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Wi

I'm looking to build a greenhouse. I want to be able to use it throughout the winter, here in WI. I'd like to get a kit, but most of the kits seem to come with 8mm twin-wall polycarbonate. I'm wondering if anyone has one that they heat all winter, and if so, how thick is the poly and do you think it is enough. I don't want it cost a fortune to heat, but from what I'm reading the R-value isn't much different from 8mm to 16mm, and the price is extremely different. Hope this makes sense and isn't too rambling, any advice is appreciated.

1/12/2012 4:51:42 PM

Hinckley MN

Double layer, inflated polyethelene film is just as efficient for heat retention, mostly because you have fewer seams to leak air. It is also lots cheaper but lasts half as long (4-6 years). If you must have polycarbonate, I'd go with the cheaper twinwall panels and upgrade in 10-12 years when it yellows.

1/12/2012 7:02:42 PM

Menomonie, WI (mail@gr8pumpkin.net)

Craiglist minneapolis had a bunch

1/12/2012 11:02:32 PM

Menomonie, WI (mail@gr8pumpkin.net)

http://eauclaire.craigslist.org/grd/2794314894.html

1/16/2012 1:31:05 PM

Alaska

Double layer poly has better R value and won't yellow. I finally after 14 years replaced the poly on one of my commercial greenhouses. I know they say it's only good for about 4 years but I'd beg to differ. The only real problem I had with the plastic was of my own doing. You need to use an air diffuser where you blow air between the two layers. Blowing air directly into the poly weakens it over time and it becomes brittle and blows apart in about 5 years. I have the 8mm on my Nexus 30x100 and almost to the day 10 years after install it started to yellow. The replacement cost are gonna be huge. The cost for replacing the double poly on my 25x88 was 750 bucks. I did the work of course. So for me better R value and cost poly wins hands down.

1/16/2012 3:32:47 PM