Ventilation windows can freeze shut at temperatures around the freezing point
Vents freeze partly due to radiation and the insulating effect of the screens, which is the case during night frost.
Vents freeze partly due to radiation and the insulating effect of the screens, which is the case during night frost. With multiple screens and greenhouses being increasingly closed off, it is often colder above the top screen. The rubber seal of the vents freezes to the aluminium greenhouse frame. “Every year, business owners open vents without realising they are frozen shut,” Theo Herngreen, a greenhouse technical specialist, explains. “The temperature difference between the greenhouse air and the windows is considerable, and temperature sensors or separate measuring boxes are not always installed above the screen. Opening the vents while frozen damages the rubber seals, or worse: the vent mechanism and window actuators can be deformed or broken.”
Vents freeze partly due to radiation and the insulating effect of the screens, which is the case during night frost. With multiple screens and greenhouses being increasingly closed off, it is often colder above the top screen. The rubber seal of the vents freezes to the aluminium greenhouse frame. “Every year, business owners open vents without realising they are frozen shut,” Theo Herngreen, a greenhouse technical specialist, explains. “The temperature difference between the greenhouse air and the windows is considerable, and temperature sensors or separate measuring boxes are not always installed above the screen. Opening the vents while frozen damages the rubber seals, or worse: the vent mechanism and window actuators can be deformed or broken.” The result: severe damage and delayed production If the vents are frozen to the greenhouse frame, the vent mechanism may be deformed, and the window actuators may be broken. This renders the entire vent mechanism unusable, and vents can no longer be opened. If the vents are broken, vegetables (e.g. tomatoes) cannot be harvested for six weeks for food safety reasons, resulting in severe damage. It will take a few weeks to repair the actuators and vent mechanism. Ordering materials and disassembling and assembling everything takes time, during which it is difficult to control the greenhouse climate. The solution is simple: measure the temperature above the screen The outside temperature is not a save threshold to determine whether it's safe to open the windows. Despite an outside temperature above zero, windows can still be stuck. An extra temperature sensor above the curtains provides you extensive insight into the deck temperature and will help you know when you can safely open the vents. When this sensor shows a temperature of 4 °C, it is safe to open. We are happy to help It is important to know that you are not alone. Your insurance broker is happy to give you advice to help you prepare for a harsh winter as well as possible.