in conjunction with natural ventilation methods to enhance comfort and reduce energy consumption. Automate controls to shift high-energy-use operations to off-peak hour operations. This approach typically results in a 30-50% reduction in total energy use.
Read the full article: Greenhouse Climate Control: Growth & Efficiency
