(Heat Interface Unit)

Heat Interface Units also known as HIU systems act as a bridge between the central boilers and the heating and hot water systems within a property. These are typically installed within large apartments blocks with multiple homes rather than having to fit each apartment with a boiler.  With an HIU you have one central boiler system which provides heating and hot water to the entire block of flats. This not only saves costs but also maximises the use of space available within each property. The hot water produced by the centralised boiler system is transferred via heat exchangers, to provide each apartment with on-demand heating and hot water. Heat interface units can be designed to work alongside other renewable technologies such as solar PV or air source heat pumps.


HIU Maintenance Services

Most manufacturers’ warranties are only upheld if your renewable technology is regularly maintained, which is why it is important to ensure your heat interface units are serviced frequently by qualified engineers. This will not only guarantee your system’s performance throughout the year and prolong the lifetime of the technology but it will also save you money on repairs as most parts are covered by warranty for approximately ten to fifteen years.  We provide annual planned maintenance contacts, repairs and installations that are carried out by one of our qualified and experienced engineers. We not only provide reactive call outs for our clients signed up to our maintenance contracts but will also attend emergency repairs for clients as well.

HIU Servicing includes the following:


  • Check and clean the strainers
  • Inspect the functionality of the pumps
  • Check the system operating parameters
  • Check and clean the port valves
  • Check for leaks and pressure drops in both primary and secondary sides of the heat exchangers