Greenhouse heaters are heating appliances tailored for use in a greenhouse environment. There is a huge range of types of greenhouse heater available to buyers, which can be matched with the size and heating requirements of the greenhouse in which the heater is to be located.
Paraffin Greenhouse Heaters
The most popular form of greenhouse heater is the paraffin greenhouse heater. Paraffin greenhouse heaters are generally cheap to run, as paraffin is inexpensive and easily obtained. They operate via a wick and burner system, whereby a wick directs the paraffin upwards towards a flame where it is burned, producing heat. The burner itself is housed in a cylindrical stainless steel enclosure around which is a perforated surface. This allows the heat to be distributed evenly in all directions using the process known as convection. Many commercial greenhouses that use other greenhouse heaters will also have a paraffin greenhouse heater on hand to act as a backup, as no external power outlet is required in case of power outages. A downside of this type of greenhouse heater is the fact that burning paraffin produces large quantities of water vapour, which can cause problems in sensitive greenhouse environments. On the plus side however, they also produce CO2 gas, which is important for plants.
Electric Greenhouse Heaters
Electric greenhouse heaters are also commonly seen being used in both small and large greenhouses. Electric greenhouse heaters are extremely cost-effective, and more environmentally friendly than gas greenhouse heaters and paraffin greenhouse heaters. Electric greenhouse heaters work by using heating elements to heat the air, which is then circulated around the greenhouse by an in-built fan. Electric greenhouse heaters with thermostat controls can be controlled much more accurately than the controls on paraffin greenhouse heaters, which makes them ideal for sensitive growing situations, and some are fitted with controls which only switch on the electric greenhouse heater when the temperature falls below a predetermined level.
Gas Greenhouse Heaters
Gas greenhouse heaters (also known as propane greenhouse heaters) are also available, but are generally less common than electric greenhouse heaters and paraffin greenhouse heaters. A gas greenhouse heater works by burning propane gas to generate heat, and so could be a cost-effective option for those with sufficient supplies of propane. The waste gasses and other by-products caused from burning the gas could be problematic in sensitive growing conditions, however.
Solar Greenhouse Heaters
A more environmentally conscious form of greenhouse heater is the solar greenhouse heater, although a solar greenhouse heater may have much greater initial expenditure than other systems. These systems operate by using solar collectors on the greenhouse to use solar energy to heat water, which is then pumped into a radiator system which heats the greenhouse. These types of system are not widely used as solar greenhouse heaters are not considered economical, although they are becoming more popular with green organisations.
Most types of greenhouse heater are fitted with safety devices that turn off the device if it is knocked over or tilted below a certain angle. Larger models are fitted with fuel gauges, in the case of gas greenhouse heaters, or digital thermostats, in the case of electric greenhouse heaters.