This air conditioner is designed to be inconspicuous in architectural spaces. Architects prefer subtle duct-type outlets that blend in, but for cost reasons often use cassette-type units despite disruption to interior design. Surveys of architects reveal significant need for “visually silent” cassettes that harmonize with interiors. Maintaining the cost benefits, ease of installation, and performance of a cassette, this product offers unobtrusive design rivalling duct-types. The four flaps, which can disrupt harmonious design, are coated black to reduce visual impact. The central inlet is louvered to meld with architectural ceilings.