Roof Vents

Hiya John.

I guess it depends on whether or not you're looking for circulation as well? My 'gut' feel is that they should be as far apart as possible to get a bit of flow going. It'll be interesting to see what others think

 

I`d try to put as much distance between the roof vent and the intake (door) as possible. If they`re too close the air will just come in and be drawn straight out by the roof vent. If the roof vent is at the opposite end, the air has to travel the length of the gh before it can escape.

 

Sounds good. I have 2 (offset) vents in the middle directly above where I site my heater, so when it's on the automatic openers open the vents above, letting all the heat out and making the heater turn up even further until the windows are wide open and the heater is on full blast. That might be a slight exaggeration, but I'm sure that a roof vent at each end would be better. Maybe greenhouse manufacturers suppliers think 2 in the middle looks best?


P.S. Obviously I exercise some form of manual control over my autovents to stop them behaving in such a stupid fashion, but if we're away and a neighbour is in control charge it costs a lot more in gas.

 

I have vents on alternate "strips", on both sides and they are staggered [with respect to the opposite side]. I agree with others that max distance between them is best. With door closed then you will get convection from floor-level vent and chimney-effect up-and-out-of the vents. If they are some way apart then quite a lot of air will be moved, so there will be fewer hotter spots.

With door open you will get some draught as well as convection.

With staggered vents you may get air coming in via the one facing the breeze, that will then blow through and out of the other, and I think if you offer it a straight path, by having them opposite each other, that the breeze will then pass through without moving much air with it.

But I'm just talking out loud ...

Personally I'd want to see two roof vents each side and one, or maybe two, louvres low down.

 

How annoying for you :(

 

Can you fail to fit new vents every weekend this summer pls? In fact you could become a tailor

 

My automatic vents start to close around 60 f is this the norm.many thanks.

 

I would think you want them fully closed at 60F - keep that nice warmth in for maximum growing. I'd want them fully open by around 80F at a guess. It would be handy to know what the temperature difference is between just-opening and fully-open - to see how many degrees it takes to get the wax fully expanded.

 

It's 70 in mine at the moment and they are partially open?