I also chimed in on your other thread, but since this one pertains even more closely to what I actually have, I'll give my two cents again...

I have a 9x13 sunroom on the front (south) of my house here near Santa Fe, NM (z6 also). It has small windows on the east and west, and is almost all glass to the south. The rest of the wall space is typical insulated 2x6 frame. This room never gets really cold, but it may dip to around 50 degrees when we close it off from the rest of the house (which is every night during winter). We never heat it directly.

It is simply a wonderful place to be on a sunny winter day (it helps with the passive solar heating of the house which is our primary heat with wood stove backup), and functions well as extra living space from about September through April. Too hot in summer, and not enough direct sunlight for good growing (of veggies at least).

In terms of growing space there is nothing better. As soon as the low sun angle starts kicking in, plants really begin to thrive.

Of course this is all in a very sunny climate, so can't be applied precisely in PA, but then again, your nights tend to stay warmer (our January average high is 43 and low is 17).

nmfruit thanks for your experiences. We have gone down to the teens in winter frequently the last 2 winters, with -11F happening 1-2 times last year, but that's rare. My sunroom will be facing east, so no terrible full sun in summer. I am hoping to keep some semi tropical houseplants in mine. Maybe some zone 8 plants in pots. I will have much less sun in winter as you suggested. It will be likely in spring next year when we get it. It's good to know that yours stays fairly warm in winter at night, if you are getting 50F in winter I may get 30F, fine for some zone 8 plants. Thanks nmfriut

Well, NMFruit, It looks like we may not be getting that sunroom too quickly. They want $21,000 after a few rebates that we may or may not qualify for, and the offer expires on Dec 15, 2015. We were planning to start the project in spring/summer 2016. So the whole thing is in limbo for now. I know that eventually we will have some sort of sunroom, solarium or large windowed building built, eventually. I am happy to have a large south facing window in our basement. I have my Bird of Paradise there now. It was outdoors in the summer, I would love to not have to reduce it's height in the next couple years. I am interested in a mandarin orange tree, etc. So does anyone have any info on perhaps making your own porch enclosure, you know, large windows and a nicely windowed door for at or under $12,000? That is our budget. We have been able to find another Pittsburgh area company, "Patio enclosures". I told them our budget of $12,000, and the size we want (7' X 9') rounded off. So they will likely want to build a tiny closet (poor persons closet) size sunroom/solarium. We just may just have a builder build the whole thing, versus a sunroom company putting their rooms up. I always heard that these sunroom company's buildings were cheaper than a contractor sized room, that is obviously not true. WE didn't include any real "comforts" on our estimate from 4 seasons sunrooms either. No heating/Ac units. Just the bare bones, with the best glass though. Well, just wish us luck at finding what we want with a good price, and of course, if anyone has any ideas how to do it all at a decent price(within our budget), But bear in mind, nobody in my family can build anything, unfortunately.

It's me again Poaky1, from the above post. Our budget is now $8,000. So I will be waiting a while for my sunroom. But, we will get one eventually. Forget the above post, until I can get one built, etc. Then I may have questions about certain plants in winter in the sunroom. Thanks anyways.