Clear Polycarbonate walls vs. twin wall polycarbonate

Hi All - I need help figuring out what greenhouse to buy. I found what I think is an awsome buy on ebay, http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=7757229880&rd=1&rd=1
I am seriously considering that one - I love the clear panels and it has free shipping. I like the Harbor Freight one too, http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=93358 it has the twin wall, but is quite a bit cheaper and I can get the 10' X 12' for less than the 6'x8' ebay one. Then there's the one on Home Depot, http://www.homedepot.com/prel80/HDUS/EN_US/diy_main/pg_diy.jsp?CNTTYPE=PROD_META&N=2984%205806&CNTKEY=misc/searchResults.jsp&cm_mmc=hd_goog-_-New-Search-_-D-28X-_-bid2
which also is intriguing, but it costs alot more.
My biggest question right now is this: What's the difference between the clear polycarbonate panels and the twin wall? I'm curious about stability, does the clear intensify the sunlight so it burns the plants, does it feel better to be inside the clear one vs. the twin wall?
Does anybody have any of these greenhouses? I live in southeastern Wisconsin, and will be using the greenhouse only in the spring and summer. Any help is appreciated - I don't want to make a mistake with this much money! Thank you so much!

I have seen in person the one you show the link for cgi. ebay.com. I saw it in Salem, OR when I was looking at the Sunshine Gardenhouse one.
That cgi.ebay.com greenhouse is a very cheaply thin polycarb. greenhouse. I really didn't like it all at. It just looked and felt like it would blow away so easily. But this is just my opinion. It is very flimsy, I think.

As for the single/clear poly. compared to the twin-wall poly, the single is just that. One piece of poly./plastic and the twin is a double layer of poly. which I really like better. You can still see thru it tho not as clear but almost. I think the twin poly. would protect your plants in the summer time.

Just my 2 cents worth. Carol

Thank you so much, Carol! The last thing I want to do is buy something I can't return, that I hate using because it's cheap. My husband would kill me because he's going to have to put it together, and he's buying it for me for Christmas. I have a little Charley's Greenhouse (i.e. expensive) cold frame made of the twinwall, and the twinwall panels are wiggly and don't stay put. I just don't want to get the same thing in a bigger version. Do you have a greenhouse, and if so, which one? Thanks!!

I really like my 6x8 Harbor Freight one. They didn't have the 10x12 when I bought it. We don't get snow here, so I'm not sure how it hold up to that, but wind and rain are no problem. I've only had a little problem with the roof panels slipping at first, but they are ok now. Here's a recent pic. It's heated by a 1500 watt space heater and I've lined it with bubble wrap. It stayed at 55 even when the temps were under 20. My husband built the foundation and put it together.

Twinwall has a couple of advantages. First, twinwall bumps up your R value from around 0.8 to around 1.4, a significant energy savings anywhere, but particularly in z5. Second, you got it, the light diffusion is important to prevent sunburn. Glazing can diffuse the light without impairing the transmission. And diffused light has been shown to improve a plant's photosynthetic efficiency.

Before you buy a HFGH, you should know that those who are happiest with their HFGH have made a series of well-documented modifications to the GH to make it wind and snow resistant and more usable on the inside. Off the top of my head, these modifications include adding EMT cross bracing to prevent bowing out of the center of the walls, addition of "captive" bolts in the assembly process, elevation of the foundation for more headroom, and additional screws to hold the panels in. I can refer you to threads with these details if needed.

SB

Loads of information! I also emailed a bunch of buyers of the twinwall GH sold on eBay, which turns out to be the Harbor Freight one. Most people love it but complained about the assembly instructions...Now I'm wondering if aluminum or resin is better framing because one of the contenders has resin framing. Anybody know about that? Stressbaby - you must be the garden guru here. You know ALOT - thanks for clearing me up (ha) on the difference between the polycarbonates.

chickensrus,
I am in the process of getting a greenhouse. I have been doing lots of research trying to figure out which one I want. I haven't ordered it yet but plan to real soon.
I was going to get a small one like you are looking at. But then my Mother gave me some money from the sale of my parents house (since Dad died a few months ago), so I am going to use that money for a greenhouse. Dad loved to grow things so.............to remember him by.

So I am looking at the Sunshine Gardenhouse. It is redwood frame with twin wall poly. I have seen 2 of those in real life and I really like them. I wanted something easy to put together since I may have to do it by myself. The Sunshine Gardenhouse comes with pre-assembled panels.
I hear the other types like the metal greenhouse are more difficult to put together but...............

I did see some Solexx greenhouse at the same time I saw the greenhouse you talked about and I said wasn't good. I wouldn't mind a Solexx one but they don't come in a 6' wide greenhouse yet.

So have fun trying to decide which one to buy. Is kind of fun looking and deciding.
Carol

For what it's worth, I purchased a home-attached greenhouse from FarmTek. I don't think they're the cheapest around, but the panels are pre-assembled and I built it by myself, although I don't recommend anyone doing that unless they're really ambitious (or crazy). They are made with 8mm twin wall and if you take the time to seal it up, it works well.
http://www.farmtek.com/farm/supplies/prod1;ft1_greenhouses_accessories_2-ft1_hobby_greenhouses;pg104917.html
I bought the biggest in that series, so mine's a 10' x 16'. I really like it a lot. The only problem is that's it's way too small now. I'm sure nobody else here has that problem. Here's the best picture I have right now, but it wasn't originally to show the greenhouse. You get the idea.
Stosh

Y'all are a wealth of info. Carol - do you have a link for the Sunshine GH? Intriguing...and Stosh - funny yours is like twice as big as mine will be and too small already - gives me the shakes...

That looks real nice attached to your house tho, Stosh. You always wished you got a bigger one. I know that is why I am going for a larger one than planned.
Here is a link for the Sunshine Gardenhouse
http://www.gardenhouse.com/
Carol