Model |
Roof Vent |
Side Vent |
Heavy Vent |
Windy Site |
| Sesam |
Yes |
No |
No |
No |
| Univent |
Yes |
Yes |
No |
Yes |
| Bayliss T.S. |
Yes |
Yes |
No |
Yes |
| Hydraulicheck |
Yes |
Yes |
No |
Yes |
| Super |
Yes |
No |
Yes |
No |
Note: All vent openers can be installed in series to open a long or heavy vent. |
Vent Design
To avoid excessive temperatures in the greenhouse, it is necessary to have enough vents of adequate size. Ideally, roof vents should equal 20% of the floor area, plus lower fresh air intake vents equal to 10% of the floor area. Manual opening and closing of vents is easily done, but requires two trips to the greenhouse daily without exception. One sunny day with vents closed and plants look like last week’s salad or candidates for dried flower arranging. A cold night with vents left open will cause some plants to shiver to death and your heating system may croak from exhaustion. (Or you will croak when you get the heating bill!) So give the plants (and yourself), the care and peace of mind deserved - automate the vents!
Solar-Powered Vent Openers
How they work: The opener has a metal cylinder containing a mineral wax which expands with heat. This pushes a piston that opens the vent via a leveraged arm. As the temperature cools, the wax shrinks and a strong spring closes the vent and resets the piston. Opening and closing are gradual adjustments, allowing just the right amount of air flow for cooling. |
