I've given 5 stars because I could not give 4.5. The whole process of having a Stiebel Eltron heat pump and SolarEdge solar PV installed was, in the end, very successful, and I am 100% delighted with the result and quality of the workmanship but there were a few niggles along the way. Probably the thing I found most difficult to deal with was scheduling and arranging installer visits to coincide with the building modernisation work that was being done at the same time. This allowed the equipment to be fitted into the fabric of the house but I found it very difficult to manage installer appointments that were often delayed or arranged with less than 24 hours notice and the installation was broken down into quite small chunks requiring many installer visits. Synchronising these changing and fragmented visits with all my other site contractors was a nightmare. Of course none of this was helped by the pandemic. However the the system provided for both heat pump and solar is top notch and works flawlessly.