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The scam of rooftop windpower generation

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Posted by Eeyore on December 8, 2006, 11:09 pm

I was pleased to discover the link below on a *repectable* home windpower site
about the curent scam in the UK promoting rooftop windpower generation no doubt
targeted at well-meaning townies who'd like to see themselves as 'green'.

For my own part, I'd been amazed to see that one of the most prominent
manufacturers of this kit ( now being sold in a well-known DIY chain ) shows
average windspeed figures at 25 metre elevation to promote their product despite
saying they can't install it any higher than your roof !


"  Rooftop wind turbines are a load of nonsense
Anyone who has experience in the industry knows that wind turbines require
substantial quantities of wind to produce power.  There may be strong gusts and
turbulence around buildings but only a small amount of power  is available in
such locations.

There are a number of manufacturers of rooftop wind turbines.  They have sprung
up to meet popular demand.  There is no evidence that their products can deliver
what they claim.  Here are some of the web sites.

The manufacturers of rooftop wind turbines invariably make quite unrealistic
claims, and present a very strong marketing rather than engineering


Posted by Rolf Martens on December 9, 2006, 9:52 am

rabbitsfriendsandrelations@hotmail.com says...



No doubt you're right. The entire windmill propaganda is for
reactionary political reasons, in order to make some people
think there's something wrong with the really efficient energy
sources - nuclear power plants, above all, and also oil etc.

Rolf M.

Posted by danny on December 9, 2006, 1:25 pm

Yep a scam just like chasing the wind for the cash you have spent.
There is only one type that may pay and that is the Helical which generates
when the wind comes in all direction up down sideways.
Suburbs are useless for wind generation, only
Heat pumps are sound in town.
People contemplating spending the 1600 would be better off put in extra
insulation, upto 12 inchs is good.

Posted by Eeyore on December 9, 2006, 7:08 pm

danny wrote:

Absolutely spot on and it wouldn't cost 1600 either.


Posted by Ian Stirling on December 9, 2006, 11:48 pm

Upgrading loft insulation is probably of rather debatable payback, if
it's got a few inches already.

Going from 6-12" halves the U value from 0.26 to 0.13.
For a 100m^2 roof, and a 10C average difference, that's a saving of
130W. (neglecting labour to put it in, assuming it's possible).

Assuming gas at current prices, that's a payback of over 10 years.

In many cases, there are better investments you can make - for example,
in my case, a new fridge/freezer unit would pay back in 5.

I'm actually at the moment adding 100mm of rockwool to my walls, as
they were uninsulated. This is a large job, and will pay back in some
2-3 years.
200mm would make the rooms even smaller, and better performing
insulation would mean it wouldn't get done at all, as it won't pay back
within a reasonable period.
(quality foam insulation 10cm thick would have tripled the cost.)

First you start with a spreadsheet, and calculate the amount of heat
going out of your walls/ceiling/floor/windows/gaps.

Then work out cost/benefit for all of these.

Single glazed windows - for example, unless the rest of the property is
well insulated are rarely a major source of heat loss.
And double glazing is comparatively expensive, compared to some other

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