Heat Interface Units FAQs

Heat Interface Units FAQs

What’s Inside an HIU?

At its core, an HIU consists of several key components that work together to safely and efficiently transfer heat from the central heating network to the property’s heating and hot water systems. If you are maintaining or servicing a HIU, here is what you can expect to find and what each component is responsible for:

• Primary heat exchanger: Always present, it’s the core component that transfers heat from the central network to your heating circuit without mixing the water supplies.
• Common in HIUs designed to provide domestic hot water (DHW) separately from space heating, to keep potable water safe and separate. Some simpler HIUs might combine this function or rely on other methods.
• Control valves: Yes, these are integral for regulating flow and pressure to maintain consistent heating and hot water delivery.
• Thermostatic mixing valve (TMV): Almost always included for safety, especially on the domestic hot water side, to prevent scalding by controlling temperature precisely.
• Pumps: Many HIUs have built-in circulation pumps to move water efficiently through the property’s heating system. Some may rely on external pumps, but built-in is common.
• Metering devices: Usually integrated, since one big HIU advantage is individual heat metering for fair billing and monitoring.
• Controls and sensors: Definitely included to manage system performance, temperature, flow, and sometimes allow remote or smart control integration.

Are HIUs Easy to Install & Maintain?