The UK installed over 180,000 domestic solar PV systems in 2025. Behind every one of those installations sits a stack of compliance paperwork that the homeowner never sees and the installer spends hours completing. MCS certification, TrustMark lodgement, building regulations notification, DNO applications, and EPC updates. For the 3,500 MCS-certified installers in England and Wales, the documentation burden is one of the least discussed costs of doing business.
The Microgeneration Certification Scheme is the gateway to the market. Without MCS certification, your customers cannot claim the Smart Export Guarantee, the Boiler Upgrade Scheme grant, or (in most cases) get the installation recognised by their mortgage lender. MCS certification requires you to lodge every installation on the MCS Installation Database within 10 working days of commissioning.
Each lodgement requires the system design details (panel type, inverter, orientation, tilt, kWp), the commissioning test results, the customer declaration, and the MCS certificate number. The installation database is a web portal. You fill in the fields, upload the commissioning sheet, and submit. It takes 20 to 40 minutes per installation if everything goes smoothly. If you have a query or a correction, add another 20 minutes of back-and-forth.
MCS-certified installers are automatically TrustMark-registered, and every domestic installation must be lodged on the TrustMark Data Warehouse. This is a separate system from MCS. You enter the property details, the work carried out, the compliance documentation, and the customer satisfaction declaration. TrustMark lodgement became mandatory for any work funded by government schemes (including ECO4 and BUS grants) and is increasingly expected by mortgage lenders.
The lodgement takes 15 to 25 minutes per job. It duplicates much of the information you already entered in MCS, but TrustMark has its own format, its own portal, and its own validation rules.
Solar PV installations are notifiable under Part L of the Building Regulations. As an MCS-certified installer, you can self-certify under the Competent Person Scheme, which means you notify your certification body rather than the local authority. But you still have to notify. The notification includes property details, installation date, system specifications, and confirmation that the work complies with Part L and Part P (where applicable).
This is a third data entry exercise for the same installation. Another 10 to 15 minutes per job.
Any grid-connected solar PV system requires notification to (or approval from) the Distribution Network Operator. Systems under 3.68 kW on a single-phase supply can use the simplified G98 notification process. Larger systems require a G99 application, which involves a full assessment of the grid connection and can take weeks to process.
Even the G98 notification takes 10 to 15 minutes to complete. G99 applications can take 30 to 60 minutes to prepare, plus the wait time for the DNO response. There are 6 DNOs in England and Wales, each with different portals and different application forms. If you work across DNO boundaries, you are learning multiple systems.
After installing solar PV, the property's Energy Performance Certificate should be updated. If the installer is also an accredited energy assessor (many are), this means producing a new EPC and lodging it on the EPC Register. If not, the homeowner needs to arrange a separate assessment. Either way, the BUS grant requires an up-to-date EPC, and the EPC lodgement is another data entry task: 15 to 20 minutes for a straightforward domestic assessment.
The Boiler Upgrade Scheme provides a grant of up to 7,500 towards heat pump installations and was extended in 2025. For eligible installations, the installer submits the grant claim through Ofgem's portal. The claim requires MCS certificate details, installation details, customer details, and evidence of the existing heating system. Processing a BUS claim takes 20 to 30 minutes and requires information from multiple sources.
Add it up. A single domestic solar PV installation generates 90 to 150 minutes of compliance documentation across 4 to 5 separate portals. For an installer completing 200 installations per year, that is 300 to 500 hours annually spent on compliance paperwork. At a loaded labour cost of 35 per hour (including employer NIC and overheads for a qualified electrician), the compliance administration for a 200-install business costs 10,500 to 17,500 per year.
That is a full-time hire's worth of admin, or roughly 50 to 85 per installation. On a typical domestic solar PV job with a margin of 1,500 to 2,500, compliance documentation is consuming 2 to 6 percent of gross margin before you account for any corrections, queries, or failed submissions.
Solar design tools like OpenSolar and PVsol handle the system design and proposal. CRM systems like JobNimbus or Tradify handle scheduling and invoicing. But no single tool handles the compliance chain: MCS lodgement, TrustMark, building regulations, DNO notification, and EPC. Installers are copying the same data into 4 or 5 different portals, with no automated cross-check and no single view of compliance status per installation.
Slatewick is building compliance management tools for MCS-certified installers. One data entry, all portals. MCS, TrustMark, building regs, DNO, EPC, and BUS grant claims. Register your interest.
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