What you need to know about ventilating a greenhouse

The importance of healthy air

As you probably know, a greenhouse effect is created within a greenhouse. UV rays heat the glass of a greenhouse, generating heat inside. This heat rises from the bottom up but is retained within the glass structure. The result: an optimal climate for plants and flowers.

Or is it? While retaining heat in a greenhouse is important, plants, just like us, need oxygen to survive. Furthermore, excessively high temperatures can be very harmful. That is why it is important to create a good airflow and to ventilate your greenhouse properly.

How to ventilate a greenhouse

In the first instance, you must ensure that air (and heat) can escape from the greenhouse. Since heat rises, roof windows are the perfect solution. The number of roof windows you choose depends on the size of your greenhouse. The more you install, the better.

Secondly, you should create an airflow from the outside in to supply fresh air to the greenhouse. This can be achieved by:

opening a door;

installing a louvre window;

providing an additional sliding door.

Manual or automatic window?

Both roof windows and louvre windows are available in manual and automatic versions.

Regarding roof windows, manual models are the most common. These windows are opened and closed by hand. Manual roof windows located higher in the roof are often equipped with a spindle (screw mechanism).

Gardeners who have automatic roof windows would not want to be without them. They are extremely convenient and, contrary to what you might expect, not expensive at all. The windows operate using oil in a cylinder, so they require no electricity or solar energy.

Automatic roof windows are adjusted to the temperature inside the greenhouse. As soon as the temperature reaches a certain level, the windows open and later close again. This means you no longer have to worry about them and can leave your home with peace of mind.

What warranties do I have?

You benefit from the following warranty periods:

10 years on the quality and alloy of the aluminium
10 years on the paint finish (powder coating) in case of delamination, peeling, flaking, corrosion, chalking, discolouration and loss of gloss where the pre-defined tolerances are exceeded, in accordance with the Qualicoat or Qualinod specifications
10 years on the adhesion and tension of the glazing rubbers
10 years on production defects in the glass
5 years on PVC components and their UV resistance

The following damage is not covered by the warranty:

Damage caused by failure to follow the installation and operating instructions
Damage resulting from use other than the intended normal use
Damage due to lack of maintenance
Normal wear and tear
Materials and items used at the customer’s specific request
Structures not part of the Janssens range but manufactured at the express request of the customer or distributor

Our greenhouses are intended for growing vegetables, fruit, flowers, etc. The following characteristics are inherent and vary depending on the situation, environment and use:

Condensation on glass or profiles
Draughts at doors, windows or gaps
Roof windows, roof connections and gutters are not 100% watertight
No waterproof barrier beneath the foundation frame

What you need to know about ventilating a greenhouse

The importance of healthy air

How to ventilate a greenhouse

Manual or automatic window?

Frequently Asked Questions

Do you have any questions?

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