Announcement

Collapse
No announcement yet.

GH vs Poly?

Collapse

X
Collapse
 
  • Page of 1
  • Filter
  • Time
  • Show
Clear All
new posts
Previous template Next
  • #1

    GH vs Poly?

    I have a polycarbonate green house and a small polytunnel, In the GH I had a max min thermometer and recently bought one for the tunnel. What has surprised me is that the one in the tunnel shows a whole degree warmer on the minimun temperature. I suspected a variation in the thermometers but last night I swapped them over and the polytunnel was still a degree higher. I know its only a degree but when the weather is hovering on the frost level that could make all the difference.

    Is it generaly known that a polytunnel is warmer? or is it something to do with my particular situation, although they are side by side.
    photo album of my garden in my profile http://www.growfruitandveg.co.uk/gra...my+garden.html
    Tags: None
  • #2
    Is the greenhouse more draughty? Gaps between panes, ill fitting vents, and so on?

    I imagine that the only "join" on the Poly tunnel is the door frame, so absolutely no where for draughts to enter.
    K's Garden blog the story of the creation of our garden

    Comment

    • #3
      I wonder if glass dissipates heat faster than polythene,does the greenhouse heat up faster than the poly-tunnel Bill ?
      He who smiles in the face of adversity,has already decided who to blame

      Artificial intelligence is no match for natural stupidity

      Comment

      • #4
        R-values of some cladding materials for greenhouses. "2" would transmit twice as much heat as "1" would do.

        4 mil polyethylene = 1.20
        6 mil polyethylene = 1.15
        3 mm (1/8") glass (single layer) = 1.13
        Double layer insulated glass = .45
        4 mm (5/32") twinwall polycarbonate = .70
        6 mm (1/4") twinwall polycarbonate = .62
        8 mm (5/16") twinwall polycarbonate = .58
        10mm (3/8") twinwall polycarbonate = .53

        So on the face of it I think that 3 mm glass looks to be marginally better than 6 mil polyethylene (assuming that is what the Polytunnel is covered with ...) and a little bit better than 4 mil. Either way: much of a muchness by the looks of it.

        Twinwall polycarbonate would be a lot better but panels made from that have a habit of blowing out
        K's Garden blog the story of the creation of our garden

        Comment

        • #5
          Originally posted by bearded bloke View Post
          I wonder if glass dissipates heat faster than polythene,does the greenhouse heat up faster than the poly-tunnel Bill ?
          I currently have no data on that one BB.
          photo album of my garden in my profile http://www.growfruitandveg.co.uk/gra...my+garden.html

          Comment

          • #6
            It just seems to me that glass is hotter "to the touch" than plastic,so maybe it transfers heat faster,but how it could be practically tested is beyond me Bill
            He who smiles in the face of adversity,has already decided who to blame

            Artificial intelligence is no match for natural stupidity

            Comment

            • #7
              I'm confused with all this talk about glass when Bill said it was a polycarb GH................
              sigpic“Gorillas are very intelligent, but they don't have to be as delicate as chimps -- they can just smash open the termite nest,”
              --------------------------------------------------------------------
              Official Member Of The Nutters Club - Rwanda Branch.
              -------------------------------------------------------------------
              Sent from my ZX Spectrum with no predictive text..........
              -----------------------------------------------------------
              KOYS - King Of Yellow Stickers..............

              Comment

              • #8
                Originally posted by Bigmallly View Post
                I'm confused with all this talk about glass when Bill said it was a polycarb GH................
                Yes it is poly carb, but if glass is better its good to know.
                photo album of my garden in my profile http://www.growfruitandveg.co.uk/gra...my+garden.html

                Comment

                Previous template Next

                Latest Topics

                Collapse
                View All

                Recent Blog Posts

                Collapse
                View All
                Working...
                X