Understanding HIU Error Codes: A Complete Guide for London Residents Heat Interface Units (HIUs) play a crucial role in modern apartment buildings across London, especially in developments connected to district heating systems. These units act as a bridge between a central heat source and individual homes, ensuring efficient heating and hot water supply. Read More : https://www.ekonty.com/articles/understanding-hiu-error-codes-a-complete-guide-for-london-residents