Four season sunroom
One of the choices that you must make when deciding upon what type of sunroom addition to build or have built is whether it is a three or four season sunroom. The term literally means being able to use the sunroom comfortably throughout all four seasons of the year.
The choice is largely determined by how much of the year you would like to use the sunroom and the location of your home.
Northern Locations
The main issue here is the cold weather during the winter. In order to be able to utilize the sunroom during the winter it will need some form of heating. This heating could be a separate portable unit, wall mounted air conditioning or maybe an extension of your existing home heating system. In order to prevent all of this heat escaping, at a fast rate and vast expense into the atmosphere, the sunroom will have to have been designed with heat insulation in mind. This will mean insulating the walls and ceiling framework and glass to prevent heat transfer by conduction through it. If these things are considered then a four season sunroom is possible in a colder climate.
Southern Locations
Whilst the winters may be mild and maybe mean long pants are worn instead of shorts, the summers can be very hot, even more so under glass. It is the summer season that is of most interest for the design of a sunroom here. Without proper sunroom cooling design, which can take the form of air ventilation, air conditioning, window blinds or sunroom shades or partially blocking solar coatings on the windows and ceiling, the room is likely to get too hot to use. If these things are considered then a four season sunroom is possible in a hot climate.
Temperate Locations
Here is probably the only place that can get away with having a sunroom design that will not get too hot in summer or too cold in winter. If there are such places on Earth then let me know and I'll move there. I know my sunroom gets too hot in summer and too cold in winter!
Three season Vs Four Season Sunrooms
Why would anyone not build a four season sunroom? Well just down to cost. Having provision for heating the room and the associated insulation for the sunroom is not free. Also solar coatings on the glass or blinds and air conditioning again doesn't typically come at a very low price. It will probably be noticeably cheaper to build a three season sunroom than a four season one.
Conclusions
Your sunroom addition manufacturer or supplier will be able to advise you of what is available to make your sunroom usable all year round no matter what your location is.