How Does a Kirkland Mitsubishi Split Heat Pump Work?

When evaluating a potential new heating and air conditioning system for your home, have you considered a Kirkland Mitsubishi Split Heat Pump? While the name tends to be intimidating, the fact is, the simple elegance of the system is easily understood. As its name indicates, the heating portion and the cooling portion of the system are split; the outdoor unit which houses a heat exchanger (coil) and compressor, while the indoor unit houses a coil and fan.


In reference to the above diagram, representing a typical set-up for a basic split system heat pump, the legend is as follows:

  • A — indoor compartment
  • B — outdoor compartment
  • I — insulation
  • 1 — condenser
  • 2 — expansion valve
  • 3 — evaporator
  • 4 — compressor


The indoor unit fan circulates conditioned (heated or cooled) air through your home’s ventilation system. Freon gas passes through the copper piping that connects the indoor and outdoor units. This circulating freon gas acts as a coolant between the inside and outside coils, by absorbing heat from the air.


As outside air moves over the coil, the freon gas absorbs its heat. By moving through the outdoor unit’s compressor, the gas temperature is increased to 140°F. The heated gas travels through the copper piping to the indoor unit’s coil; at the same time, the fan on the inside unit draws the heated air in through a grill. The heated freon remains in the copper tube within the indoor coil, as the air is passed over it, drawing heat from the coil. The heated air is forced through the house’s ventilation system via ductwork.


Hot air within your home is passed across the inside unit’s coil where the freon gas absorbs the heat. The heated freon gas is drawn to the outside unit’s compressor, then through the outside coil. Moving through the coil, the absorbed heat is then released to the outside air.

As you can see, each process is the direct opposite of it’s counterpart. Heat in the winter is anti-cooling of the summer. With the simple physical exchange of heat through the freon gas, your home is perfectly conditioned all year!