Greenhouse Condensation and Glass Doors In Winter

waretrop

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waretrop
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#1
We have a large glass greenhouse, see avatar, with sliding glass doors at the entrance. In the winter if we don't get the air flow correct, condensation collects on the door and freezes in the runner. None of us should have much moisture on our walls and doors. That is a clue that our fans or air flow is not placed correctly.

When my greenhouse doors freeze I have a special hair dryer that I use to thaw it out. I keep it on hand at all times.
 

MoonShadows

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#2
I'm almost ashamed to admit this, but when I first got my greenhouse, I had no idea I needed circulation within the greenhouse. I have passive roof vents. I really don't like them. I finally places a big fan up near one of them to help vent the heat more efficiently. I'm probably going to install a regular greenhouse fan this Spring in the back wall.
 
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Anthony
#5
Hello guys, I'm looking at a greenhouse made by Conleys. It's a 12'Wx18'L steel frame gable style with polycarbonate glazing. It has one door and no roof vents. I would have to rely only on an exhaust fan ventilation system which consists of a fan setup to blow hot stale air out of the greenhouse and bring fresh cooler air inside the greenhouse via intake shutters mounted on the opposite end of the structure. Adding roof vents to this structure would cost an extra $3000, which I'd like to avoid to spend.
Do think that relying only on an exhaust fan ventilation system?
This is the link to the greenhouse

https://www.conleys.com/pages/hobby-house
 

MoonShadows

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#6
Remember the Conley Hobby House is a scaled down version of a basic commercial greenhouse, and I don't know of any commercial greenhouses that use roof vents, at least I've never seen any, and they do just fine.

Also, take a look at the shutter fans at QC Supply (https://www.qcsupply.com/commercial-industrial/fans-ventilation-controls.html). They sell Durafans. They are less expensive and appear to have good reviews from what I have read. I am thinking of buying one of these for my greenhouse.
 
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Arenas Valley, New Mexico
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Karen
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#11
I do have a condensation problem on occasion. I have a fan that circulates the greenhouse air through the raised beds. Supposedly it keeps the soil warmer or cooler as needed. We also have a solar fan that only runs when it's sunny. My 3 vents are able to open and close year round. We're on a very windy hill, so the vents provide great circulation while they're open. I'm thinking I also need to put in an electric fan to help with circulation and moisture condensing on and in the polycarbonate walls. Here is a pic:
 

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waretrop

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North Eastern PA.
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waretrop
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#12
I think Karen we up north have condensation is because of the difference in temp. You may not realize that where you are. Plus the air is dryer. I keep my greenhouse at aboutfrom 62 degrees in winter. When it is like 20 or even 10 and it has just automatically watered in the greenhouse you get condensation like crazy. Fans really do help allot.
 
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Arenas Valley, New Mexico
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Karen
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#13
I'm trying to keep my GH at 60F but it does go down to the low 50's if it gets very cold for us. I don't normally notice much condensation. It only happens when the difference in air temps is greater, and like you said, if it waters during that time. I do need to put in an extra fan.