Mini Splits – small inverter driven split system heat pumps are gaining market share rapidly. They claim the highest efficiencies of any compressor-based heating and cooling systems, and they are relatively inexpensive. The phrase 'mini split' calls to mind the typical wall head we’re all used to seeing. However, this category of equipment includes several different system types for both residential and commercial applications. This class will provide an overview of the most common systems installed in residential, multifamily, and light commercial applications. The pros and cons of the various equipment types will be discussed as well as the relative efficiencies available for each system. We will also review how these smaller systems provide advantages for mechanical system design and layout. Finally, we will discuss installation best practices including line set construction and leak management. There is clear evidence that refrigerant release poses a significant hazard to our environment we will be discussing how to minimize this issue. Finally, we will look at the new refrigerant options that are entering the marketplace.