We have reproduced part of an article by Cathy Debenham with kind permission from Yougen, an independent provider of information about renewable energy.

Free Solar panels : Is it too good to be true?

Solar PV panels worth £10-12,000, installed on your roof, free of charge - it sounds too good to be true, but is it really?

The 'rent a roof' model, as it is known, is proving attractive to installers and investors. A Shade Greener, Homesun and Isis Solar are just three of companies offering the service, and more will follow. So it's good for business. But is it a good deal for the consumer too?

First let's look at how it works. The company looks for homeowners with a south facing roof that is strong enough to install solar PV panels. They install a system free of charge, and agree to maintain it for 25 years. In return you sign a contract agreeing that they should receive the feed-in tariff income on all the electricity that installation generates for the full 25 years. An average household solar PV installation is around 2kWp. It generates an income of around £800 from the feed-in tariff which, under a rent a roof scheme, will be assigned to the installation company. You will just benefit from a reduced electricity bill as a result of using some of the free solar electricity generated. This saving may be up to £100 a year (on this size installation). However, how much you actually benefit will depend on how much electricity you use during the day when the sun is shining. If all members of the household are out at work or school all day, then you'll probably save less that that.

If you've got the capital to invest, and you want solar panels, it makes more sense to install the solar panels yourself and benefit from the feed-in tariff. Even if you have to take out a loan for the up front cost, Consumer Focus reckons it's a better financial deal than renting your roof.

So, if you don't have capital, and don't want to, or can't afford to, take out a loan, is it a good deal? On the face of it, it could save up to £2,500 in electricity bills over 25 years (at today's prices - although it's likely to be more as energy prices rise). But I'd want to know more about all sorts of things before I went ahead. If you want to see the list of questions to ask the "rent a roof" companies, then go to the full article.