Greenhouse Univent Window Opener

So far, so good! I attached it to a wood frame on a cattle panel greenhouse. I had to figure out how to mount it so it would work with my window setup, but I got that done. Since it was hot outside when I installed it, I left the cylinder in my cooler house. Once it was installed it didn't take much time to start opening the window. Now I have to see how it functions so that I can adjust it for warmer temps. I will keep an eye on it, since the cylinder that came with it was dated "2019", so that is a 7-yr old cylinder. Overall, as of installation yesterday, mid-April, it is doing its job, as expected.

Good quality. It's interesting to see it open and close on its own as the temperature changes. I like that doesn't require any external input to do its job. I did have a few issues in high wind with it coming undone at the bottom where it's intended to be removable. It wasn't damaged, and just popped back in.

Not yours, your seedlings'. If you're getting your first coldframe or a simple greenhouse, you really need an automatic vent opener. Unless you are in your garden religiously every day, there will come that unexpected warm, sunny day early in the season when you'll forget to prop up the lid on the cold frame. You'll come home to find all your lovely, tender seedlings, with all their promise of bursting youth and color, lying limp and toasted and very dead all across your six-paks. Six weeks of careful tending and happy anticipation ruined in a moment. Some gardeners never recover. So save yourself the heartache and get an automatic vent opener. I've used the Univents and they are very dependable. They work off the temperature of the air, which causes the oil in the black cylindrical cartridge to expand and push forward the piston-rod in the cartridge. No electricity, no wires, very simple, very little to go wrong. Installing one can be confusing to figure out, mostly because they are designed to work with so many different possible vent configurations, but some staring at the (small) drawings for awhile will provide necessary clues. Once you understand what goes where, the actual installation is pretty easy. One other nice thing about the Standard Univent is that you can easily unhook it from its lower bracket (the one on the coldframe wall), so you can swing the lid up completely free and have full access to the interior. Very quick. I haven't used any other kind of auto vent opener so can't make any comparisons, but the Univents have been very reliable.

I bought two of these units, and they worked great for about six weeks, then failed. The "t" bracket at the end of the piston plunger mounts into holes on the 2 main brackets. After the holes were drilled, there was less than 1/8" of aluminum left on the sides of the brackets to give the bracket strength. After 6 weeks of wind vibration, this bracket wore through, and both brackets broke at this stress point, making the whole unit useless. Also, all the aluminum brackets on the device are held together with aluminum rivets, so there are potentially 4 different points where these brackets can fail due to vibration. I repaired this device by drilling out all rivets and replacing them with stainless bolts and lock nuts and cut two pieces of 1 1/2 inch wide aluminum stock, (at a 45 degree angle) about 4 inches long, and bolted them to the broken angle brackets with 6/32 x 3/4 inch bolts with lock nuts. I re-drilled the hole for the "t" bracket in the new stock, and now the unit will hold the stress and vibrations of any winds that tend to flex your open top. I also attached an 18" long piece of aircraft cable from the base to the door, so that wind will not extend the bracket beyond its maximum expanded length and not place undo torque on the device if a gust tries to force the top open. I also placed the small pin that holds the "t" bracket to the plunger with another small bolt and nut. Parts cost me about $5 at the local hardware store. The seller, Potting Blocks, has contacted me and has reimbursed me for the purchase price. He told me he will contact the manufacturer, J. Orbesen Teknik in Denmark about these defects and will see if he can also start sales with an optional, more durable, galvanized and stainless steel version of this opener, which are also in their product line.

Works great in my greenhouse. I automatically open and close with the change in temperature. Opens automatically when it's hot and closes when the temperature drops.

I bought 2 for my Harbor Freight 10x12 greenhouse and installed them on the back 2 vents so I only have to use a ladder to open the 2 front vents. I had to drill into the window frame to install them, but that was expected. It reminds me of a storm door closer, but it opens vs closes. I will likely purchase 2 more of these to install on the front half of the greenhouse in the future, as long as they hold up well throughout the year. I'm very short, and as such, do not like heights, so something that saves me from climbing up a tall ladder 2x a day is worth it. Pros -It opens and closes the window vents based on -temperature to let the heat escape. No more having to drag the ladder to the back of the greenhouse to open the rear vents, which means I dont have to constantly move my plants in the back to get the ladder in. -It opens almost triple what the OEM parts allow, which vent out a lot more heat and give more ventilation for a cross breeze. -It has 2 springs, one on each side to close the window, which help to stabilize the window against light wind. (I thought this opener would have to be removed before light storms, but the windows with this opener fare better than the windows without) -Neither install directions nor the ad summery say this, but if you squeeze the parallel bars of this opener closest to the part where it attaches to the window, the whole opener pops off the window attachment. The reason this is important, is that it makes it easier to install the gass piston, and you can remove the arm from service to lock the window down during bad winds. Cons -It took a while to arrive (weeks) as it shipped directly from China. Though, it was free shipping. -The install directions were terrible at best. All I can say is don't give up on trying to install it. Helpful hints Put the pistons in the refridgerator for a few hours as it makes installing it easier. Leave them in the fridge until its time to install them into the arms. If you take them out early they'll expand and you'll have to fight it. Also, take the springs off the arm to install the entire thing and put them back right after installing the piston. Another reviewer added an additional piece of aluminum to the window frame. I thought this was unnecessary, however if you have a harbor freight greenhouse the arm will torq the crud out of the frame.

I bought this a few years ago and love it. I broke a component, admitted as much to customer service, and asked to buy a replacement. Instead, they sent me a replacement component at no charge. The unit is well constructed - the damage was 100% my fault.

Works very well to vent our DIY greenhouse. I'm moderately handy but had never installed one of these before, and was able to figure it out. The opener definitely makes a difference in maintaining the max temp, and so far has worked flawlessly in both hot and cold weather (closes down tight when cold and doesn't open until it warms up the next day). If you're working with a manufactured greenhouse it likely has hinged vents already, but since our greenhouse is all DIY framing and plastic sheeting, I decided the size of the opening I wanted, then ahead of time framed out a wooden frame to go over the opening on the greenhouse structure, and serve as a "base" for the vent panel, and then built a lighter wooden frame covered with greenhouse plastic to act as the vent panel and cover the opening of the base frame, and mounted the vent panel to the base with hinges. So the vent panel opened and closed against the base frame. I put it all together down on the ground ahead of time, and added the vent opener in the cool of the morning so the lifter was in the "Closed" position. So frame, lifter and cover panel were all mounted nicely together and aligned well in the closed position. Then all I had to do was mount the base frame over the opening on the greenhouse, rather than trying to screw the opener in place, adjust it etc on top of a ladder.