Hi Dan. First, I must remark that you have an ideal situation with a south-facing area of those dimensions. Very fortunate! You could run a decent-sized business from there.
1) Using regular insulated glass doors will give you excellent performance.
2) I would plan for supplemental lighting. Commercial 8' shop lights would be ideal. But you might get more light than you think in the winter...
3) Not sure about this one...
4) I imagine that your climate would warrant the extra cost, within reason.
5) - If you want it to look nice (and plan to build it yourself), take the time to figure the details down to the 1/16th of an inch on paper before you begin construction. Having a carpenter friend help would be ideal.
- You can save a great deal of money by purchasing used glass door panels and adjusting your plan around the materials you end up with. I paid $40 for a pair of 4' x 6'8" panels (you don't really need the frame), and over time collected several more for free (two of which had the frames
).
- Ventilation is essential. Buy an automatic vent so your plants don't fry while you are at work on an unseasonably warm day. Also, plan on having a fan or two for multiple benefits.
- Plan on using thermostatically controlled heaters through the winter. Depending what you are using the greenhouse for, keeping it at a minimum of around 50* F works fine.
Dan, there are some really good books on greenhouses. See what your library has to offer.
You're right about TVille.
Any more questions? I would love to follow the progression of this project.