Combination with a solar thermal DHW system is not ideal, since this means not only a higher additional investment for the DHW heating, but also lower annual efficiency with the heat pump. On the other hand, connection to a photovoltaic system, which supplies the electricity for the air source heat pump, is a very good solution. All OCHSNER air source heat pumps are Smart Grid-ready, i.e. set up for use of self-generated electricity or taking advantage of cheaper off-peak tariffs.