Univent Automatic Opener with Hardware to mount to shutter
- SKU:
- JAS1A/1AH
-
Description
The Univent Automatic Vent Opener by Ken Bar is a passive, no-electricity way to automate greenhouse ventilation, often sold as a solar vent opener because it runs on the sun's heat. A sealed wax cylinder expands with heat and pushes an aluminum shutter vent open as the greenhouse warms; when the air cools, the wax contracts and the vent closes. No wiring, no power draw, and nothing to switch on.
The kit includes the hardware to mount directly to a shutter vent. It lifts up to 33 lbs, enough to drive a heavy aluminum shutter. Set the activation temperature between 60°F and 70°F by turning the cylinder, with the vent reaching fully open by 86°F. For shutters 30 inches and under, one opener is enough; for larger shutters, use two for even operation.
Because it runs on ambient heat rather than electricity, the Univent is a reliable choice for off-grid high tunnels and greenhouses that need passive, hands-off temperature control.
The Univent Automatic Vent Opener is a passive, no-electricity way to hold temperature in a greenhouse or NRCS-funded high tunnel. A sealed wax cylinder expands as the air warms and pushes the vent open to release trapped heat; when the air cools, the wax contracts and the vent closes. It's often sold as a solar vent opener, since it runs entirely on the sun's heat rather than electricity: no wiring, no power, and nothing to switch on.
This Ken Bar model ships with the hardware to mount directly to an aluminum shutter vent, and it lifts up to 33 lbs, enough to drive a standard shutter. For a fully passive setup, pair it with our Aluminum Shutter Vents so the vents open automatically while you're away.
Technical Specifications
| Power Source | Passive thermal wax cylinder (no electricity required) |
| Activation Temperature | Adjustable between 60°F – 70°F |
| Fully Open Temperature | 86°F |
| Lifting Capacity | Up to 33 lbs |
| Sizing Recommendation | Shutters 30" and under: one opener. Larger shutters: two. |
Key Benefits
- No electricity: The wax cylinder runs on ambient heat, so there are no wiring runs, no power draw, and nothing to fail in a power outage.
- Automatic protection: Vents open on their own as the greenhouse heats up, so crops stay protected on days you can't get out to open the vents by hand.
- Adjustable start point: Set the opening temperature anywhere between 60°F and 70°F to match the crop, with the vent fully open by 86°F.
- 33 lb lift: Enough force to operate a heavy aluminum shutter vent, not just a light hobby-house window.
Frequently Asked Questions
Q: How does a Univent automatic opener work?
A: The opener contains a sealed cylinder filled with a wax that expands as it warms. As the greenhouse temperature rises, the wax pushes a piston outward, which levers the shutter open. As the air cools, the wax contracts and the vent closes. The whole cycle runs on heat alone, with no electricity.
Q: How do you adjust the temperature on a greenhouse vent opener?
A: The activation point is adjustable between 60°F and 70°F. Turn the threaded cylinder to set the temperature at which the shutter starts to open; from there it moves to fully open by 86°F. Set it lower for cool-season crops and higher for heat-tolerant ones.
Q: Can I leave my automatic vent opener out in the winter?
A: We recommend removing the wax cylinder for the winter. Storing it indoors protects the wax and seals and extends the life of the opener. In spring, reinstall the cylinder and reset the activation temperature for the season.
Q: How many openers do I need for my vent?
A: For shutters 30 inches and under, one Univent opener is enough. For larger shutters, install two so the lifting force is shared, the frame doesn't twist, and the extra weight is handled evenly.
You May Also Need
Polaris theme designed by epicShops