Building a sunroom can be a great way to add extra living space to your home. When deciding on the size, you'll want to take into account the amount of sunlight your home gets as well as the size of the room you're adding it to. A sunny south- or west-facing room is ideal, but if your home doesn't get a lot of natural light, you can still make use of a sunroom by installing artificial lighting. When calculating the size of your sunroom, allow for at least eight feet of width and length for each person who will regularly use it. And don't forget to leave enough space for furniture and storage!

A good size for a sunroom is about 10 feet by 12 feet. But it really depends on how much space you have and how you want to use the sunroom. If you want to use the sunroom mainly for solar heating, then it should be as big as possible. But if you want to use the sun room mainly for relaxation or light storage, then a smaller size might be better. Also, keep in mind that a larger sunroom will require more construction materials and will be more expensive to build.