The Heat Network Technical Assurance Scheme (HNTAS) establishes minimum technical standards for heat network design, construction, and operation. The HNTAS consultation closes 15 April 2026. Once mandated, heat networks must demonstrate compliance with the scheme's key performance indicators.
HNTAS defines performance KPIs across several categories including heat supply reliability, return temperature performance, metering accuracy, and HIU commissioning standards. Networks must collect and report data against these KPIs to demonstrate ongoing compliance.
Proper commissioning of Heat Interface Units (HIUs) is fundamental to HNTAS compliance. Poorly commissioned HIUs are the leading cause of high return temperatures and network inefficiency. CIBSE CP1 defines the commissioning procedures that heat networks must follow, including flow rate and temperature recording, differential pressure measurement, and VWART tracking.
HNTAS commissioning KPIs include CC-KPI-09 through CC-KPI-13 and commissioning items 6.4.2 through 6.4.9.
HNTAS becomes mandatory once DESNZ finalises the Code. Heat network operators should begin preparing now by ensuring their HIU commissioning records are complete and their network performance data is being collected in line with KPI requirements.
Use the HIU Commissioning Tool