[OpenTRV-interest] Boiler replacement economics (Was: Weather compensation)

[John]

On 23/12/16 08:03, Simon Hobson wrote:
> John <john at stumbles.org.uk> wrote:
>
>> But they say they estimate that replacing standard- with
>> high-efficiency boilers from 2005 onwards (for a change from SEDBUK
>> c.80% to c.90%) resulted in average savings of around £95 a year
>> ...
>
> And one has to wonder, how many people were persuaded to replace a
> perfectly functional boiler with a new one because "it'll save you
> money". On the basis of those figures, I'd say that replacing a
> boiler that doesn't need replacing for some other reason will never
> reach a payback point (even ignoring the cost of finance etc) - if a
> replacement costs (say) £2k* and will save £100/yr, then that means
> it'll take 20 years to repay through reduced gas bills.

Quite: something I consistently pointed out to clients, along with the 
mendacity of the official line. And I note similar post-factuality in 
the spiel in the consultation which claims that the price of 
high-efficiency boilers fell after the change of building regs in 2005 
which mandated them, which it did not do significantly. (In an inspired 
piece of spin doctoring they also assert that the price of HE boilers 
was less than SE ones a few years later, which is probably true because 
SE models were by then such a niche market their price had probably 
risen hugely!)


> I've lived with 20 year old "old" boilers in the past, I have zero
> expectation of any "modern" boiler lasting that long - especially a
> combi with all the extra gubbins to break (or just leak onto the
> electrics). So the replacement would be needing replacing before it
> had paid for itself.

*BZZZT! - Fallacy Alert!*
https://en.wikipedia.org/wiki/Survivorship_bias
You need to compare the boilers being installed today with *all* the 
boilers that were being installed 20 years ago, not just the ones that 
are still running.

Also you should compare modern combis with 20 year old combis, not with 
heating-only boilers.


-- 
John Stumbles                                    http://stumbles.org.uk
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