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John Laird John Laird is offline
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Default Pilot light gas usage

Dave Plowman (News) wrote:
In article . com,
wrote:
I've worked out that the pilot light on my old Vaillant combi boiler
uses the equivalent of 60UKP of gas per year, does this sound right?
This means a new boiler would repay in 10 years on the cost of pilot
light gas alone.


Forgetting the cost of the gas used for a minute, you're assuming all that
energy is wasted. It's not - only a proportion is. The rest goes to
keeping the water inside the boiler warm so it doesn't have to heat up so
far when it fires next. More wastage when the system isn't in use though I
suppose.


Of course if a boiler can effectively use this heat to keep the water
warm, you might also argue it is just as likely to be radiating it back
up the flue, once the balance has been reached between heat gain and
heat loss. At what water temperature this might occur, I wouldn't care
to guess. At 60 pounds/year and assuming the old boiler is
significantly less efficient anyway, an immediate investment in a new
boiler could be easily justified.

What surprises me is that a pilot light needs to be set at such a level
that it is producing 200W of heat anyway. Most of us would think that
leaving 200W of lighting on 24/7 would be wasteful in the extreme, even
if electricity is 3 times as expensive as gas.

[Slight topic shift - has anyone bought one of those power usage
devices and found it useful? I'm thinking of checking out what power
my various toys on standby use. For example, my laptop charger seems
to cool right off when off-charge (although I tend to disconnect it
anyway) whereas the brick for my DAB radio is always warm.]

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"Beware of programmers carrying screwdrivers."