HIES is one of only two Chartered Trading Standards Institute approved consumer codes that UK installers can join to satisfy scheme requirements such as the Boiler Upgrade Scheme, sitting alongside RECC (Ofgem BUS Installer Guidance V4.2, 2025). For most of the last decade, MCS certification made membership of one of these two codes compulsory. That changed with MCS's redeveloped installer scheme, which has removed the mandatory requirement during a rolling transition through 2025 and into 2026 (APHC, 2025).
Anyone typing "HIES" into a search bar is usually trying to work out what the scheme actually does, whether it is the same thing as RECC, and which one their business should join now that the MCS rule has loosened. This guide answers that from the installer's seat rather than the homeowner's, covering fees, complaint routes, scheme eligibility and the practical trade-offs between the two codes, because most existing HIES content is written for consumers deciding whether to hire a member, not for installers deciding which code to join.
Key Takeaways
- HIES and RECC are both CTSI-approved consumer codes accepted for the Boiler Upgrade Scheme, but MCS no longer mandates membership of either as of its 2025 to 2026 scheme redevelopment.
- RECC's fees scale by employee headcount, from £226 for sole traders to £2,310 for firms with over 200 renewable energy staff, plus a £100 joining fee.
- HIES protects consumers through deposit protection insurance (up to 25% of contract value, capped at £5,000) and insurance-backed guarantees running two to ten years.
- HIES has logged over 321,000 solar PV installations and 60,000 heat pump installations by its members since 2012.
- A 2020 legal dispute between HIES and MCS over mandatory RECC membership is the backstory behind why installers now have a genuine, unforced choice between the two codes.
What is HIES?
HIES, short for Home Insulation and Energy Systems, is a CTSI-approved consumer code covering the installation of renewable energy and home energy efficiency products across the UK (HIES, 2025). It was founded in March 2012, gained formal Consumer Code status in July 2015, and became an approved Alternative Dispute Resolution authority in August 2018. HIES covers solar PV, battery storage, air and ground source heat pumps, EV chargepoints, biomass boilers and several other technologies.
Installers who join HIES go through an accreditation process before being admitted, and members face ongoing monitoring and annual reviews against the scheme rules and code of practice. The scheme's stated purpose is to give consumers financial protection that survives an installer going out of business, which is a meaningfully different job to MCS's technical certification. In practice, installers often confuse the two because both sit alongside MCS paperwork at the point of sale.
What is RECC and how does it differ?
RECC, the Renewable Energy Consumer Code, was formed in 2006 and has been continuously monitored by CTSI since gaining approved code status in 2007 (Trading Standards UK, 2025). RECC sets standards for marketing, quotations, deposits, contracts and after-sales service specific to small-scale renewable energy installations sold to domestic consumers.
The functional overlap with HIES is large: both are CTSI-approved, both cover solar and heat pump technology, and both were historically linked to MCS certification. The key difference sits in ownership and heritage. RECC is part of Renewable Energy Assurance Limited, a subsidiary of the trade body now known as the Association for Renewable Energy and Clean Technology, giving it closer ties to manufacturer and trade association networks than HIES.
HIES vs RECC: how do the two consumer codes compare?
The clearest way to compare HIES and RECC is side by side on the things installers actually budget for: joining costs, ongoing fees, and what happens when a job goes wrong. Both schemes cover similar installation types and both satisfy BUS eligibility, but the fee structures and dispute processes diverge in ways that affect which one suits a given business size.
- Approving body: HIES: CTSI Approved Code; RECC: CTSI Approved Code
- Founded / code status since: HIES: 2012 / Consumer Code since 2015; RECC: 2006 / Approved code since 2007
- Joining fee: HIES: Accreditation process, no published flat joining fee; RECC: £100 (excl. VAT) one-off application fee
- Annual fee range: HIES: Varies by product and business size; RECC: £226 (sole trader) to £2,310 (200+ staff)
- Deposit protection: HIES: Up to 25% of contract value, max £5,000, 120 days; RECC: Deposit and workmanship warranty protection via insured products
- Redress route: HIES: ADR, mediation, access to an Ombudsman; RECC: Adjudication, arbitration and conciliation via CEDR
- BUS/MCS eligible: HIES: Yes; RECC: Yes
- Parent organisation: HIES: The Integrity Foundation; RECC: Renewable Energy Assurance Limited
How much does RECC membership cost?
RECC charges a one-off £100 application fee excluding VAT, plus an annual membership fee that scales by the number of employees involved in renewable energy activity (RECC Fees, 2026). A sole trader pays £226 a year, while a firm with between seven and twenty-five staff pays £599, rising to £2,310 for organisations with more than 200 renewable-energy employees.
This tiered structure means a two-person installation firm and a fifty-strong regional contractor pay very different amounts for the same protections. RECC also runs a joint membership discount with the Electric Vehicle Consumer Code for Home Chargepoints, so installers who fit both solar and EV chargers can bundle cover for a lower combined fee than joining separately.
What are RECC's membership requirements?
RECC requires Code Members to be certified, or actively working towards certification, to the relevant MCS Installer Standards, and membership can be terminated if that certification is not achieved within three months of joining (RECC Consumer Code, 2026). Members must also offer consumers Alternative Dispute Resolution, a non-negotiable condition of Approved Code Scheme status.
