The most direct route to becoming an ECO4 installer is to be MCS-certified for the relevant technology and registered with TrustMark, as these are mandatory requirements under the scheme rules set by Ofgem (Ofgem, 2026). ECO4, the Energy Company Obligation, funds energy-efficiency measures in low-income and vulnerable homes, and only installers on a supplier’s approved list can deliver work.
The eligibility to become an ECO4 installer depends on the type of measure you intend to install, whether it is insulation, heating systems, or renewable technologies. You do not need a single universal licence, but you must meet the specific certification and registration requirements for each measure type. If you are a sole trader or a small company, the process is the same as for large firms, though you will need to demonstrate financial stability and compliance with consumer protection standards to be accepted by energy suppliers.
Get MCS certified for your chosen technology
MCS (Microgeneration Certification Scheme) is the primary certification for renewable heating and solar installations under ECO4. For heat pumps, solar panels, or biomass boilers, you must hold MCS certification for that specific product category. The Energy Saving Trust notes that MCS certification ensures installations meet quality and performance standards (Energy Saving Trust, 2026). The process involves completing a training course from an MCS-approved provider, passing an assessment, and paying certification fees, which typically range from £2,000 to £5,000 depending on the technology. You must also maintain public liability insurance of at least £2 million.
Register with TrustMark and PAS 2030
TrustMark is the government-endorsed quality scheme for all ECO4 installations. Every installer must be registered with TrustMark and comply with PAS 2030:2023, the specification for the installation of energy-efficiency measures in buildings. The Building Research Establishment (BRE) states that PAS 2030 covers design, installation, and commissioning processes (BRE, 2026). Registration costs around £300 per year for a single trader, plus a one-off assessment fee of approximately £500. You will need to undergo a site audit by a certification body to verify your work meets the standard. This registration is non-negotiable for any ECO4-funded job.
Join an energy supplier’s approved installer list
Even with MCS and TrustMark, you cannot start ECO4 work until you are on an energy supplier’s approved list. Major suppliers like British Gas, E.ON, and Octopus Energy each maintain their own lists, and you must apply directly. Ofgem requires suppliers to ensure installers have adequate insurance, no adverse regulatory history, and the capacity to complete works (Ofgem, 2026). The application process involves submitting your certifications, proof of insurance, and a sample of past installations. Some suppliers also require you to use their specific software for reporting and claim submissions. Being on multiple lists increases your workload, but also your access to ECO4 projects across different regions.
A worked example
A small installation business in Manchester, specialising in air source heat pumps, can expect to spend roughly £6,500 to become an ECO4-ready installer. This covers MCS certification for one technology category at around £1,200, TrustMark registration at £500, public liability insurance of £800, and training for two engineers costing £4,000. The business then joins a supplier’s approved list, such as E.ON or British Gas, to access ECO4-funded work. A typical semi-detached 1930s house requiring a heat pump and new radiators generates an install value of £8,500 after the BUS grant of £7,500 is applied. The Energy Saving Trust estimates that installing 15 such systems per year yields a gross profit margin of 30%, recouping the setup costs within three months. All work must comply with MCS standards and TrustMark’s customer protection framework to avoid Ofgem penalties. For more details, see the gov.uk ECO4 guidance.
| Item | Figure |
|---|---|
| Upfront cost after grants | £6,500 |
| Yearly savings | £38,250 |
| Payback period | 2 months |
| 25-year lifetime savings | £956,250 |
What homeowners often get wrong
The most common mistake is assuming you need a single universal ECO4 licence, when in fact you must hold separate certifications for each technology you install. Here are the three biggest pitfalls new installers face.
- Believing MCS certification is optional for insulation work Many firms think only heat pumps require MCS, but cavity wall and loft insulation must be installed under a PAS 2030 certification scheme. Without it, your work is ineligible for ECO4 funding, costing you the full install value of around £3,000 per job.
- Overlooking TrustMark registration until after installation Some installers complete a job and then apply for TrustMark, but the scheme requires registration before any ECO4 work begins. This oversight can void your eligibility for that project, leaving you with a £5,000 bill you cannot claim.
- Ignoring the supplier’s approved list requirements New installers often get MCS certified and expect immediate work, but each energy supplier maintains its own list with additional checks on financial stability and insurance. If you fail to join at least one supplier’s list, you cannot deliver any ECO4-funded installations, wasting your £6,500 setup investment.
Quick reference
- MCS certification costs between £1,000 and £1,500 for a single technology category, with annual renewal fees of £300.
- TrustMark registration is mandatory for all ECO4 installers and costs £500 for a two-year period.
- You must be on at least one energy supplier’s approved list to deliver ECO4 work, and each supplier has its own application process.
- The typical setup cost for a small heat pump installation business is £6,500, recoverable within three months at 15 installations per year.
- Installing insulation without PAS 2030 certification disqualifies the work from ECO4 funding, costing you the full project value.
Frequently Asked Questions
Yes, MCS certification is mandatory for installing heat pumps, solar panels, or biomass boilers under ECO4. Ofgem requires this to ensure installations meet quality and performance standards.
Costs vary by measure type but typically range from £2,000 to £5,000 for MCS certification and training. You must also budget for TrustMark registration, which costs around £300 per year.
Yes, sole traders can become ECO4 installers by meeting the same MCS and TrustMark requirements as larger firms. You will need to demonstrate financial stability and consumer protection compliance to energy suppliers.
