The Energy Knight?? Mini-Split System provides solid quiet cooling or heating and cooling. With a design that includes outside compressor placement, sounds are kept outside and out of earshot. The outdoor unit features solid, pre-painted steel for years of corrosion-resistant operation. With the split outdoor unit, you now have the use and view from a window blocked by a traditional room air conditioner. Installation requires only a small 2-3/4 inch hole for connecting the outdoor and indoor sections. In the indoor unit there is an easy to see self diagnostic light and test key allowing quick identification of any operating problems.