Greenhouse Heaters

Greenhouse Heaters

Extend the growing season in your greenhouse or polytunnel

During the winter, temperatures become too cold in the UK for most plants to grow. In colder weather, heating is vital for the survival of plants, fruits, and vegeatables. A greenhouse heater prevents frost, damage, and creates ideal growing conditions during colder months. It extends your growing season. It encourages healthy growth and provides more opportunities.

Whether you are a hobbyist with a small outhouse or a farmer with a larger greenhouse, polytunnels or growing sheds, we can provide suitable heaters.

How to heat a glasshouse

You can do many things to your greenhouse, polytunnel or growing shed to help it keep heat.

Insulation is a key aspect. A poorly insulated structure will not keep heat well. As a result, any heat provided by a space heater will escape, wasting energy and money.

You can create heat sinks in small greenhouses using plastic containers of water. The water will absorb heat through the day and release it back into the greenhouse.

Hotbeds can also retain and release heat. A hotbed is a raised bed filled with layers of decomposing straw, manure and other organic matter, topped by a thinner layer of growing medium (soil/compost). You can place plants or seeds in the hotbed to keep them warm. But the key benefit is that as the organic materials in the hotbed break down, they give off heat.

You can place rocks around the edges of your greenhouse. A rock structure will absorb heat through the day and then radiate the heat into the space.

All these methods will help gather and retain some heat within a greenhouse. However, these methods are more suited to smaller hobbyist houses and sheds rather than large commercial spaces. A space heater will also be required to generate the heat needed to keep your plants warm and healthy during the winter months.

What kind of heater is best for a greenhouse?

Three of the most popular heaters for greenhouses and polytunnels are electric, gas and paraffin heaters.

Electric

Electric fan heaters provide a fast, simple and convenient method of heating. The Elite EHFH electric fan heater has thermostat control, so it will switch on and off as required to maintain the required temperature. In addition, the warm air these units produce is clean and safe in enclosed spaces so you can use them in greenhouses and polytunnels with no ventilation.

Electric heaters are often cheap to buy, but they are more expensive to run over a longer period. Our range includes compact 240v electric fan heaters for small spaces and domestic use, large 400v industrial electric fan heaters for commercial and industrial use, and areas with a 3-phase power supply.

Gas

Propane heaters are often the cheapest hothouse heaters to run. Some gas space heaters feature an internal fan to distribute the warm air, such as the Master BLP 33, so you need to plug them in. Other smaller propane heaters don't need electricity at all. You can use them in growing spaces without electricity, such as the Eden 2kW gas heater. Some models feature a built-in thermostat so that you can control the temperature in the area.

It is best to use a greenhouse gas heater in a space with some ventilation to prevent a build-up of fumes produced during the combustion process. Although the CO2 emitted is beneficial to plants, it is best to maintain a safe level. Specialist units such as the Eden & Eden Pro feature oxygen depletion sensors which shut the unit down if oxygen levels in the space are depleted. This is great for safety but could mean that the heater shuts down during the night in a space without adequate ventilation.

The cold can affect the performance of butane. At around -0.4°C (31.28 °F), its vaporisation slows, making it unusable. If where you live tends to reach freezing temperatures in the winter, you might consider using propane instead. Alternatively, keeping a small electric heater near to bring the temperature up first can work.

Paraffin

Specialist small paraffin greenhouse heaters are available, ideal for hobbyists with a small space to heat. However, indirect oil-fired space heaters such as the Master BV77 offer an excellent solution for heating large commercial greenhouses and polytunnels. These heaters can be fuelled using diesel, paraffin or kerosene, and they blow out only clean, fume-free warm air so that you can use them for heating enclosed spaces safely.

Indirect heaters are designed to sit outside the space, and the heat is vented through a hole in the wall using flexible ducting. Fumes produced during combustion are expelled outside via a flue on top of the heater.

Indirect space heaters can also be set up inside the space, with the flue set up to vent fumes outside through the roof. They are available in a wide range of sizes, and they offer large volumes of warm air to heat large spaces effectively. They can operate using a remote thermostat to control the greenhouse's climate automatically.