The indirect method means that the primary district hot water from the energy centre is separated from the heating circuit with a plate heat exchanger. This requires a circulation pump and pressurisation unit to circulate the space heating water through the radiator or underfloor heating circuit.
From a user point of view, an indirect HIU is particularly relevant if there are concerns about burst pipes and possible water damage. In this case the primary district heating is separated from the heating circuit with a plate heat exchanger so the leakage from a burst pipe will be kept to an absolute minimum.
Indirect HIUs are flexible solutions which are suited to multi-dwelling high rise or wider housing developments. They provide residents with all the benefits of having their own boiler, but with none of the costly drawbacks.
Read more on Heat Interface Units.