Alton Bayliss XL Roof Auto Opener

The Bayliss Clip-On Automatic Greenhouse Vent Opener is a simple, reliable solution for maintaining the ideal temperature inside your greenhouse, without constant monitoring. Designed for convenience and performance, this unit automatically opens and closes your roof vent based on temperature changes, helping protect your plants from overheating.

Built to lift up to 12 lbs (5.5 kg), this auto vent opener provides a maximum opening of approximately 12 inches, allowing consistent airflow when your greenhouse needs it most. Its compact 11-inch design and satin anodized finish deliver both durability and a clean, professional look that complements most greenhouse frames.

Features

• Wide compatibility: Fits Thermofor, Robinsons, and Alton louver vent openers.
• Restores automatic ventilation: Keeps airflow consistent and responsive to temperature changes.
• Heat-powered operation: No electricity or batteries required.
• Replacement cylinder only: No fittings or mounting hardware included.

Specifications

• Product Type: Automatic greenhouse vent opener
• Installation Style: Clip-on
• Maximum Vent Opening: Approximately 12 inches
• Maximum Lifting Capacity: 12 lbs (5.5 kg)
• Unit Length: 11 inches
• Finish: Satin anodized
• Power Source: Heat expansion, no electricity or batteries required

How it works

Automatic greenhouse vent openers are one of the most effective ways to regulate temperature and protect your plants year-round. As temperatures rise, the opener gradually lifts the vent to release excess heat. When it cools down, the vent closes automatically, helping maintain a stable growing environment day and night.