I purchased a 16x24 Atlas Snow Arch GH. They have many types, and it has held up well in all winds over the last 6-7 yrs. Some questions that will help you with your decission. What do you want to grow, how hot do you need to keep it in winter, What will you use to heat, and how much can you afford to pay to heat. Will you run water underground to the GH, electricity ? Does your township or burough ( local gov) allow gh in you neighborhood - Some require building permits. Good Luck, I enjoy mine and it does not matter how much it cost it is a grat place to be in the winter. MIKE

I have a post above but want to add another. I now have 3 10X12 HFGH's built as one. So now I have lots of room with GH's and can not add anymore. Love every one of them. I have 90 to 100 orchids hanging from the top. To do that I had to put chains in the middle of each GH so it could not bow out. That's alot of weight in all the clay pots. If I had more room I would probly have more GH's.

Jaderloon in SC does commercial greenhouses but they also sell an institutional package that several high schools in my area have built. I got the same one for my home greenhouse (24'x48') and have been very happy with both the greenhouse and the company support.

Gardenqueen87, Part of your question was -" Both greenhouses seem to employ a different way of moving the air. Is one way better than the other?" For most greenhouse crops, one complete air exchange per minute is needed. (volume of air within the greenhouse), and either passive-vents or fans can meet this need. One is not necessarily better than the other, other than the fact that passive ventilation systems do not require electricity. With fans, an output of 10 cubic ft / minute/ sq. ft of floor area is needed. For example, a 12 ft. X 18 ft. greenhouse (216 sq. ft. floor area) would need fans that could provide 2160 cubic ft/minute to achieve the needed one air exchange per minute.Check the specifications of the fans provided by the manufacturer. With a passive system, roof vents generally should be 20% of the floor area, and bottom-side vents 10%. Bottom-side vents are necessary to ensure the one complete air exchange per minute. For the same 12 ft X 18 ft. greenhouse with a passive system, top vents should be 44 sq. ft. and bottom-side vents 22 sq. ft. Check the specifications of the top vents, and ensure that bottom-side vents are included or can be modified into the design.