Dave Plowman (News) through a haze of senile flatulence wrote:

> In article ,
>    Pete C  wrote:

> > >Out of curiosity I calculated how much gas my boiler pilot light
> > >consumed and took a meter reading at 9pm and again at exactly 9pm the
> > >next day. The heating & water have been off all that time with just the
> > >boiler pilot light lit.  I included the 2 red decimal numbers in the
> > >meter readings and in 24hrs it had used 0.18 unit, which over a year is
> > >65.70 units.  If my sums are correct (Calorific Value of 39.4) I work
> > >that out to be around 2081kWh.  Is that amount of consumption about
> > >right for a pilot light? On 2p per kwh that would be around 41 a year.
> > >The boiler is a Potterton Prima B about 6 years old.
>
> > Over 15 years that could pay for a condensing boiler....

Yep.

> But the calculation is flawed by making it at this time of the year with
> the boiler not in use. For the 6 months or so of the year when the heating
> is needed - or it's used for just heating hot water - all that energy
> won't be wasted. There's probably a diversity calculation that takes this
> into account.


8760 hours in a year.  A boiler is firing for about 10% of that time, if
that.  So, 90% of the time the pilot is not needed and a waste heating the
outside, and adds nothing.  So, 37 per year for 10 years is 370, probably
a lot more as gas goes up in price.  Which more than pays for a condensing
boiler.  Anyway you have to fit condensers anyway.