My GH reached above 122 and those from Rion weren't ruined. The first ones that came with the GH were already defective but those they replaced them with worked fine on the hottest days. All the paper that came with them said was not to let them freeze. With temps of 60F at night, that wont happen.

I have two Bayless MK7 vent openers and two Univent. All have worked flawlessly for 4 years, even in high temp. summer conditions.

greenhouser and cuestaroble, thanks for the input. I'll check on the units that you've suggested.

Using the solar units is a lot simplier than running wires to a motorized unit, if I could locate one.

We get freezing temperatures a few days a year, but if it gets down to freezing in the GH, I've got bigger problems than venter openers.

Thanks again.

Pick up an inexpensive electric heater at Wal*Mart or some other cheapo store. It's worth the peace of mind to know you wont find your favorite plants frozen to death some winter morning.

I use an automatic heat activated, roof vent mechanism from Lee Valley. It is made in England and of excellent quality. It operates at 120+* in my GH.

The website picture shows it being used on a wall window but I use it on a small window installed in the roof of my GH, near the ridge line.

Here is a link that might be useful: Lee Valley Heat Activated Window Opener

The problem likely wasn't the heat, it was the fact that they were the HF brand. DH bought me the HF openers not knowing I had read they are garbage and one failed within 90 days or less, I can't remember and the other only worked to open the vent part way.

I live in Portland OR where heat is not a problem.

buyorsell888,

I think you may be on to sometime with respect to the quality of HF vent openers, particularly given the success that other folks have had with units not-HF. At the time the price seemed right.

Thanks to you and the others for your input.

Dennyg

I bought the OptiVent opener from Charley's. It wasn't ridiculously expensive (appx $50), and it definitely seems to work.

...Even when temps topped 100* - I think 120* was the max - and the Optivent performed just fine.

I did end up removing the vent opener after a few weeks, however. During my "Ventilation Experimentation" I determined that I wasn't getting enough cross-ventilation w/the vents open. I had to open a panel on the opposite end of the GH and vent out the top/front in order to get the proper air-flow. At least that was my experience..

As they say, "YMMV," but I can honestly say that I was pleased w/how the Optivent performed....

HTH

-Nancy

P.S. Link to my website, below, has photos of the Optivent. Also check out the Solar Fan page which covers my "Ad-Vent-ures in Ventilation" - maybe you'll find it useful. Maybe not!!! Maybe your eyes will glaze over because I tend to "yack" alot!!! ;-)

Here is a link that might be useful: Greenhouse Saga

The LVR vent system is expensive, but very heavy duty. I hope that helps.

Here is a link that might be useful: Automatic Vent Openers