Electrician and plumber. Refurbing my home. Have now installed new A rated boiler, a 300 litre heat store, under-floor heating, solar heating and multi-fuel stoves. Unable to install cavity wall insultion as walls are 9" solids. Experimenting with batonned, insulated and dry wall lining.
Solar heating flow pipe to be as close to your hot water heat store as possible. I use an aluminium heat exchanger to extract the heat from the solar flow, and am getting a 20C diff. between the flow and return on the exchanger. I chose Barilla Solar as my solar heating components supplier. Strongly technical, with no BS. They have test rigs always on evaluation. I like them. Good prices too.
I put together my own components for the underfloor heating system, to choose best of breed. Have installed clay blocks on the floor rather than concrete to speed up the heating response times; now 20 mins.