Variable refrigerant flow (VRF) is increasing in popularity and Matt Risinger, master builder, is at the Mitsubishi booth and the 2017 International Builders Show with Lauren Hunter to discuss. Risinger has used mini splits for years and was introduced to the concept in Japan 15 years earlier.Most American houses are heated and cooled with the compressor outside that has one or two speeds. As a result, there are uncomfortable areas in the house. VRF units can vary their capacity, be turned up or down, making a huge different in zone systems. There are many more options today including new colors, radiator style units that can be recessed back into a wall, head units, and one called IC 3D, which is more than an occupancy sensor. It can tell there's a warm body in the room and it'll run and when that body leaves for a certain period of time. If you don't want this type of unit on the wall, the technology is available in several form factors, from a normal-looking American box with standard ductwork attached to it, however the engine is still the VRF technology. One can be hung up in the rafters that is small and compact, but still blows air, has traditional registers," but it is sized for one or two rooms. There are many options that will provide comfort and efficiency. .