The question of how to optimize your green house growing is assisted tremendously by controlling the temperature and ventilation of the house.
We have been selling 'Bayliss' auto vents for over twenty years for many sensible reasons!
They require no power supply - air or water or hydraulic pumps - They work ingeniously by solar energy - as the house temperature rises a wax filled ram pushes open your vent or window and as the temperature drops, strong springs draw the vent or window closed.
So simple - as the sun comes out the vents start to open and as the sun goes behind a cloud the vents start to close!
Your plants will just love the consistent temperature conditions.
 

Mk 7 Standard Autovent Unit Product Code: MK7ST

Designed for aluminium or timber framed vents measuring up to 60cm square (2ft square) and lifting a load of up to 6kg (14lbs).
 

Mk 7 Triple Spring Autovent Unit Product Code: MK7TSU

Greenhouse autovent suitable for opening top hung aluminium or timber framed vents measuring up to 3ft x 2ft (900m x 600m).
 

Mk 7 Hydraulicheck Unit
Product Code: MK7HU

The addition of a small hydraulic damper which we have called 'hydraulicheck' to the Mk7 Autovent, offers the best answer yet provided to the problem of wind damage of lightweight vents.
 

XL Autovent
Product Code: XLA

Budget "clip-on" model lifting a load of up to 5.5kg (12lbs) giving a maximum opening of approximately 12". The unit measures 11" in length and is supplied in satin anodised finish only.
 

Mk 7 Super Autovent Product Code: MK7SU

Similar in design to the Mk 7 model but larger (151/2" overall length), the Mk 7 Super Autovent is suitable for operating heavy double glazed conservatory and greenhouse vents.
 

Mk 7 Super Victorian Unit Product Code: MK7SVU

The MK 7 Super Victorian model offers an unusual attractive and useful addition to the period style conservatory. Its design is based on patterns taken from a mid Victorian publication thus lending an air of authenticity to this modern and environmentally friendly product.