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Solar panel cold calls to watch out for

Do solar panels really need a health check? Can cold callers tell if your solar pv is faulty? Don't be caught out by these common calls

Solar panel cold calls to watch out for

More than half of solar panel owners in our survey have been approached by a cold caller. Some were trying to sell them something unnecessary or even claiming something likely untrue.

The most common cold calls about solar panels were:

  • Offering a free health check for the solar panels
  • Selling an optimiser or voltage optimiser
  • Claiming the inverter needs changing

That’s based on our survey in June 2021 of 1,116 Which? Connect panel members with solar panels.

Some product offers can be legitimate and worthwhile – but sometimes they’re being mis-sold.

Think carefully about the claims made about any product you’re being offered, and work out if it will benefit your system. A cold-caller on your doorstep or phone doesn’t give you time to think things through.


See our solar panel brand reviews.


Cold call 1: Free health check for your solar panels

Solar panels on the roof of a house

This was by far the most common cold call solar panel owners told us about – 44% have been approached about this.

Technical faults with solar panels are rare. Nearly seven in 10 of those in our survey have not had a fault with their system. Some have owned theirs for more than a decade.

Your solar panel installer should have told you how to check that your system is working correctly and any maintenance or cleaning you need to do.

Solar Energy UK, trade body for solar panel installers, recommends that you check:

  • that your solar panels are producing electricity (check your generation meter or inverter)
  • for any damage, discolouration or strange smells
  • that you can’t see any loose parts on the roof (when you look from the ground)
  • that you know how to shut down your system in an emergency
  • for any visible damage to the roof, for example gutters, moss, birds’ nests (when you look from the ground)
  • if solar panels have cracked or moved out of place
  • for any signs of internal damage to your roof (when you look in your loft).

Many solar panels are covered by a warranty from the manufacturer. You may have additional guarantees from the company that installed the panels. If you notice a problem, these should be your first ports of call.

Use Which? Trusted Traders to find a solar panel installer near you.

Cold call 2: Do you need a solar panel voltage optimiser?

Voltage optimisers reduce the electricity voltage coming into your home. Some 16% in our survey had been approached about them. Some companies claim they can reduce your electricity consumption and cut your bills.

This is disputed. Before you buy one, weigh up the cost against potential savings.

Savings will be influenced by how high your incoming voltage is, how efficient your appliances are, how much electricity you use, and how long the optimiser is expected to last.

Use these tips from owners for how to make the most of your solar panels.

Cold call 3: Changing the inverter for your solar panels

Solar panel inverter

Cold callers had told 15% of solar panel owners in our survey that their inverter needed changing.

Inverters don’t tend to last as long as solar panels. So you’d expect to replace it during the 20+ year lifespan of your panels.

But you don’t need to replace your inverter if it’s still working. Newer models can be more efficient but they can also cost several thousand pounds.

Weigh up any expected savings with a new inverter against how long it will take those savings to pay back the cost of replacing the inverter. Also ask the company how it has calculated the expected savings.

Find out more: are solar panels worth it?

Cold call 4: Claiming your solar panel installer has stopped trading (when it hasn’t)

Some 10% said that a cold caller told them that the company that installed their solar panels had gone out of business, when this wasn’t true.

If you’re unsure, try contacting your solar panel installer. Check its website and try the contact information it left with you at installation. You can also search for installers registered with MCS on its website.

Ask the cold-calling company how it got your details. Don’t feel pressurised into signing anything with a new company before you’ve had time to digest all the information you need to make a decision.

Other solar panel cold calls

Solar panel cold caller on the doorstep

Less common claims that solar panel owners heard from cold callers included:

  • Their solar panels are a potential fire risk, 5%
  • They had been monitoring their solar panels, 4%
  • A fire switch replacement is needed because the law has changed, 2%

When we shared these with solar panel trade association Solar Energy UK, it warned that these could be dubious reasons that a cold-calling company may use to try to mis-sell to homeowners.

It’s very unlikely that a company would be able to monitor your solar panels remotely, nor tell without knowledge of your system whether it presents any safety risk.

If you’re concerned, contact your installer in the first instance or a recommended solar panel firm. If there is a problem with your system this will often be indicated by a fault code on the inverter.

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