Collection: Bioethanol heater

Bioethanol Heating in a Greenhouse

A bioethanol heater burns liquid fuel with a visible flame and needs no flue, no wiring and no gas connection. That combination is why it appears in greenhouses and garden rooms where no power reaches, and where running a supply would cost more than the structure.

The fuel burns down completely. There is no soot, no ash and no residue to clear off glazing or staging, which is a genuine advantage over paraffin in a space where everything is glass.

Ventilation Is Required, Not Optional

This is the part that matters most, and it is often stated the wrong way round. A bioethanol flame consumes oxygen from the air around it and releases water vapour and carbon dioxide. In a sealed greenhouse those build up, and the space becomes unsafe to enter well before the fuel runs out.

A vent must be open while the heater is burning. Treat it the same way you would any open flame indoors: adequate fresh air, never left unattended, and never running overnight in a closed structure. The water vapour also raises humidity noticeably, which encourages mould on soft growth if the house is not ventilated.

If you need heat you can leave running unattended, a thermostatic model from the electric heater range is the appropriate choice instead.

What It Is Good At

Bioethanol suits short, attended use rather than continuous climate control. It is not thermostatic, so it burns at a fixed rate until the fuel is gone, typically several hours per fill depending on the model.

• Taking the edge off a cold evening while you are working in the house.
• Backup heat during a power cut, where an electric unit is useless.
• Sites with no mains supply, such as an allotment plot.

What it does not do is hold a minimum temperature through the night, which is what overwintering tender plants actually requires.

Placement and Safety

Site the unit on a level, non combustible surface, well clear of staging, timber, plastic covers and anything hanging. Refuel only when the burner is completely cold, because pouring bioethanol into a warm burner is the most common cause of accidents with these units.

In a polytunnel or any structure with a plastic cover, keep well clear of the skin. Polythene deforms at temperatures far below what a flame produces.

The Alternatives

For frost protection through winter, a thermostatic electric unit is more suitable and cheaper to run than fuel. The wider greenhouse heater range covers electric, paraffin and bioethanol together with output figures, so you can match a model to the volume of your house.

Insulating first is usually the better investment. Bubble sheet from the protection range lining the glazing cuts heat loss without blocking the light winter crops still need, and it reduces whatever heating you then need to run.