The energy savings that are made are not due to half-heated greenhouses but to sensible use of the available energy. The fan setting By using the fan setting, all the air in the greenhouse can be circulated even in the summer season. With the windows open and the fan on, the greenhouse can be cooled down. Air circulation in the summer is also necessary for the pollination of many flowers.
The fan The low power consumption of only 30watts means it can be left on for long periods without using much energy. Low-maintenance ball bearings, metal blades, a built-in thermostat, extra anti-corrosion protection and an earth wire - these are the features that make this fan a durable, long term investment. Greenhouse Heaters Explained
