The UK Government's mandatory framework for heat network operators. If you supply heating or hot water to multiple properties from a shared system, this affects you.
Scheme Status
Active & Mandatory
In force from 1 January 2025
What is HNTAS?
Everything You Need to Know About Heat Network Compliance
HNTAS is the Heating Network Technical Assurance Scheme â a UK Government-backed mandatory framework setting standards for how heat networks must be designed, operated and maintained. Here's what it means in plain English.
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What is a Heat Network?
A heat network is any system where heating or hot water is generated centrally and distributed to multiple buildings or units through shared pipework. If this describes your building â HNTAS applies to you.
âApartment blocks with a shared boiler or heat pump
HNTAS sets the technical standards your heat network must meet across six key areas:
âMinimum efficiency standards for heat generation
âMandatory metering of heat to each property
âAccurate billing based on actual consumption
âConsumer protection rights for residents
âAnnual reporting of performance data to Ofgem
âMaintenance standards and response time obligations
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Who Regulates It?
Ofgem is the designated regulator for heat networks in Great Britain. The Heat Network (Metering and Billing) (Amendment) Regulations 2024 came into force on 1 January 2025 â significantly extending the scope of operators who must comply. Failure to comply can result in enforcement action, fines and consumer redress obligations.
Your Obligations
What You Must Do as a Building Owner or Operator
If you own or operate a heat network â whether you are a landlord, housing association, developer or facilities manager â here are your eight legal obligations under HNTAS.
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01
Register Your Heat Network
You must register your heat network with the scheme administrator. This applies to all networks supplying two or more end users â including landlords, housing associations and developers.
âRegister with HNTAS scheme administrator
âProvide full network and operator details
âDeclare metering and billing arrangements
âUpdate registration if any details change
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02
Install Individual Heat Meters
Every flat, unit or building connected to your network must have an individual heat meter. Meters must be accurate, tamper-proof and MID-compliant, enabling billing based on actual consumption.
âFit individual heat meters to every connected unit
âEnsure meters meet MID accuracy standards
âEnable remote meter reading where possible
âKeep installation and calibration records
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03
Bill Based on Actual Consumption
End users must receive bills based on metered consumption â not estimates or floor-area apportionment. Bills must be issued at least annually with a full breakdown of units, tariff and standing charges.
âIssue bills based on metered consumption only
âBill at least annually (quarterly recommended)
âShow full breakdown: units, tariff, standing charge
âProvide comparison against previous period
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04
Publish a Customer Charter
You must have a published customer charter setting out resident rights, complaint procedures, fault response times, planned maintenance notice periods and full operator contact details.
âWrite and publish a customer-facing charter
âInclude complaint and escalation procedures
âState fault response time commitments
âDisplay emergency and general contact details
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05
Meet Minimum Efficiency Standards
Your network must meet minimum energy efficiency standards. Network heat loss must be within acceptable limits and primary generation equipment must operate at defined efficiency levels.
âAssess network heat loss vs HNTAS benchmarks
âEnsure boilers and heat pumps meet efficiency targets
âCommission an annual technical performance review
âDocument and address any efficiency shortfalls
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06
Report Annually to Ofgem
Operators must submit annual performance data to Ofgem covering energy input, heat delivered, network losses, billing complaints and consumer satisfaction. Records must be kept for six years.
âSubmit annual data return to Ofgem portal
âReport energy input vs heat delivered
âDeclare billing complaint volumes
âRetain records for a minimum of 6 years
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07
Maintain Your Network to Standard
All components â pipework, HIUs, metering, controls and generation plant â must be maintained to manufacturer and HNTAS standards with a documented PPM programme.
âImplement a documented PPM programme
âService HIUs annually as a minimum
âInspect and test metering at defined intervals
âKeep full maintenance and service records
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08
Notify Customers of Changes
Customers must receive advance notice of planned maintenance interruptions, tariff changes, billing methodology changes and any significant changes to the network or its operation.
âGive 30 days minimum notice of tariff changes
âNotify customers of planned outages in advance
âCommunicate changes to billing methodology
âProvide written notice of significant changes
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Consequences of Non-Compliance
Ofgem has enforcement powers including financial penalties, compliance orders and consumer redress requirements. Non-compliant operators may also face difficulties with building certifications, sales or lettings. Acting now is far simpler than responding to an Ofgem investigation.
How Zircon Helps
We Make HNTAS Compliance Straightforward
Zircon's mechanical engineers have delivered heat network projects from design through commissioning and ongoing compliance. We understand what Ofgem expects â and how to achieve it efficiently.
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Heat Network Design & Installation
Design and build of communal and district heating â pipework, HIUs, energy centres and metering aligned with HNTAS standards from day one.
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Metering & Commissioning
Supply, installation and commissioning of individual heat meters to MID accuracy standards with remote reading and full documentation.
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Annual Performance Reporting
We help compile and submit your Ofgem data returns â energy input, heat delivered, network losses and billing performance.
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HIU Servicing & PPM
Annual planned preventive maintenance for HIUs, pipework, metering and controls â with full service records to evidence your compliance.
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Compliance Reviews
Not sure where you stand? We conduct independent technical assessments against HNTAS requirements and produce a clear action plan.
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Ongoing Support
From initial registration through annual reporting â our compliance team answers questions, reviews documentation and supports Ofgem interactions.
Not Sure Where to Start?
Talk to our HNTAS team. We will assess your current position, explain your obligations and give you a clear, practical roadmap â with no jargon.