A worrying report came out this week about the financial unfeasibility of solar power. The Royal Institute of Chartered Surveyors’ (RICS) Building Cost Information Service has done the maths, and while installing solar panels on your roof will cost you somewhere in the region of £4,000 – £5000, it will save you about £24 a year. Even with rocketing fuel prices. That’s pretty lame.

And how many times does 24 go into 5,000? 208 and a bit, which is how many years it would take you to recoup the investment.

Compare that to cavity wall insulation, which costs about £440 to install in a terrace and could pay for itself within three years by saving £145 a year in heating bills. Can you see which option is most cost-effective?

Even a new boiler – average cost £1,720 – will save you £95 a year and so repay itself in less than two decades.

So if you’re installing solar panels to save money, then don’t. None of us will see a return in either our lifetimes or those of our kids.

And yet despite this I’d happily pay a little more for a house with panels installed. Somehow when it’s part of a mortgage and not coming straight out of your own pocket it feels a little easier to swallow.

But that’s rather missing the point, isn’t it. For true self-sufficiency, installing green technologies like solar panels and wind turbines is more about ensuring a constant, reliable supply, breezes and clouds permitting, so even at that cost, and with such a small return, it still makes sense. So long as you install whatever other devices you can to cut down on energy leaks.

The RICS guide costs £17.99 (no word on how long it’ll take to recoup that cost). More info here.

This is a bit of a blow coming on the back of the British Wind Energy Association’s report revealing that it could take 15 years of generating green electricity to offset the environmental impact of constructing a home wind turbine in the first place, never mind the financial cost of buying and installing it. Donnachadh McCarthy installed a turbine in 2005 at a cost of £2,400. This year had been its most successful to date, generating a grand total of £2-worth of electricity. If it was ever able to keep up that kind of output, it would take him 1,200 years to get his money back.

Personally I’m still holding out for Ben Storan’s cheap, lightweight wind turbine, which would make a great addition to one of my spare chimneys.

Photo by Clownfish on Flickr

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