Automatic greenhouse ventilation: advice wanted please

[supersprout]

My greenhouse has manual vents in the roof, and I would like to fit automatic ones. My friends' greenhouse has the sort that don't need electricity to run, but I can't figure out how they work.

Can anyone advise me on how to convert manual to automatic vents please?

How do they work?
Is there a good sort to get, i.e. are some makes/types better than others?
Is it difficult to fit them, i.e. should I get an expert to do it?

Thank you, hope someone can help  ::)

[supersprout]

[Svengali]

It is possible to buy - at around £26 - pneumatic window openers. They clip on to virtually all (aluminium) windows in about 10 mins, onlt tool needed is a screwdriver.
They work by the air in the cylinder expanding with heat, & extending the support rod.
Mine work a treat, and I can highly recommend them. I will look in my catalogues, & try to post a link.
JeremyB

[Svengali]

Try this!
/www.twowests.co.uk/TwoWestsSite/category/VENTIL_VENTOPEN/

JeremyB

[Svengali]

Or this!
JeremyB
http://www.queenswood.co.uk/index2.shtml

[MrsKP]

i've always wanted a pair of those lawn aireater shoes  ;D

[derbex]

I've got a couple of Bayliss XL? vents -wel worth it -around £20. Yup, 10 mins and a screwdriver.

Jeremy

[euronerd]

Here comes the killjoy ;D. When I bought my greenhouse some years ago, they advised fitting two of these - one high and one low. You could see the logic behind it, airflow and that. The low one btw is a self contained louvre vent the size of a normal pane, quite standard I believe. Anyway, for the first season, the low vent didn't work due to a faulty link, and it was only after I'd fixed it that you could feel a real difference. Only trouble is, it eats into the budget somewhat.

Geoff.

[supersprout]

Thank you all, will follow those links etc.

My chums in Norfolk have a beautiful but 'past it' old wood framed Dutch greenhouse, and have offered their roof vents when they demolish it (breaks all our hearts, there are huge floor to ceiling glass panes Ideal for Cold Frames). Not sure if I should accept, or buy new, so will follow your links/examples and should have lift-off either way by high summer! ;D ;D ;D

Groan mrskp, but I always wanted to be able to stand at an angle of 45 degrees without falling over lol. I send my son out in his rugger shoes and voila ;D ;D ;D

[tim]

Pneumatic? Most work on mineral expansion?

We have 8 - plus bottom vents - couldn't cope without.

[euronerd]

I always thought it was alcohol Tim, but didn't want to upset the applecart. :)

Geoff.

[laurieuk]

I have had auto-vents for over 20 years as already said I would not be without them, the only problem that can arise is that with a very strong wind the vents themselves are not secure and can flip open.One year one did fold itself right back, I now tie a length of string long enough to allow good opening but short enough to avoid damage.Remembering to take it off when the strong wind threat is past.

My greenhouse has manual vents in the roof, and I would like to fit automatic ones. My friends' greenhouse has the sort that don't need electricity to run, but I can't figure out how they work.

Can anyone advise me on how to convert manual to automatic vents please?

How do they work?
Is there a good sort to get, i.e. are some makes/types better than others?
Is it difficult to fit them, i.e. should I get an expert to do it?

Thank you, hope someone can help  ::)

[supersprout]

That's really useful advice laurie, thank you. Another use for string, yaaaay! ;D

[tim]

Alcohol? What a waste!!

Flipping? I can imagine that happening to the one we had on the lean-to. Fortunately, the ones on the other 'house are built like the Forth Bridge.

[euronerd]

Nice bit of engineering there Tim.

Geoff.

[chriszog]

Mine are filled with parafin wax that expands in the heat forcing the vent open.