Some customers who have had Solar PV panels installed have noticed their electricity meter runs backwards.

This means they’re receiving free electricity from their energy company.  However, while households may be reluctant to tell their supplier about this some customers have been landed with additional bills retrospectively.

The problem occurs when the electricity generated by the Solar panels is exported to the grid as part of a scheme called the feed-in tariff (which pays people for electricity they produce at home), making the meter run in reverse

The problem – which occurs mainly with older analogue meters – may be even more widespread than a recent survey of 1,300 users uncovered, as several said they never look at their meter. There are about 400,000 Solar PV installations in the UK so lots of people could be affected.

For most the meter problem has been an unexpected side effect, though some were warned by their Solar PV panel installer that it might happen.

Around 67% of those with meters running backwards have told their energy supplier – more than half of these had their meters upgraded at no extra cost, while a fifth are awaiting a resolution.

If your electricity supply meter runs backwards, it will show a falsely low reading, leading to an inaccurate bill. Because of this financial advantage, some households may have been tempted to stay quiet about the problem, getting free electricity on top of the savings that they are making from their feed-in tariff

The energy regulator Ofgem told us that anyone who notices their meter is inaccurate should contact their energy supplier as soon as possible.

It said: ‘Once the supplier is aware that the meter may not be suitable, it’s their responsibility to take any necessary steps to ensure the meter is appropriate.’

Our advice is to contact your provider as soon as the problem becomes evident and have the fault recorded.  This should prevent any unnecessary retrospective billing