Howdy, I too have an 8x12 green house. Wish it was larger, or better yet, a solarium built to the house. Inside are larger plants that no longer fit in the house. Citrus, Agaves, a few Aloes, Olive tree, variegated Ginger, and a few other odds and ends. Plants are kept in the gh during winter months..once temps warm up, plants are set outdoors. With utility prices, why pay extra when plants do well outside, not to mention easier to manage...? The first year it was erected, 'December, Christmas present,) on the coldest night of the year, the heater went out. In the process, I lost either 32 or 37 plants which froze. I cried, literally cried. After that dreadful night, we figured the problem and made sure the gas heater was working. We added an electric heater in case something went wrong with the gas again. We also purchased a temp/guage/alarm. The guage displays indoor, outdoor and gh temps and humidity. If temp drops to 45F, the alarm beeps. The guage is kept in the house. Mike, although Feb is cold, 'usually the coldest month of the year,' the sun is stronger and will burn certain plants. I hesitate adding shading since most plants are sun lovers, and eventually adapt to strong rays. During summer, gh temps reaches 117F+. This last summer, especially July, temps rose 140 and higher. Even with two opened vents and the storm/screen door ajar. Although my gh is on the small side, it's great having extra space. Don't know what I'd do without the extra room. It's a great investment, especially for those of us who have, more than a few, plants. lol. Toni

Thanks for the feedback, cuestaroble. I had wondered about the single wall, I think they have some sort of corrugated shaped foam to seal the end pieces, but I do think a twin-wall product would be better than trying to create some kind of "air pocket" after the fact with bubble wrap, plastic, etc. It sounds like the more vents the better, here in Zone 7. I'd originally wanted to custom-build a greenhouse out of mostly sliding patio doors so that I could really VENT it (even my tiny 6x8 HFGH was an oven on sunny days, and that was missing half its panels). When I saw this, I thought a similar pricepoint but without me doing all the work sounded great. But might be too good to be true. The fabricator is supposed to call me when he next brings a shipment to our area so I can go look at in person. We shall see and I will update then. Any other feedback or comments in the interim are welcome!

UNless you are planning to collect rare and extremely ultratropical plants, no plant you would grow would need a round the clock winter temp of 60-70F. 70 daytime and 48-55 nighttime would be fine for most. Brugmansia actually prefer cooler temps and would be fine in a GH that was kept at 40-45F at night, but other things you had might not be happy then. Unless you are going to grow stuff like heliconias, ultratropical gingers, Episcias, maybe Taccas and some of the more tropical orchids, cold sensitive palms (most of which palms can take to the high 30's-low 40's anyway) etc you would be wasting money to heat your greenhouse to 60F at night.

have you considered a Harbor Freight GH 6x8 go on sale for like $299 and you can get a 15% off coupon on ebay for $5 or less. I got my 10x12 HFGH on sale and used a 15% off coupon too for under $550... I'm sure you must have seen all the posts on this forum on these...and even though putting one together might be a challenge (no comments from the peanut gallery) you would at least be getting one in new condition..no telling what damage could occur when taking stuff apart...not to mention gas for driving several hundred miles? just a thought (I"m completely a novice here, but that's what my sentiment would be, I'm sure others will chime in too.