What is the most cost-effective way to heat a soft-fruit glasshouse?

摘要

Given the rising interest in extending the UK soft-fruit growing season under glass, a seminar for growers keen to find out more about the economics involved was recently hosted by the AHDB. It was given by representatives of FEC Energy, which implements the AHDB-backed GrowSave energy-efficiency programme, recently expanded to cover soft fruit, with FEC senior consultant Jon Swain explaining how the heating options stack up.To get a temperature increase in the glasshouse of n°C requires energy input in watts of n x the area in square metres x 8. "That factor of eight would be just 0.45 for a house, though eight also works for heated polytunnels and is the factor used by the main glasshouse installers," said Swain. For example, to heat a hectare (10,000sq m) of glass from 5°C outdoors to 20°C indoors would require 1.2MW power — an indication of the necessary power output of the boiler. "Most boilers are rated by their output, but what it says on the tin might not be what it delivers," he warned.