solar heating cloudy days?

hairmetal4ever(Z7 MD)March 27, 2014

Generally speaking, do you find that your GH is still warmer than ambient outdoor temps on CLOUDY days, without an additional heat source?

If so, how much warmer?

I don't have a GH yet. I ask because whenever we have a March snowstorm, the weatherfolks talk about how the sun is so strong in March that, even through the clouds, we may see most of it melt.

Does that mean that, at least during the part of the year where solar angle is higher, that a GH will get at least a little solar heating on cloudy days?

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With clear film, I get 15-20 degrees of gain on cloudy days, and 50 or more on sunny days. My greenhouse has the clear film, but my high tunnel of tomatoes has opaque film. It does not get quite as hot, and the tomatoes don't get sun scald as badly.

    Bookmark   March 27, 2014 at 3:30PM
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fruitnut Z7 4500ft SW TX

Even on the cloudiest days there is some gain. About like Robbie states. Mine even gains about 6F on heavily overcast nights. This is with IR and woven poly.

    Bookmark   March 27, 2014 at 7:28PM
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hairmetal4ever(Z7 MD)

I assume the gain is better in April than December?

    Bookmark   March 27, 2014 at 7:48PM
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My brand new greehouse has at least a 10-15 degree gain during the day on a very overcast day in oregon. But on a sunny day its much more like 20-40 degrees. during the night it stays at least 6 degrees warmer than the outside temp. which is good to keep tomatoes from getting cold stressed from 40 or bellow nights. i have a review of the green house i have on my youtube channel if you would like to take a look.

Here is a link that might be useful: TheItalian Garden

    Bookmark   March 27, 2014 at 9:40PM
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