One of the most important accessories you can get for your greenhouse is an efficient heater, which is essential for a greenhouse to function well. The heating needs of a greenhouse depend on its position and type of frame and obviously the requirement of the inhabitants - the plants. A greenhouse may get almost a quarter of its heat from the sun, but heating systems have to be effective enough to maintain the desired temperature 24 hours a day.
The cost and availability of the fuel and the size of greenhouse determines the type of heating system you can implement. Greenhouses can be efficiently heated with coal, electricity, gas, and oil. Kerosene may only be used as emergency heaters in small greenhouses as they emit fumes that are very harmful to plants, so pay careful attention to ventilation in these cases.
There are various type of heaters that can be used in greenhouses- space heaters, forced air heaters, electric heaters and hot water or steam heaters. The capacity of these heating equipments depends on the size of the greenhouse, its covering - single or double layer plastic or glass - and the differences in the inside-outside temperatures. In an attached greenhouse, the existing heating system of the building may be extended to the greenhouse. This depends on the capacity of the heating system and the heat requirements of the greenhouse.
Space heaters generally work on Liquid Petroleum or Natural Gas and are extensively used in greenhouses. They can be installed in the walls so that the fumes are released outwards through special vents built into the heating unit or they can be suspended overhead, so that fumes are vented outwards in accordance with the local city and county building rules.
Space heaters are more economical than forced air heaters. Forced air heaters include a forced-air furnace that distributes heat through ducts or plastic tubes. The temperature in the greenhouse is controlled and regulated by a thermostat. Such heaters are viable only for very small greenhouses.
Hot water or steam heaters work on coal or natural gas. These heaters provide a heating system that uses an automatic ventilation to maintain adequate temperatures. Electric heaters generally include overhead infrared heating equipment along with soil cable heat. This provides a localized plant environment. Electric heaters are available in various sizes and models. Some models also come equipped with fans that circulate the heat and help with air circulation. These heaters are safer options as they are designed with auto safety shut off; overheat protection and caution lights for extra security. Electric heaters are easier to install than other heating units as they involve no plumbed fuel lines and require no venting. Electric heaters are also safe and trouble free but cannot be used in large greenhouses due to high costs. Solar heaters are a more eco-friendly option but these are not very economical nor are they practical. Separate solar collection and storage systems are needed, which require a lot of space.
Each type of heater has its own plus points and drawbacks. You need to select one that is apt for your needs and which can help you pursue your gardening hobby in the best possible manner.