These nine mistakes account for most of the money lost on a UK solar and battery installation, and nearly all of them are made at the quotation stage rather than on the roof. The most expensive is fitting fewer panels to bring the price of a quote down, because the panels themselves are only around 5 to 10% of the total cost of the job. Spirit Energy has designed and installed these systems since 2010, and the same errors still turn up in the quotes homeowners bring in for a second opinion.
