Greenhouse double film

  • Greenhouse double film

    Posted by Southensimplicityhomestead on December 14, 2022 at 8:26 pm

    Got a question for you all. We are looking to be getting cold next week down into the 20-30 degrees. We are looking into a adding the double poly film. Does anyone now how much warmer it stays inside? Our greenhouse house is also heated by wood stove buy I am afraid that it still might not be enough to keep up the temps. Any help would be greatly appreciated.

    Thank you

    RedDutchessFarm replied 11 months, 1 week ago 5 Members · 4 Replies
  • 4 Replies
  • welchfarm

    December 14, 2022 at 8:59 pm

    I have had better luck using small ceramic heaters on a thermostat.

    inside fans moving air help. Exhaust fans will come on if you produce to much heat when the sun comes up there goes the heat you just produced at night

  • AutumnRidge

    December 23, 2022 at 11:30 pm

    By doubling the layers of Greenhouse film and adding an inflation fan to expand the layers 3 – 5 inches apart will save you approx. 45 to 50% on heat loss. Use infrared film and you can save another 15 to 20% on heat loss especially on Clear cold nights. If you have questions feel free to ask. I use to be a Greenhouse construction and managment consultant.

    • AlphaDelta

      December 24, 2022 at 3:06 pm

      I’d love to hear more. I assume the fan is inside the structure, so warmed air is circulating? We tend to have warm Winters (South Texas), but like right now are below 20°f. By Wednesday we’ll be back in the 70s. I’m gone a lot, so need to automate as much as I can afford. Thanks for any input!

  • RedDutchessFarm

    December 25, 2022 at 4:38 am

    The formula for calculating btu’s needed to heat a greenhouse is:

    Total number of square feet of exterior of greenhouse(roof, sidewalls, endwalls)

    Multiplied by:

    the number of degrees you want to maintain between outside temperature and inside temperature

    Multiplied by: 1.14 for single layer plastic. -or- .73 for double layer inflated plastic


    2500 square feet of exterior area X 60 degrees (if it’s 0 outside you can keep it 60 inside) X 1.14 for single layer plastic equals:

    171,000 btu’s

    X .73 for double layer inflated equals:

    109,500 btu’s

    A huge difference between single layer and double layer inflated!

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