Our sunroom is on the southwest corner of our home. Maximum exposure. Mind you, there are very tall trees in the rear of our property that offer strategic bits of shade during even the most sun-drenched days, but the room is very bright nonetheless. Pale blue ceiling, bone white walls, windows everywhere. It's a wonderful space.

Mine is in the SE corner. Big overhangs on the south side, shade trees on the east help keep it from getting too hot.
Heat builds during the day, so SE seems better than SW, which would get direct sun at hottest time of day.
In NJ, in winter a north facing sunroom would be a big heat loser (on the S side, it could help heat on bright days, as long as those overhangs are at the correct angle).

I'll tell you my experience with my sunroom, and then I'll give you some siting and construction tips.

In many ways, sunrooms are a PIA room built on a fantasy experience. Unless you live somewhere like CA with a year round mild climate, having it be more of a "screen room/gazebo" type means they are unusable for about 7 months out of the year. They are hot in the summer and cold in the winter.

Heating and cooling is problematic because of the number of windows which don't have near the R value that a wall would. Buying triple glazed windows greatly increases the cost, but otherwise, you have an unusable room for much of the year. I've lived with one for 16 years, and the only time it's pleasant to be in is October/November and February/March. The rest of the time, it's uninhabitable.

We tried closing it in with windows and using a windows AC in summer, but that actually made it hotter and the AC couldn't really cope with the heat and humidity well without sending the utiiity bill skyrocketing. It's too sunny for houseplants to be really happy and not sunny enough for true outdoor plants to be happy.

Our next renovation is to rebuild it from scratch as a family room with deeper overhangs, actual modern insulation, and less and better quality windows. Hopefully, that will ley us reclaim the space. If not, well, as I said, it's a fantasy room for most buyers. They think how lovely it is with the wicker furniture and sunny view and don't learn the truth until they have to live with it.

A southwest location with strategically planted deciduous trees will let you have light but the leaves will block the hottest afternoon sun. It will still need AC in order to be cmfortable though. When the leaves fall in winter, the lower angle of the sun will allow it to shine right through the bare branches of the trees and give you some solar gain to help boost the heat for the interior. It will still need supplemental heat in order to be a 12 month usable room. My advice is to use the best quality triple glazed windows that you can, use foam insulation exclusively, and have it be on it's own zone by itself for HVAC. If it's large enough, you may even want it to have it's own individual system. All of those things add up to quite a bit of money, but honestly it's only worth doing if it's done right.

Reading this over, I sound a bit cranky. I'M sorry, but it's a sore subject for me right now. With the 106 degree heat yesterday, the sunroom was 140. That only moderately insulated oven is attached to my house which is having a hard enough time coping with the 106. Using an IR thermometer, the interior of the wall between the sunroom and house is 90 degrees. Inside the house it's 82, and I'm undergoing hot flashes plus sweating episodes from some medication I'm on. I really would have rather had a pool than a sunroom! (My husband tells me that a pool comes with it's own set of fantasy busters.)

Beautiful space! If you're trying to grow plants or heat your home, then south side is best...but, if you just want a light and airy place to sit or dine, I'd pick the northeast side of the home. It's not so hot in the summer and you could easily add screens and enjoy a cool breeze, in hot weather.

In the winter, it might feel a little cool, so if you could include a gas or wood fireplace...it would be beautiful and cozy! :)

The pic you posted is going to be impossible to construct economically and with good energy efficency. It's more of a greenhouse built in a classical architectural style.

It's all about calculating the sun angle at different times of the year. Your latitude +/- 23.45 will tell you the range of the declination angle (from directly overhead) at solar noon. If you live at 35 deg latitude, the sun will shine down at a 11.55 deg angle on June 21, and 58.45 on December 21. During the equinoxes, the angle is the same as your latitude. There are calculus formulas to determine the sun angle at any time of the day, for any day of the year. I can send you some info if you're interested. I saved my college textbooks from that particular class, for this very reason.

There are really cool ways to design exposures that let the sun shine into the space during the fall/winter and shade the direct rays in the spring/summer. The solar energy gail/loss can work out to be an advantage for most of the year.

One simple design is a southern exposure with a glass wall and an overhang.

