Short answer: Ask the seller for the system size, whether there is a battery, the MCS certificate, the grid registration, the warranties and manuals, and any Feed-in Tariff or export tariff details. Check the panels are listed in the fixtures and fittings. Then have the system checked, because the inverter, which lasts around 12 years, is the part most likely to fail.
Questions to ask the seller
The Energy Saving Trust’s advice for buyers lists what you should find out. In plain terms:
- The system: its size in kWp, when it was fitted and whether there is a battery.
- Registration: whether it is registered with MCS, and whether it earns a Feed-in Tariff or an export tariff.
- Fixtures and fittings: check the panels, and any battery, are listed in the sale. Nobody wants to find the panels were meant to go with the seller.
- Paperwork: the MCS certificate, the grid registration, the manuals, and the warranties. Panels usually carry a 25-year performance warranty and a 5 to 10-year product warranty.
- Ownership: that the seller owns the panels outright. Some older “free solar” deals leased the roof space to a company, and that lease will affect you as the new owner.
People on house-buying forums have run into problems with older systems they were asked to pay extra for and panels that stopped working just before completion. Asking early avoids most of that.
Transferring the Feed-in Tariff
The FIT closed to new applicants in March 2019, but existing contracts run for 20 to 25 years, so many older systems in Birmingham still earn it. The Energy Saving Trust says the seller should tell the FIT licensee, the supplier that pays the tariff, that they are moving. You then apply to the same supplier for the remaining payments. Keep a meter reading from the day you move in.
If the system is on an export tariff instead, the Energy Saving Trust says there is usually a change-of-ownership form for export payments. Export tariffs usually need the MCS certificate, which is another reason to get a copy. Can you get SEG payments without MCS? explains why.
Have the system checked
The Energy Saving Trust recommends a specialist check covering safety, the inverter and cleaning. The inverter matters most. The Energy Saving Trust says it needs replacing after around 12 years, while the panels last 25 years or more. A system fitted ten or more years ago may be due one soon.
A check tells you whether the system is producing what it should, whether the inverter is showing faults, and whether the wiring and roof fixings are sound. If something is wrong, you have a figure to take to the seller. Solar panel maintenance explains what a check covers.
If the paperwork is missing
If the installer has closed, MCS says only its helpdesk can access the certificate to amend it. What happens if your solar installer goes out of business? covers the steps.
Adding a battery after you move in
Many buyers want to add a battery to panels that came with the house. If the system earns a FIT, the battery has to be set up so the generation meter only counts solar power. Does adding a battery affect your Feed-in Tariff? explains the rules.
Bottom line
Before you exchange, get the paperwork from the seller, check the panels are in the fixtures and fittings, arrange the FIT or export tariff transfer, and have the system checked so you know the inverter is working. We carry out system checks across Birmingham and the West Midlands. Call 0121 330 1151, 9am to 7pm, 7 days.