---
product_id: 48480807
title: "MK7 Automatic Vent Opener"
brand: "bayliss"
price: "€ 81.11"
currency: EUR
in_stock: true
reviews_count: 8
category: "Bayliss"
url: https://www.desertcart.ie/products/48480807-mk7-automatic-vent-opener
store_origin: IE
region: Ireland
---

# Adjustable 12°-25°C activation Wax expansion piston tech Temp-triggered auto-opening MK7 Automatic Vent Opener

**Brand:** bayliss
**Price:** € 81.11
**Availability:** ✅ In Stock

## Summary

> 🌿 Keep your greenhouse cool, calm, and collected—automatically!

## Quick Answers

- **What is this?** MK7 Automatic Vent Opener by bayliss
- **How much does it cost?** € 81.11 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.ie](https://www.desertcart.ie/products/48480807-mk7-automatic-vent-opener)

## Best For

- bayliss enthusiasts

## Why This Product

- Trusted bayliss brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Complete Installation Kit:** Includes all fixings and clear instructions for quick, hassle-free setup so you can start optimizing your greenhouse environment immediately.
- • **Silent & Smooth Operation:** Wax expansion mechanism combined with piston and spring system delivers quiet, reliable vent movement—no noisy motors or electricity required.
- • **Durable & Versatile Design:** Satin anodised finish with stainless steel springs, compatible with both aluminium and wooden greenhouses up to 26 lbs per window.
- • **Effortless Climate Control:** Automatically opens greenhouse vents as temperatures rise, maintaining optimal growing conditions without manual intervention.
- • **Precision Temperature Activation:** Customizable opening threshold between 12°C and 25°C ensures your plants get perfect ventilation exactly when needed.

## Overview

The Bayliss MK7 Automatic Vent Opener is a smart, wax-driven device designed to automatically open greenhouse roof windows up to 76cm x 76cm and 26 lbs as temperatures rise. Its adjustable activation range (12°-25°C) and durable stainless steel springs ensure reliable, silent ventilation for aluminium or wooden greenhouses, helping maintain stable growing conditions without manual effort.

## Description

Product description Automatic ventilation give stable temperatures. You need a quarter of the floor area in opening vents. Wax operated Vent Openers, the hotter it gets the wider they open. Designed to open your greenhouse window automatically. It works by a wax within the cylinder of the opener expanding when it is hot, pushing a piston to open the window, when it is cool, it contracts and stainless steel springs close the window. It is suitable for aluminium or wooden greenhouses and is supplied complete with easy to follow instructions for simple installation Adjustable to start opening anywhere between 12° - 25°C. Supplied with full fixing kit and instructions. Supplied in a satin anodised finnish Safety Warning Ensure to install and use the product carefully, keeping fingers and other body parts away from moving parts to avoid injury.

Review: A good quality product. - I found the Bayliss Mk 7 to be a very well designed and manufactured product which does its job efficiently and without fuss for a reasonable price. The two I purchased were fairly easy to fit but I did have to manufacture my own aluminium brackets as the ones supplied were too flimsy for use on my wooden conservatory roof windows, which are the maximum designed weight for the product. In use the units are easy to adjust but I did find that the bearings 'cracked' from time to time when in motion and so I lubricated them sparingly with some drops of silicone grease (the kind used to assemble '0' rings into plastic pipework) hoping that this will not adversely affect the nylon in the bearings - it certainly cured the problem and they have now worked well for the first six months. I would expect them to last for many years to come.
Review: Maintains a good temperature - Works really well

## Features

- Suitable for opening greenhouse roof windows 76cm x 76cm weighing up to 26lbs
- Designed to open the window automatically when temperatures increase
- Works by wax within the cylinder of the opener expanding when it's hot, pushing a piston to open the window
- When it's cool the wax contracts and stainless steel springs close the window.
- Suitable for aluminium or wooden greenhouses

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B002EIMRH0 |
| Best Sellers Rank | 28,866 in Garden ( See Top 100 in Garden ) 172 in Greenhouses |
| Customer Reviews | 4.3 4.3 out of 5 stars (138) |
| Date First Available | 24 Jun. 2009 |
| Item model number | MK7 |
| Manufacturer | Bayliss |
| Number of doors | 1 |
| Number of vents | 1 |
| Package Dimensions | 40.8 x 9.8 x 8.4 cm; 580.6 g |
| Part number | MK7 |

## Product Details

- **Brand:** Bayliss
- **Colour:** silver
- **Cover material:** Plastic
- **Frame material:** Aluminium
- **Item weight:** 581 g

## Images

![MK7 Automatic Vent Opener - Image 1](https://m.media-amazon.com/images/I/51+o0w7kRML.jpg)
![MK7 Automatic Vent Opener - Image 2](https://m.media-amazon.com/images/I/91G+0E6z2HL.jpg)

## Questions & Answers

**Q: Will this product be suitable for an aluminium greenhouse fitted with a polycarbonate pane? I believe many automatic openers are unsuitable.**
A: It should be fine, presuming your polycarbonate panel is fixed securely inside an aluminium frame / surround as the opener bolts to the frame. The spring loaded mechanism rests against the window pane when closed, but should not exert any pressure onto it.

**Q: Mines wound all the way out and its still opening too early, any advise**
A: I am unable to help you with this problem. Has it just started doing this or has been an ongoing problem?

## Customer Reviews

### ⭐⭐⭐⭐⭐ A good quality product.
*by J***N on 14 January 2010*

I found the Bayliss Mk 7 to be a very well designed and manufactured product which does its job efficiently and without fuss for a reasonable price. The two I purchased were fairly easy to fit but I did have to manufacture my own aluminium brackets as the ones supplied were too flimsy for use on my wooden conservatory roof windows, which are the maximum designed weight for the product. In use the units are easy to adjust but I did find that the bearings 'cracked' from time to time when in motion and so I lubricated them sparingly with some drops of silicone grease (the kind used to assemble '0' rings into plastic pipework) hoping that this will not adversely affect the nylon in the bearings - it certainly cured the problem and they have now worked well for the first six months. I would expect them to last for many years to come.

### ⭐⭐⭐⭐⭐ Maintains a good temperature
*by R***S on 1 June 2025*

Works really well

### ⭐⭐⭐⭐⭐ strong and good quality
*by W***L on 6 April 2025*

High quality auto opener. The MK 7 model I bought fitted the existing attachments on my greenhouse and slotted into place easily.

## Frequently Bought Together

- Bayliss MK7 Automatic Vent Opener
- Brannan Max Min Thermometer and Hygrometer - Ideal Greenhouse Thermometer and Humidity Meter To Monitor Maximum and Minimum Temperatures and Humidity Easily Wall Mounted
- 15-Pack Greenhouse Bolts and Rings, Aluminium Cropped Head Greenhouse Bolts and Nuts, Creating Suspension Anchors Point In Glazed Steel Channels to Plant Clips for Climbing Plants, Building Greenhouse

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*Product available on Desertcart Ireland*
*Store origin: IE*
*Last updated: 2026-01-29*