Greenhouse Ventilation

About Our Greenhouse Ventilation 🌬️

Proper greenhouse ventilation prevents overheating, controls humidity, and creates the ideal growing environment your plants need year-round. Our collection includes automatic roof vent openers, manual louvre vents, replacement wax cylinders, and complete ventilation systems from Britain's most trusted manufacturers including Bayliss, Elite, and Vitavia.

The secret to effective ventilation lies in creating natural airflow through convection—the chimney effect. Hot air rises and escapes through roof vents, while cooler fresh air enters low through louvre vents. This continuous cycle maintains optimal temperature and humidity without electricity costs. All our ventilation products qualify for free UK delivery and come with a 1-year warranty, with most orders dispatched within 5 days.

The Chimney Effect: How to Choose & Position Your Vents

Frequently Asked Questions about Greenhouse Ventilation

• How many vents does an 8x6 greenhouse need?

  An 8x6ft greenhouse (48 sq ft) needs approximately 9.6 sq ft of ventilation following the 20% rule. This typically means 2-3 automatic roof vents plus two louvre vents positioned low on opposite sides to create effective cross-ventilation through natural convection.

• Why does my greenhouse get condensation even with vents open?

  Condensation forms when humid air contacts cold glass surfaces. During winter, crack vents slightly overnight to allow moisture to escape while minimizing heat loss. Position louvres low to bring in drier outside air, and ensure roof vents vent humid air at the highest point where moisture naturally rises.

• Can I add extra ventilation to my existing greenhouse?

  Yes, you can retrofit additional vents safely. For glass greenhouses, replacing a pane with a louvre vent requires specialized glass cutting tools and new glazing clips. Aluminium-framed greenhouses like Elite or Vitavia models have specific retrofit kits. Contact us on 0800 098 8877 for model-specific compatibility advice.

• Do automatic vent openers work in winter?

  Automatic wax cylinder openers function in winter but require careful management. The cylinders respond to temperature, not season. During frost, many gardeners remove cylinders temporarily and manually control ventilation to prevent spring-loaded vents from opening during cold snaps, which would waste precious heat.

• What's the difference between louvre vents and roof vents?

  Roof vents are single-pane openings installed at ridge height that allow hot air to escape. Louvre vents feature multiple angled glass or polycarbonate blades that open simultaneously, positioned low to admit cooler air. Together, they create the chimney effect—cool air enters low, hot air exits high—providing the most effective natural ventilation.

• How often should I replace autovent wax cylinders?

  Replacement wax cylinders typically last 3-5 years with proper care. Signs of failure include oil leaks, sluggish operation, or vents not opening at normal temperatures (15–25°C trigger range). Quality cylinders from Bayliss or original manufacturer replacements for Elite and Vitavia models offer the longest service life.