How big? Are you going to heat it?

About 20' to 30' long, 12' + wide, depending on prices. Not going to heat it. I'm planning to open the bedroom windows for some supplemental heat for the house during the day. And use a corner for seed starting in the spring.

My covered porch is 18ft by 10ft on the south side of my house. It provides about 80% of my heat in winter and I'm growing blueberry and fig inside during the day.

In order to get heat from the sunroom into the house you either need a fan or the proper opening for natural heat flow. Just opening a couple windows will not work unless one is near the top of the sunroom and one near the floor.

Mine works by opening a door, about 7ft tall, near the top of the sunroom. The floor of the house is about 3ft higher than the floor of the sunroom. This allows heat to flow in the top of the door and cool air from the house to flow out the bottom of the door. A natural circulation sets up and heats the house 50ft from the door.

A fan in one window with return flow out another window would work. The higher the window the better because the hottest air is near the top of the sunroom.

Here is a link that might be useful:

Yes, I have one. It's twelve by 24 and quite tall. It's not a fancy sunroom, but a commercial lean-to g'house with poly carb panels. It runs along one ell of our L-shaped house and the windows of that ell downstairs open to it, as well as three doors.

We built it to take the place of a porch when we tore it down,and to provide a buffer zone against the outside in winter. To pick up a little solar gain and to be a transition area/mud room because we are gardeners.

I'm a little concerned if this room had full south exposure. It will surely be a heat sink in sunny winter days, but it'll be an oven in sunny summer days without extraordinary ventilation.

Don't get me wrong. It's a wonderful addition to have in winter time and we use it for a multitude of purposes and enjoy having ferns and fountains and an open back door when the snow is flying, but any savings in heat can quickly go out the window if it increases cooling expenses. Passive ventilation is not enough for us, it needs shading and air exchanges. It's may also be unwieldy if you don't have direct access to it from the house, and need to go outside to get into it.

Agree with calliope, my porch is covered with poly only from mid October until mid April. During summer it's an open porch.

I'm looking for one that would have removable panels to keep it cool in summer.

wertach:

That's called poly. I built and covered mine for about $300. I'm on the second poly after 6 years. My heat savings have run in the thousands over that period.

i'm having a 8x13' lean to style being installed by Four Seasons sunrooms right now. From what I understand it is essentially a cheap sunroom with vents etc. I'll post pictures when done.