In Hawaii, heat pump installers typically recommend air-source heat pumps as they are optimal in warm climates. When properly installed, they can deliver up to three times more energy to your home than the energy it consumes. Geothermal, while gaining interest, is only currently installed on the big island of Hawaii. Air-source heat pumps pull air from the homes exterior, while geothermal heat pumps draw heat from the ground.
While Geothermal heat pumps are more expensive to install, maintenance is less as they are installed underground and largely removed from the elements. Furthermore, they use much less energy than other heating systems and are very efficient at cooling homes. This of course saves money and energy and reduces air pollution.
Air-source heat pumps are cheaper to install, but perform better in cold to mild temperature climates.