Independent lab testing confirmed that Advent consistently averages 10% greater cooling capacity than the current 15K ratings when tested to the Air-Conditioning and Refrigeration Institute (ARI) standards. Users will gain more BTU output per unit with the 15K averaging 16.5K BTU resulting in the ability to cool a larger area in a shorter amount of time. The Advent 13 500 BTU roof-top high-efficiency air conditioner was designed specifically for the rigors of the RV lifestyle. Backed up with a No-Hassle 2-year Warranty the system is easy to install and operate fitting into a standard 14 1/4″ x 14 1/4″ vent opening for easy replacement of your existing unit. Premium features include additional evaporator cooling fins offering higher cooling efficiencies; An extremely rigid frame consisting of a composite of foam and metal parts allowing for quieter operation; Premium extra-thick water seal gasket keeping moisture from leaking into the RV; Removable and washable filters that keep the interior clean and free of debris; Motor overload protection for longer life; Non-ozone depleting environmentally-friendly refrigerant. Ducted or non-ducted ceiling packages and Heating Element options are available. With purchase of separate adapter kit the Advent can replace select Coleman and Carrier roof top units. Roof unit dimensions are 35.1″ L x 29.9″ W x 13.2″ H.