What housebuilders & developers need to know as regulation approaches.
Josh Collins – Heat Networks Manager, Altecnic
With regulation of heat networks moving closer, the Heat Network Technical Assurance Scheme (HNTAS) is set to become a defining feature of how communal and district heating systems are designed, delivered and assessed in the UK. Developed by the Department for Energy Security and Net Zero (DESNZ), HNTAS will introduce mandatory technical assurance requirements aimed at improving consistency, efficiency and consumer outcomes across the sector.
For housebuilders and developers, particularly those delivering high-density, mixed-use or regeneration schemes, understanding HNTAS is becoming increasingly important. Below, Josh Collins, Heat Networks Manager at Altecnic, answers the most common questions surrounding the scheme.
What is HNTAS and why is it being introduced?
HNTAS is a technical assurance framework designed to raise the standard of heat network delivery across the UK. While heat networks play a key role in meeting net-zero targets, performance across existing schemes has been uneven. Issues such as excessive heat losses, high flow temperatures, poor commissioning and variable resident comfort have all been widely reported.
HNTAS aims to address these challenges by setting clear, measurable technical standards that apply across the full lifecycle of a heat network. Rather than focusing solely on design intent, the scheme places emphasis on verified performance, accountability and long-term outcomes for consumers.
When will HNTAS come into force?
DESNZ is currently developing the scheme and its supporting technical documentation. Pilot projects began in summer 2025, with formal implementation anticipated in 2026. Once the framework is live, Ofgem will take on regulatory oversight of heat networks in England and Wales, using HNTAS as a core compliance mechanism.
While the scheme is not yet mandatory, developers progressing schemes now should be planning with HNTAS requirements in mind to avoid redesign, delays or non-compliance at later stages.
Which projects will HNTAS apply to?
HNTAS is expected to apply to both new and existing heat networks, although requirements may differ depending on project type and lifecycle stage. For new developments, HNTAS will influence everything from early concept design through to post-occupancy performance reviews.
Existing networks may also be assessed under the framework, particularly where performance issues are identified or upgrades are planned. For developers with long-term asset ownership or phased developments, this makes early alignment with HNTAS principles especially important.
What does “technical assurance” actually mean?
One of the most significant shifts introduced by HNTAS is the move away from single-stage compliance toward lifecycle assessment. Networks will be reviewed at several key stages, including:
- Pre-design, to ensure proposals align with performance objectives
- Pre-construction, to confirm specifications and layouts meet HNTAS criteria
- Pre-operation, to validate commissioning quality and system functionality
- Post-operation, with performance reviewed after two years of live operation
This approach ensures that systems not only look compliant on paper, but also deliver the efficiency, reliability and comfort expected in real-world use.
How will HNTAS affect design and specification decisions?
Although heat network design is often led by M&E consultants, HNTAS brings wider project decisions into sharper focus. Factors such as plant room locations, riser routes, pipe lengths and service zone coordination all directly influence heat losses and system efficiency.
For developers, this reinforces the importance of early, coordinated design and informed specification. Products and components will increasingly need to demonstrate independently verified performance, rather than relying on nominal ratings or untested claims.
Heat Interface Units (HIUs), for example, play a critical role in determining domestic hot water performance, return temperatures and resident comfort. Under HNTAS, specifying HIUs with proven, independently tested performance data will significantly reduce compliance risk.
What changes for commissioning and handover?
Commissioning has historically been one of the weakest links in heat network delivery, and HNTAS directly addresses this. Robust commissioning evidence will be required to demonstrate that systems operate as designed and that controls, metering and balancing are correctly implemented.
This means developers should expect greater scrutiny of commissioning strategies, clearer documentation at handover, and better provision for access, testing and ongoing monitoring. While this may require more upfront coordination, it significantly reduces the risk of costly post-occupancy issues and resident complaints.
Who is responsible for HNTAS compliance?
HNTAS is designed to encourage shared responsibility across the project team. While developers retain overall accountability for compliance, designers, contractors and product manufacturers all contribute to the assurance process.
Clear roles, defined responsibilities and good-quality evidence will be essential. Working with experienced consultants and suppliers who understand HNTAS requirements can help streamline approvals and reduce risk throughout delivery.
How does HNTAS benefit developers?
Although HNTAS introduces new requirements, it also offers clear benefits. Better-performing heat networks lead to lower operational costs, improved resident satisfaction and stronger long-term asset value. For developers retaining ownership or management responsibility, these outcomes can significantly reduce reputational and financial risk.
In addition, schemes aligned with HNTAS principles are better positioned to meet wider sustainability objectives, support planning requirements and respond to increasing scrutiny around building performance and consumer protection.
How should developers prepare now?
Preparation starts with awareness. Developers should be engaging with project teams early, ensuring that heat network strategies align with emerging HNTAS expectations. This includes reviewing specifications, questioning performance assumptions and prioritising independently validated products.
Training and CPD also have a role to play. The Building Engineering Services Association (BESA) has been appointed as the HNTAS Shadow Training Provider, developing courses to support industry understanding as the scheme evolves.
Final thoughts
HNTAS represents a significant step change in how heat networks are delivered and assessed in the UK. For housebuilders and developers, it signals a move toward greater transparency, accountability and performance-led design.
By understanding the scheme early and embedding its principles into project delivery now, developers can future-proof their schemes, reduce risk and deliver heat networks that perform as intended for both residents and for long-term business outcomes.