Beyond certification, RECC members must train staff on safeguarding consumers in vulnerable circumstances, display the RECC and CTSI Approved Code logos correctly, and inform every customer about the code and how to access it. On a site visit last year one installer told us the paperwork trail around vulnerable-customer training was the part new joiners underestimated most, since it needs evidencing at audit, not just delivering once.
What complaint process does HIES offer consumers, and why does it matter for installers?
HIES gives consumers access to a free advice line, CTSI-approved ADR, an independent Ombudsman, and free independent inspections where a mediator deems them necessary (HIES, 2026). For installers, this matters because a strong, well-publicised complaints route reduces the number of disputes that escalate to small claims court or negative reviews, and it signals credibility to homeowners comparing quotes.
Deposit protection is capped at 25% of contract value or £5,000, whichever is lower, for 120 days after signing. That cap is worth knowing before quoting large deposits on bigger heat pump or battery installations, since anything above the threshold falls outside HIES's automatic cover unless separately arranged.
Does MCS still require consumer code membership in 2026?
MCS no longer makes Consumer Code membership mandatory under its redeveloped installer scheme, a change that has been rolling out since 2025 and continues into 2026 (APHC, 2025). Installers instead operate under a Customer Commitment document that sets out consumer-protection obligations directly through MCS, with Consumer Code membership now optional rather than compulsory.
Despite the rule change, RECC reported in April 2026 that installers "overwhelmingly renewed" their membership, framing independent redress and deposit protection as distinct value separate from MCS's technical certification (RECC, 2026). For installers doing Boiler Upgrade Scheme work, both codes remain accepted, so the practical decision is now about fit, not obligation.
Why did HIES and MCS end up in a legal dispute over RECC?
In 2020, HIES launched legal action against MCS Service Co Ltd after MCS changed its rules to require installers join RECC specifically rather than any CTSI-approved code, calling the move anti-competitive (Solar Power Portal, 2020). HIES considered referring the matter to the Competition and Markets Authority and Ofgem, arguing installers and consumers deserved a genuine choice of code.
That dispute is the direct reason "HIES vs RECC" became a live search topic among installers, since many businesses were forced to weigh switching codes under a compliance deadline rather than on the merits. With MCS's mandate now removed entirely, the underlying competition question has largely resolved itself in installers' favour, restoring free choice between the two.
Which code should a solar or heat pump installer choose?
There is no single correct answer, since both codes satisfy the same government scheme requirements and carry equivalent CTSI backing. Smaller firms and sole traders may find RECC's tiered fee structure (from £226 a year) more predictable, while businesses already embedded in HIES's installer network may value its longer-standing deposit protection product and Ombudsman access.
Firms doing high volumes of MCS-linked work, including Boiler Upgrade Scheme installations, should weigh which code's audit cadence and paperwork style fits their existing MCS compliance processes, since duplicating admin across two overlapping schemes wastes time better spent on site. Checking TrustMark registration requirements alongside either code is worth doing at the same time, since TrustMark often bundles in free or discounted membership through the code itself.
Closing thoughts for installers weighing HIES against RECC
Choosing between HIES and RECC now comes down to cost structure, existing scheme relationships and how each code's dispute process suits your customer base, rather than any regulatory obligation to pick one over the other. Both remain valid routes to satisfying Boiler Upgrade Scheme and MCS-linked consumer protection requirements in 2026, and both are unlikely to disappear given their decade-plus track records with CTSI.
Whichever code you settle on, keeping deposit protection and paperwork evidence organised alongside your renewable installation paperwork will matter more at audit time than which logo sits on your van. Reonic's installer software can help keep that documentation, proposals and customer records in one place as your compliance obligations shift.
FAQ
Is HIES the same as RECC?
No. Both are CTSI-approved consumer codes covering renewable energy installations, but they are separate organisations with different ownership, fee structures and dispute processes. HIES was founded in 2012 and became a Consumer Code in 2015, while RECC has operated since 2006. Installers can join either, and both currently satisfy Boiler Upgrade Scheme eligibility requirements.
Do I still need a consumer code to keep my MCS certification?
Under MCS's redeveloped installer scheme, Consumer Code membership is no longer mandatory, following a rolling transition through 2025 and into 2026. Installers still operate under MCS's Customer Commitment for consumer protection. Many businesses continue joining HIES or RECC voluntarily for added redress and deposit protection, even though it is no longer a compliance requirement tied to MCS certification.
How much does it cost to join RECC as a small installer?
Sole traders pay £226 a year plus a £100 one-off application fee, excluding VAT. Fees rise with employee headcount involved in renewable activity, reaching £2,310 annually for firms with over 200 staff. RECC also offers a discounted joint membership with the Electric Vehicle Consumer Code for installers who also fit EV chargepoints.
What happens if a customer complains about a HIES or RECC member?
HIES offers a free advice line, CTSI-approved ADR, an independent Ombudsman and free inspections where needed. RECC uses adjudication, arbitration or conciliation, with CEDR handling independent cases the code cannot resolve internally. Both routes are free to consumers and designed to keep disputes out of small claims court wherever possible.
Does the Boiler Upgrade Scheme require RECC or HIES specifically?
Neither exclusively. Ofgem's Boiler Upgrade Scheme guidance recognises both HIES and RECC as approved consumer codes alongside MCS certification for installer eligibility. Government has indicated it may add the MCS Customer Commitment as a further approved route once fully assessed, but as of 2026 both existing codes remain valid options for installers.
