SOME solar panel firms are behaving like "cowboys" by vastly overstating the potential energy savings to consumers, according to a watchdog.
Which? said an undercover investigation revealed two high-profile companies – Everest and Ideal Solar Energy – potentially breaking the law by using hard sell tactics on the doorstep.
The consumer watchdog investigated 14 companies early this year following a rise in complaints about the industry, asking them to quote for the installation of a solar thermal system at a property in south-east England.
A heating engineer with solar thermal technology expertise was then asked to assess them against industry codes of practice.
Which? also asked a senior trading standards officer to check for misleading claims and hard sell tactics.
It found 10 out of 14 installers exaggerated the potential savings from installing a solar thermal system. An independent expert calculated that such a system would cut about 10 per cent from an annual gas bill, saving around 55 a year, but Ideal Solar Energy quoted savings of 50 per cent and Everest quoted a 43 per cent cut.
Everest claimed the homeowner would save 35,000 over 20 years, described by Which? as a "massive exaggeration".
The watchdog said: "Even if gas prices went up an unlikely 500 per cent, the saving over 20 years would still just be 5,000."
Both companies offered significant discounts if the buyer signed up on the day.
Everest cut its quote of 11,500 to 8,500 if the homeowner agreed to the sale immediately and Ideal Solar Energy dropped its price from 8,690 to 6,520 for a same-day agreement.
Which? chief executive Peter Vicary-Smith said: "Most of the firms in our investigation behaved like true cowboys.
"They promised huge savings that bore no relation to reality, and some really piled pressure on the homeowner to sign up immediately or risk losing a one-off 'special offer'."