Are 4 season sunrooms worth the cost?" Starting at $6,999 installed, yes – but only if built correctly. RT Louver Pergola provides aluminum frames, 2-year electronics warranty, 10-year structure warranty, and fast installation within 2-3 weeks. Their 4 season sunrooms include hidden fasteners, powder-coated finishes, and multiple color options. Delivery charges apply based on location. Book a free online design session to see your custom enclosure before committing. Serving Ajax, Oshawa, Toronto, Hamilton, London, Ottawa. Smart homeowners choose 4 season sunrooms that last.