Fresh warnings have been issued over another scam targeting vulnerable people.
Norfolk Trading Standards said residents have received fraudulent letters from companies supposedly offering solar panel health checks.
The letters offer homeowners a free check or service or say that their warranty is due to expire.
Trading Standards and the Solar Trade Association have confirmed the letters are fake and advised residents to not respond to the letter's request to validate their warranty and book a free check-up.
The Solar Trade Association (STA) added that some letters had used their branding or pretended to be from the STA and urged people who received them to be wary.
The organisation said, "This has occurred in the form of letters from the ‘British Trading Solar Association’ offering homeowners ‘free solar health checks’ as well as employment opportunities through freelance jobs sites.
The STA also advised people to ignore the letter or to contact the original supplier of the solar panels for advice.
Trading Standards advice
Norfolk Trading Standards said their advice to customers is to never accept work from an unsolicited approach.
They said, "We advise solar panel owners should always talk to their supplier before allowing any work or ‘maintenance’ to take place on their panels.
"Generally, a solar panel system does not need servicing but it may benefit from being cleaned if the panels are dirty."