We had a 250l Sanden heat pump HWS installed because the pump controller on our 11 year old gas boosted solar system failed. Since it was installed we have had solar PV installed, the opportunity was taken to get off the gas. Although expensive compared to conventional alternatives for domestic hot water systems, the Sanden system offers a very economical long term solution. The installation was arranged by Pure Electric from their office (in Melbourne) using local tradies - plumber and electrician. Both were very competent, courteous and coordinated, with the job being supervised remotely at every step. So far so good - it is working as advertised.