Solariums are fully glassed rooms—walls and roof—to maximize sunlight, while sunrooms combine large windows with a solid, insulated roof for balanced light and year-round comfort. In this guide, we compare their construction, energy performance, cost, maintenance, design, and ideal uses. It is often designed for use in every season, depending on your insulation and heating or cooling setup. This type of room blends comfort with versatility, making it ideal for everything from morning coffee to afternoon. A solarium is a type of sunroom addition that is made completely out of glass, including the walls and roof. Sunrooms cost $20,800 to $72,000 on average, while solariums range from $30,000 to $75,000, with some sunroom types offering more affordable options.