How essential are thermal screens for an energy efficient greenhouse?

It is now well proven that retractable thermal screens can save energy without having a detrimental effect on plant growth or quality; and you might even argue that a screen is now also an essential tool for both energy saving and greenhouse environment optimisation.

Several projects have shown the huge advantages of having a screen. So why are some growers still overlooking the technology?

Obviously, if you are growing a low energy crop, or if your greenhouse does not lend itself to having a screen installed, the payback on an installation may make it uneconomic. However, paybacks on most installations are between 18 months and three years.

For example, if you are growing a crop throughout the winter months at greenhouse temperatures of 18 degrees C or more, you can expect to get savings of at least 90 kilowatt-hour per square meter (kWh/m2).

Obviously installation costs depend on the complexity of the site, but they are typically in the range of £50,000 to £90,000/Ha. This means that even with an old greenhouse with a difficult installation procedure the payback should still be no more than three years.

With this level of payback, installing a thermal screen is still more attractive than facing the difficult task of managing the installation and operation of a greenhouse with a temporary polythene screen.

Source: GrowSave / Holland Scherming