Automatic Vent Opener - Standard

Use on Coldframes or Greenhouses

Item Number: SEF110


In Stock! Ships from Northern CA.


In Stock! Ships from Northern CA.

Buy Big, Save Big! As low as $31.49 each!
  • Buy 10 for $31.49 each and save 11%


Ingenious temperature-sensitive device that automatically opens and closes coldframe lids, greenhouse windows and even skylights. Works throughout the day and maintain a constant interior climate, something impossible to achieve by manual adjustments.

  • Requires no batteries or electricity.
  • It can be adjusted to start opening between 60-77°F. Fully open at 86-90°F. Fully closed at 55°F.
  • Strongly recommended for all our glazed season extenders because it dramatically improves plant growth.
  • The hydraulic cylinder comes with a 1 year warranty. The average lifetime of the cylinder is 5-10 years, although some can last up to 20 years.

Replacement cylinders are available.

Screw directly into polycarbonate panels, wood, or metal frames. The Standard Vent Opener can open a hinged window or vent weighing as much as 32 lb. For larger panes use the stronger Gigavent with all metal construction, to lift up to 65 lbs.

Note from the manufacturer: Recommended to lubricate the piston rod yearly, this will help extend the lifetime of the hydraulic cylinder. Don't use solid grease, as dust particles "glues" easily onto the piston rod and can damage the rubber. Also do not forget to unlock the vent in the winter if leaving the vent openers installed. Even a even a weak winter sun can heat the hydraulic cylinder sufficiently to make it start pushing the piston rod outwards.


  • Replacement Parts Available

Useful Information

Use Instructions

Videos & Articles


What You May Need

Shipping Information

Shipping Weight: 2.00 lbs. Dimensions: 15"L x 3.75"W x 2"H


Enjoy these

I have an economic green house that had manual vents in the roof. I installed these and now I don't have to remember to open and close them anymore!

Reviewed by on

One year

This worked fine for the first season. The second season it did not work at all.

Reviewed by on

Agree with everything said but one caution

We have 2 in our 8X16 and I agree with earlyer comments. Just one caution We live in an area that is windy at times. I would install a small link chain that would limit the max opening of vent to just where it stops opening itself. Our's would pull out of the cylinder as the wind grabbed the vent. It would then flap in the breeze which could damage the vent.

Reviewed by on

Excellent Tool!

Easy to install (after analyzing the instructions carefully), functions smoothly and efficiently. Has already proven to be invaluable in growing early season plants.

Reviewed by on


Bought one of these 8 years ago and it's still growing strong. Absolutely essential cold frame accessory for high altitude gardens where sun is intense but nights are cold.

Reviewed by on

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