Has anyone had any experience with hybrid heat-pump / gas boilers.
This one Murelle Revolution 30 - SIME : SIME which combines the two energy sources into a single unit. It was used by Wales and West and Western Power Distribution in their trial of balancing the electric and gas systems to achieve lowest CO2 output. However to do that they over rode the boilers control systems and installed a bespoke system.
While they were able to achieve the minimisation of CO2 this could not be done at a cost that was economic for the user.
David Joffe from the Climate Change Committee has had a similar experience. He retrofitted a heat pump alongside his existing boiler but has told me that without the RHI payment it would be too expensive to run in heat pump mode.