On 24/08/2014 15:02, Broadback wrote:
On 24/08/2014 09:00, Richard wrote:

The main reason I don't have a Dyson vacuum cleaner is because he seems
to be a whiney git.
The idea is to reduce energy use, but how does work if the vacuum
cleaner has to be passed over the same area more often to pick up the
dust? The EU is also on planning to reduce the power of other domestic
devices, including kettles. Now if I wish to boil, say a litre of water
that, is at say 20 degrees C, surely it will take the same amount of
energy whether I do it with a low wattage or high wattage device. Or am
I missing something here?

Yes, you will use *more* energy doing the job with a lower power kettle
due to the increased losses through the skin of the kettle due to it
being hot longer.

I learnt this in Physics lessons in school by playing with an element
and a beaker. Turn the element down far enough, and the water would
never boil, even if you left it running all day. At other settings, it
used less power, but the increased time increased total energy usage.

What the EU rule is relying on is that people will get annoyed if vacuum
cleaning takes longer, so the makers will be forced by market forces to
increase the efficiency of their machinery.

--
Tciao for Now!

John.