A room with no exterior walls can become a sunroom with roof dormer windows and skylights. The same angles and calculations apply. If you wanted to capture sun at certain times of the day, as well as build a seasonal solar design, dormers are a way to achieve this.

jenswrens I had originally wanted a room like yours pictured and my builder said the same thing as aidan_m. It would be unusable for most of the year because it would be too hot in the summer and too cold in the winter. We ended up doing two "sunroom-like" rooms to allow them to be used year round and let in maximum sun while still being possible to heat and cool. The rooms are still not fully completed but I'd be happy to post pictures if you are interested in seeing our solution.

jenswrens I had originally wanted a room like yours pictured and my builder said the same thing as aidan_m. It would be unusable for most of the year because it would be too hot in the summer and too cold in the winter. We ended up doing two "sunroom-like" rooms to allow them to be used year round and let in maximum sun while still being possible to heat and cool. The rooms are still not fully completed but I'd be happy to post pictures if you are interested in seeing our solution.

Beagles- I want to see your pictures! :)

I think I may have posted variations of these already, but here you go.

Conservatory:

This is what the room is modeled after:

Sunroom:

From the outside (sunroom on left)

What do you do in a 'sunroom' that you can't do in a living room? Our LR and DR have a total of nine French doors on the south. Another pair of French doors on the east side of the DR opens to the screened porch (w/skylights in the eastern roof angle). We don't live in an old, cold stone house in Edinburgh. This is plenty of sun for me. People look at our screened porch and ask if we plan to make a sunroom out of it. No, we don't.

This makes me think of the whole 'pantry' idea. Every new house has to have a closet called 'Pantry'. Why? Aren't there enough upper cabinets in the kitchen? Isn't there a back hall with storage? Does every homeowner need a complete 'backup grocery store' in the house? Early homes had pantries because there were no cabinets in the small kitchens and/or the home was miles from a store. (Should we reintroduce 'root cellars'? lol)

Chisue- I think we should reintroduce root cellars, depending on where you live and what you need. I want a huge pantry (not a little closet) because I live on a farm and need a lot of storage. When you only shop a few times a month, it won't all fit in a couple of upper cabinets.

If you live in an area, where you can have nine french doors and don't worry about a heating bill, that's wonderful! In colder climates (maybe not Ediburgh, but close) then a sunroom offers a lot more light than most other rooms.

In your situation, I'd keep the screen porch, too! A sunroom doesn't have the same feel. In fact, I hope to have both :)

Beagles- Your pictures are beautiful! Your entire house is going to be amazing, but the conservatory is my favorite space. It has a fireplace and bookcases, right? I can just imagine, curling up with a good book and watching the snow fall. What a romantic/cozy/wonderful space :)

No fireplace in the conservatory :( There wasn't space. It is in the front of the house right off the foyer and the bookcases and door to our bedroom are on one wall, opening to foyer on another and windows on other two. Plus, everyone vetoed it when I said we should try to fit one in somewhere because we already have multiple fireplaces. There is a fireplace in the sunroom though. That is probably where I will sit more often because it can be totally closed off with french doors so the dogs will be able to be in there with me but not escape to other parts of the house on their own.

chisue our living room has just as many windows and doors as our sunroom. It is, however, bigger and less cozy and more open to the rest of the house and serves a very different purpose from our sunroom.

When we organized our house, the more formal parts are towards the front and more open. The great room, dining room, foyer, and conservatory all flow into one another and are just separated by arches. Towards the back off of the kitchen, we have a smaller cozy "gathering room" and sunroom which can be more private and closed off and cozier. It works for us and is a nice combination of open floor plan and not-open floor plan. It is a lot of different sitting rooms for 2 people and 2 dogs, but I work at home and so I am home ALL day and I wanted to have a variety of places to move around so I don't get bored :)

"I think we should reintroduce root cellars" - lavender_lass
I totally agree lavender_lass!

We are building the home I've spent years designing in my dreams. And it has a cellar (root and wine) and a walk-in pantry, not just for foodstuff but also for those serving platters and chafing dishes and service for twenty that we may only use ten times a year but have to store the other 355 days!

Having lived in houses designed by someone who obviously didn't entertain (or have houseguests), I want to have every kind of storage I can think that we'll need; food; serving; linen; cleaning; holiday decorations; gardening; seasonal clothing; memorabilia; filing/paperwork, and those stupid boxes of 7 years of tax returns!

We're going to have an attic and a walkout basement/man cave gameroom with cellar. And a garage with room for cars AND bicycles, motorcycles, skiis, surfboards, snowboards, and hopefully anything else we may need room for!

And it has a sunroom on the north side of the house (coolest side in the Southern California summers), deciduous trees, a glass roof, potting shelves, a sink, hose, and a brick floor with drain. It also has a gas fireplace and radiant floor heating to be cozy in the SoCal winters.

We are finalizing the plans with the architect, so if anyone can think of any storage needs I've overlooked, please tell me! Thank you.

that sounds awesome! I'd love to see your house plans!