How to buy solar panels Buying advice for solar PV

Solar panels on a roof

The cost of solar panels has been falling in recent years

In this guide you will find out how to buy solar panels, the sales tactics and scams used by dodgy companies, where you can get financial help buying solar panels, what to watch out for when buying and how to find a reputable installer.

How to buy solar panels

To highlight what you need to consider before having solar PV installed, we have produced a downloadable solar PV installation checklist

The checklist includes tips and advice on what you should do, and the questions to ask before, during and after a visit from a solar PV installer.

Which? investigation into solar PV sales

We've investigated how well firms assess properties during the initial sales visit. In 2011, we posed as a potential customer and invited 12 firms to a house rigged with secret cameras to see whether they were complying with the consumer code they signed up to. 

Identities have been disguised to protect our researchers.


Please enable JavaScript to access this content.

Make sure you don't miss any future Which? investigations - you can take out a trial to Which? for only a £1.

Solar PV sales tactics

We wanted to see if each surveyor from the 12 companies we filmed would assess the house properly and estimate payback time and profit from the Feed-in Tariff (FIT) accurately. 

We also wanted to see the quality of advice given and if all the important details, such as the need to replace the inverter within the 25-year period, were mentioned. Our key findings include:

  • Two companies breached code by offering a discount valid for 24 hours only and offering a 'first come, first served' discount in exchange for providing regular meter readings ('monitoring') – activities specifically banned in the code. 
  • One salesperson failed to mention ongoing costs, despite prompting, and another admitted he wasn't a surveyor - the consumer would have to make a decision based on a (likely inaccurate) quote made by a salesperson, before getting a professional evaluation from a surveyor.
  • Five did not go inside the loft to check suitability for installation of solar PV.
  • Five companies sent a salesperson, not a surveyor, but still gave a quote, estimate or price.
  • Seven didn't take into account the fact that part of the roof was in shade, so putting solar panels there was questionable.
  • Eight did not ask questions about energy usage or lifestyle.
  • Eight underestimated the time it would take for the system to pay for itself. We found that the methodology companies have to use under building regulations to estimate payback and savings is flawed and can lead to inaccurate predictions. While we are calling for this to be improved, it is worth taking these values with caution.
  • 10 failed to mention that the inverter (which is an essential part of a PV system and turns the current generated into useable AC current) would need replacing earlier, even when prompted about maintenance requirements and ongoing costs.

If you think you've been mis-sold solar panels, or simply want to know more about your rights, click mis-sold solar panels to find out how to complain. 

Finding a good solar company — things to look out for

Our investigations showed some salespeople using dodgy sales tactics and exaggerating the financial savings that could be made, so we strongly recommend that you do your own research first. Then compare the estimates of costs and savings you are given by salespeople against other sources of advice.

There are many solar panel installers out there, so we recommend that you always collect a range of quotes to compare. 

Visit Which? Local to find recommended solar panel installers, or search for a certified installer on the Microgeneration Certification website. 

Reporting dodgy solar companies

Companies that offer large on-the spot discounts or use other pressure-selling techniques deprive you of the chance to compare quotes and take time to think about its offer. 

You can report such firms to the Renewable Energy Consumer Code by calling 020 7981 0850, and to Which? on 01992 822800.

More on this...