Abstract: A solar boosted heat pump for providing heating or cooling including a heat conducting plate which has an uninsulated rear surface and is exposed to the atmosphere and operates as a direct solar and ambient heat absorber when in its cooling mode. A refrigerant fluid carrying tube is provided in heat transfer relationship with the conducting plate which forms a part of a closed refrigerant flow system having a compressor and a heat exchanger in heat exchange relationship with a heat transfer medium. The plate also includes a sensor for varying the speed and/or the displacement of the compressor dependent on the light incident onto or energy on the plate.