Variable speed units are indeed more efficient and will save you about twenty bucks a month in electricity, however they are a LOT more complex, have many more printed circuit boards and are considerably more expensive to buy. The “boards” may be free with some manufacturers, but the service calls are not $$$$.
VFDs will reduce/eliminate the start up surge & flickering TVs and you can control the speed of the compressor, so most of the benefits of variable speed units are reaped with a very reliable, time tested and relatively inexpensive over the counter VFD controller. If you have single phase 220 our VFD units will have three phase compressors in addition to the VFD, so the surcharge is relatively small.
Self Contained Water Cooled Chillers
Self Contained Air Cooled Chillers
Chillers Water Cooled
Chillers Air Cooled