Dometic DFSDH20111 Furnace; DFS Series; Electric/ LP; 18,000 BTU; Single Stage; Side Or Bottom Ducted; 12 Volt DC; Small Size; 12 Inch Width x 7 Inch Height x 20 Inch Depth; Access Doors And Thermostat Sold Separately; Existing Cut Out Should Be Measured To Ensure The New Dimensions Will Fit Attributes BTU Level: 18000 BTU Discharge Type: Bottom/ Side Type: LP Gas Stage: Single Ignition Type: Electronic Ignition Width: 12 Inch Height: 7 Inch Depth: 20 Inch With Access Door: No   Product Description Engineered for easy maintenance and superior air delivery. Its compact size offers installation convenience. The Dometic Medium Furnace has a redesigned, durable stamped steel door. Features & Benefits Horizontal Or Vertical Configuration For Flexible Installation Low-Profile, Compact Design Quiet Operation Thanks To Reduced Air Turbulence Features 12 Volt DC Powered Unit One-Piece Tubular Design Delivers Efficient Heat Transfer And Airflow Distribution Built-In Soft Start Reduces Jarring Startup Noise Limited 3 Year Warranty