Mini-split heat pumps are mechanical devices that move heat from one place to another, and consist of one indoor unit, one outdoor unit and the piping and wiring that connect the interior and exterior components. Heat pumps can provide heating or cooling, with the switch between the two modes accomplished with the push of a button.
Heat pumps run on electricity and typically have heating efficiency levels averaging 300 percent (i.e. A $1 unit of electric input produces $3 of electric heat output) and heat pumps provide heat at about half the cost of oil.