Many thanks for your enquiry regarding the suitability of heating equipment for your greenhouse. For a structure of the size you have indicated, we would recommend the Tropic Electric Fan Heater GHE-001. This heater has two settings, 1kw and 2kw and will comfortably generate the heat output you require.
We would always recommend a fan heater over a tubular heater where the growing of plants is involved, as the fan is able to distribute the heat generated more evenly around the greenhouse and is thermostatically controlled. The tubular heaters are ideal for sheds, garages and workshops where the heater can be switched on and off manually, but can create localised hot spots in a greenhouse as the heat is not dispersed.
It is also advisable to insulate your greenhouse, whatever the age and condition, with bubble insulation as this can save up to 30% on heating costs. We are able to supply tri-laminated, UV stabilised Bubble insulation GHE-014 and the assorted alliplug fixings, spacers and corner adaptors for this purpose.
Hopefully this information is of help and if you have any further questions or queries, or more detailed information on this rather complex of subjects, please do not hesitate to contact us.
Many thanks for your enquiry and we hope to be of service to you in the future.