Solar PV and Battery Records: What Homeowners Must Keep

Installing solar photovoltaic (PV) panels and home battery storage is a significant investment. While most homeowners focus on system output, panel placement, and payback periods, the paperwork generated during installation is just as critical. Without the right technical records and compliance certificates, you may struggle to register for export tariffs, service the equipment, or answer buyer enquiries when you eventually decide to sell your home.

Core certification: MCS and Building Regulations

The foundation of your solar paperwork is proof that the system was installed by a certified professional to national standards. In the UK, the Microgeneration Certification Scheme (MCS) is the recognised quality standard for microgeneration technology. You must receive an official MCS certificate for both the solar PV panels and any integrated battery storage system. Energy suppliers require an MCS certificate before you can apply for the Smart Export Guarantee (SEG) to sell surplus electricity back to the grid.

In addition to MCS certification, your installation must comply with Building Regulations. Solar installations involve both electrical work (Part P in England and Wales) and structural considerations regarding the weight and wind load on your roof timbers. If your installer is registered with a Competent Person Scheme (such as NICEIC or NAPIT), they will self-certify the work and notify your local authority.

• MCS Certificate: Issued per technology (solar PV and battery storage often have distinct certificates).
• Building Regulations Compliance Certificate: Issued via the relevant Competent Person Scheme or local authority Building Control.
• Electrical Installation Certificate (EIC): Demonstrating that the AC wiring, inverter connection, and consumer unit modifications meet BS 7671 standards.

Grid connection paperwork: DNO notification and approval

Any system generating electricity connected to the mains grid must be registered with your local Distribution Network Operator (DNO), the company responsible for the regional power infrastructure. The required documentation depends on the capacity of your inverter and battery system.

For standard residential systems with an inverter capacity up to 3.68kW on a single phase, the installer follows the 'Engineering Recommendation G98' process. This is a fit-and-notify procedure where the installer submits notification to the DNO within 28 days of commissioning. For systems larger than 3.68kW, or complex battery systems with higher discharge rates, prior approval under 'Engineering Recommendation G99' is required before the system can be turned on. In either scenario, you should retain the DNO application, reference number, and formal acknowledgement letter.

Technical documentation, warranties, and commissioning sheets

A solar and battery system comprises components from multiple manufacturers, each with separate warranty terms and technical lifespans. Solar panels often carry product warranties of 10 to 25 years and linear performance guarantees up to 25 or 30 years. Inverters typically carry warranties between 5 and 10 years, while lithium batteries usually come with a 10-year warranty linked to cycle counts or throughput.

To keep these warranties valid, you must retain the installer's original invoice, the equipment serial numbers, and proof of warranty registration with the manufacturers. Your installer should also provide a comprehensive commissioning sheet. This document details string layouts, open-circuit voltages, operating currents, inverter settings, and the exact location of DC and AC isolation switches. Clear schematics and emergency shutdown instructions are vital for routine maintenance and for emergency services in the event of a household incident.

Maintaining a permanent record for the property

Solar installers occasionally cease trading, and paper certificates stored in folders can be misplaced over a 15-year period. Storing digital copies of your MCS certificates, DNO sign-offs, electrical test sheets, and structural calculations ensures you have complete control over your system's history. Using an independent platform like Project Passport allows homeowners to compile all renewable energy documentation alongside standard property records in one permanent location.

When you eventually put your home on the market, conveyancers and prospective buyers will request evidence of grid permissions, electrical safety, and transferable manufacturer guarantees. Keeping your solar and battery paperwork organised on Project Passport from day one eliminates delays, demonstrates thorough maintenance, and protects the long-term value of your renewable energy investment.