In the residential retrofit application, ductless mini-split heat pumps (DHP) are often reported to hold high-energy savings potential, depending on the system they are supplementing or replacing. However, of late, there have been a number of studies and analyses indicating these energy savings are not being achieved. The primary goal of this project was to determine the most cost effective (lowest cost for the most energy saved) and persistent (e.g. automated, hard to change, etc.) solution for controlling a ductless heat pump in an existing home with central forced air furnace. Various control strategies were tested at the Pacific Northwest National Laboratory Lab Homes to compare the energy savings between the different energy efficient control strategies. A maximum of 40% energy savings was realized by using the ductless mini-split as the primary heat source with the central air conditioning unit as the secondary source.