Bayliss MK7 Triple Spring Auto Vent Opener

Well made! The holes did not align with the old ones so new ones had to be drilled to fit the new vent openers, but this is to be expected. The vents work great and if the quality is the same as the old ones that I replaced, then it will be another twenty years before I have to do it again!!! Very satisfied!!!

Our first opener worked so well, we purchased a 2nd one--our greenhouse has two wooden gable windows on each end and we needed some additional airflow. Both of them work well. We like that they were very easy to install and can be adjusted to open sooner or later (depending upon the temperature). Initially we were a bit concerned if our windows would be too heavy for the opener, but this hasn't been an issue.

I purchased the heavy duty Bayliss Autovent MK7 with triple springs to replace a light duty Autovent in the roof of my greenhouse. The push rod became bent during a severe wind storm. The triple spring MK7 was a perfect fit 10-minute replacement. I highly recommend the Bayliss Autovent. Except for the one wind-damaged vent, mine have been trouble free for three years.

I have the orchid wax model. With the setting knob all the way in, it doesn't begin to open until the internal temp in the greenhouse reaches 85 degrees. Other than that it performs as advertised.

I placed this unit in my greenhouse on a side window to create better cross ventilation. I already have two of the same vent openers that operate the ridge vents on the greenhouse and they have been working flawlessly for the last years. I will admit to trying to save a buck and previously installing a "lesser brand" of opener on the side window. It did not make it a year before failing.
I went back to the tried and true and am happy I did so.
I very much recommend this vent opener.