When considering expanding your grow space there are a thousand things to consider. We’re going to tackle five different solutions. As we know, energy costs are a large drain on the profit margin, but there are other options to consider instead of, “that’s how we’ve always done it.” For example, at Laughing Stock Farm, in Freeport, Maine, the owners have switched their heat source to cooking oil from local restaurants. The restaurants give the oil away because otherwise they have to pay to have it removed. Great idea, right?
Store excess heat:
Excess heat may be stored in water tanks. A good image for this application is by taking a look at areas by large bodies of water, i.e. oceans and lakes. These areas tend to have a more moderate temperature. This application is executed by using a primary boiler system on optimum efficiency 24 hours a day. The excess heat during the day is stored in a large water tank that, during the night, helps heat your greenhouse. An inexpensive way is to have large tanks of water stored under plants that will soak up the excess heat and release it during the night, cutting heating costs at the same time.
While storing excess heat is a green idea, upgrading to a Delta-T system is the new black. This heating system won’t heat the whole house, rather just where the plants need it, at the roots. This may be uncomfortable for employees, but that’s what jackets are made for. When using root heat plants are healthier and it increases crop production while saving you 20-30% in energy with a more efficient use of that energy.
Reduce air leaks:
Some growers opt to use infrared sensors to find air leaks. An inexpensive way is to visually inspect glazings, walls, doors, fans, vents, and other areas where the covering material attaches to said areas. Patching holes, weather stripping doors, fan openings, vents, and ensuring that louvers are lubricated properly to close tightly are great seasonal checks. You could even shut off some exhaust fans from late fall to early spring, and cover them with insulation or plastic to reduce the air flow in the greenhouse.
Double poly to Polycarbonate:
While having two layers of poly in a greenhouse is a great saver, upgrading to rigid twin or triple walled panels made from polycarbonate or acrylic plastics is a significant saver. The advantages of the polycarbonate are found in the life span of the material. While double poly needs replaced every four years or so, the polycarbonate lasts up to 15 years. The savings here are up to 50% by switching. Pretty impressive.
Retractable curtains are becoming a popular installation in greenhouses. In a gutter connected greenhouse, for example, they are installed inside above the trusses. These create shading for crops from spring to fall and in the winter months, they block heat from escaping to the top of the greenhouse and eventually outside. Growers who use retractable curtains have reported a 30% energy savings.