EricST11 -
Nice looking greenhouse, but what is the thickness of the polycarbonate panels. 4mm, 6mm, 10mm?
If it's 4mm I wouldn't buy it. Yes, it's nice and big but 4mm panels are about 1/8" thick. Not much snow load ability. We have a greenhouse that is 10mm twin wall polycarbonate panels. We put a bubble wrap type insulation on the inside during the winter and grow tomatoes year round. We're in the mountains of Colorado. We use a 25,000 BTU gas heater and the tomatoes in January and February are wonderful.
The other thing is that it is so high. That's a lot more cubic feet of air to heat in the winter. Just a couple of thoughts for your consideration. Here's a pic.