In just looking at the solar star, it does not show any roof/bottom vents, as far as I could tell. For any of your choices, adequate passive ventilation from roof/bottom vents is preferable. The reason is that even in NY, on clear sunny winter days, the GH inside temps will be well above the outside temps without adequate venting or shading. Unless you have large capacity fans/intake vents to account for at least one air exchange per minute, the passive vents are much less expensive, especially in the winter. Also, the cost of the GH structure itself is about 50% of the total cost to get it up and running, based on my experience. Site prep., leveling, gravel base, in-coming water pipes, irrigation system, mist system, electricity/gas provisions, timers, benches, pots, media, fertilizer, etc.take up the other 50%.

Hope this helps in your decisions.

Thank you for the sage advice.I would keep these things in mind when making my final decision.

I can only speak to the Riga, which I own and love. I would build another without a moment's hesitation. The thing we love most about it is that it's well-designed and robust. It has not budged, sagged, or broken in 6 years of active use. Also, the US importer and distributor has been very helpful with extra parts and whatever we've needed over the years.

Assembling the Riga is not "somewhat easy" unless you are already a contractor. I'd call it "somewhat difficult," but doable.

Sounds like you'll be heating your structure so the #1 attribute I'd be looking for is insulation and heat retention. Heating a porous structure in a NY winter will be a losing battle, so I'd think very carefully about how to do that most efficiently.

Good luck with your decision!

Karin,
I have been leaning towards the riga myself, mainly due to positive feedback from the members.I am planning to heat the greenhouse with propane and an electric heater as backup.I am trying to overwinter mainly jasmines,citrus,and some curry plants.I think I need to keep a minimum of 45F.Riga XL has 16mm triple walled polycarbonate which should be pretty good for insulation.The main issue might be the foundation and floor insulation.I am still deciding on different options (asking for advice as well please!)

Triple-wall polycarb is indeed the most insulating of the greenhouse coverings. Good choice for your location.

'The main issue might be the foundation and floor insulation'.

Insulating greenhouse floors is somewhat counter intuitive. The vertical area directly underneath the greenhouse walls should be insulated in cold climates, but under the floor, not needed or recommended. Warm air rises....

The attached pdf gives more details.

Here is a link that might be useful: greenhouse floor insulation

Yes, I'd echo what Cuesta said. Think of the foundation insulation as a curtain that extends downward into the soil, all around the perimeter of the greenhouse. We went down 16" and put in 4" of styrofoam (2, 2-inch boards) all around.

The floor itself not insulated. Ours has concrete pavers set in sand for the aisle and work area, and then garden soil where the planting beds are.

Another big key for heating that is often overlooked is to just heat the area where the plants are. Often there is no need to heat the whole structure. Instead, use frost blankets or a cold frame over the plants, and just heat inside that. Best yet, put that little cold frame in the warmest part of your structure. By doing that you will save tons of energy and money!

A Riga with triple wall 16 mm panel sounds ideal, nice!

All great suggestions.Thanks Cuesta and Karen for the ideas.Insulating 16" deep all around the perimeter should provide a great thermal break .I just have to figure out if I can do it myself.(rent a small backhoe?).I do want to spend the time doing the foundation etc correctly before actually purchasing a kit.

I did ours by myself but it's only 10 x 14, so not so huge. It was helpful to have the kit on hand prior to digging so I could fit the foundation frame around the styrofoam. I also did have help from my garden kitty, but in retrospect it's not clear just how helpful she really was. :)

Here's a pic of DH at the very beginning of construction - you can see the top of the styrofoam just inside the Riga foundation frame.

I vote Riga! I've had mine for several years now and I still love it. Make sure to budget in electricity and plumbing which will make life so much easier.