One of the terms that you hear if you’re looking to have your porch area enclosed is if you will have a three-season or four-season porch enclosure built. The logic behind this question is simple: if you will be using the enclosed porch area as a true living space, then you will have to consider how weatherproof and insulated the construction will be. This is particularly important if your local area does experience a winter season.
Construction-wise, this will mean that the type of glass and walls that you will use should be able to retain heat in cold weather to within the specifications required by local building codes. Alternatively, this also means that in other climate types, your enclosure should also be able to withstand the external environment, such as exposure to sunlight, heat, and rain.
As it is, your intent on making the enclosed porch a true living space, and the cost of it will determine if you will use building materials and codes that will qualify it as a year-round usable living area.