This will take the latent heat from the air at the outside unit and use it to warm up a refrigerant that turns to gas even at low temperatures. This refrigerant gas is then compressed thereby releasing heat that is used to heat the water either for the underfloor heating or for the domestic hot water when the solar thermal panels aren't able to work.
For the rest of the day the house has been resting, waiting for the screed to dry a bit more. The first screeding company will be returning soon to improve the upstairs floor and hopefully remove some of the materials from the front of the house so we can tidy it up. Currently there is D49 mesh and sand everywhere!