I did quite a bit of research on solar greenhouses some years ago. I don't believe you will be able grow year round without supplemental heat & insulating shades/ covers for the glazing.
There are many good books on greenhouse management. A trip to the library may be in order. At this point, I'd be happy with a south facing window; you will have a blast with your greenhouse.

I have a little 6 x 8. It's unheated though so not much chance of growing year round. It's just a place to start plants a little earlier in the spring and soak up some sun. I go out after most snowfalls and brush the snow off so the panels don't get damaged. It's amazing how warm it gets on sunny days, it's nice to smell dirt in January! This was the first winter for it and it's held up really well. Mine was from Harbor Freight sales (just over $200 with a good coupon), if you go on the greenhouse forum there's lots of information.

Hopefully this photo will work...

Here is a link that might be useful: Backyard and greenhouse

HI I have a HFGH in zone 4. 45 minutes away from you in Waushara county. I would advise you to go to the greenhouse forum. They have tonnnnnnsssss Of info and pictures for you for you to look at...... Barb

"Mine was from Harbor Freight sales (just over $200 with a good coupon"

Is that real glazing? Looks like a great place to start plants. $200 is pretty reasonable.
We did the window on top of hay bale walls last year & harvested spinach & greens in early March. Was a relatively mild winter tho.

I have two of the small HFGHs and, yes, it's real glazing. It's a double wall polycarbonate. It is a bit of a hassle to get togther, and needs some good insulation. AND all the usual extras that go with a greenhouse, but I've been very happy with mine. Here's some pics of mine...The link should work.

Dave
Milwaukee

Here is a link that might be useful: My Greenhouse