My fairly ancient Potterton Prima was serviced today by a Bord Gais (Gas Board) technician.
He said the boiler was about 13 years old, but was in pretty good nick. I asked if modern boilers were better, and he claimed that a modern boiler might be 90% efficient, while the Potterton would be about 60% efficient.
Is that true? Are modern boilers much more efficient?
Absolutely. I wouldn't know about the precise % numbers quoted, but doesn't sound unreasonable. It's because modern boilers are fundamentally different - in the UK at least they *must* have condensers, which extract much more energy from the gas than old models like yours.
See
Those would be published figures based on a method of measurement used in the UK and in in a database known as SEDBUK. This is based on seasonal weighting for UK weather conditions and Dublin would be near enough to that.
Some of the older boilers were certainly in the sub 60% range while condensing models of recent design are all in the 90-91% range.
The message from Timothy Murphy contains these words:
Well he would, wouldn't he.
No and yes. Condensing boilers might make 90% or even a bit more. Modern non condensing boilers will be something more than 10% less. IIRC the Prima should be 75% efficient so it wouldn't make sense to replace it with a non condensing boiler only 5% better, at least until the Prima expires.
A projected possible saving of 30% does not necessarily offset the cost of a new boiler plus installation. Just look at the number of condensing / combi boiler problems that crop up on newsgroups. 30% of your heating part of your gas bill may take some time to pay off a new boiler setup and by then it will be obsolete before it actually starts to save you any money. :-)
Gio
Probably. The modern condenser will certainly be in the 90%+ range. Your Potterton may be down in the 60% or below bracket. You can look it up in the SEDBUK database.
Yup, for an idea of why, see here:
Our old 25 year old boiler which we had replaced was about 50% efficient, so moving up to a condensing boiler at just over 90% efficiency was a quite a leap.
Replacing an old boiler doesn't just come down to economics, a small factor that also comes into play is how polluting is it. A lot of people simply don't care, especially the older generation. That's up to them, but I do, in the same way that I don't leave litter laying around outdoors I don't want to unnecessarily cough up my polluting fumes into the atmosphere.
I remember one heating engineer that was servicing the old boiler saying that I probably wouldn't consider driving around in a car of the same age. Which was a fair point.
While this is true, it is not an easy call when you work out the full environmental cost of disposing of a boiler and replacing it with a new manufactured product; at 25 years old you have probably had the lions share of use out of the first boiler, so ripping and replacing may well result in a lower environmental cost. Much will depend on what happens to the old one once it has left your sight.
The message from Roger contains these words:
Just been wrestling with the Sedbuk database.
As it is now in the hands of defra I am surprised it works at all. As it is you can't search for Potterton as a manufacturer, the search display has the flue fan information reversed and of course there is no Prima model listed. However as I have one of these myself I know that it is a Profile Prima. The maufacturer is Potterton Myson which is one of the search terms but the models are invisable as they are listed as Potterton. Anyway enough of the whingeing.
Potterton Profile manufactured between 1988 and 2001.
50e - 75.4% 60e - 75.1% 80e - 74.4% 100e - 73.9% 40e - 71.8%All very much of a muchness except for the 40e. Odd that, particularly as the rest decline with output.
Yes, it's an interesting argument but i'd like to see the environmental figures for disposal.
Condensing and combi boilers are not the same thing. System boilers can be condensing. Many of these problems are due to cheap boilers - quality boilers have few faults, as with any type of product. High quality condensing and combi boilers produce few problems.
Obsolete or not, it still works and it saves on what you had before.
"Timothy Murphy" wrote
AIUI some of the boiler's "efficiency" saving is the reduced output of heat from the boiler itself. If you rely on this for heating the room in which the boiler is located, then fitting a boiler that does not generate local heat cannot be counted as improved efficiency IYSWIM (except in the "so-called" summer months of course).
Phil
Simple. Measure the box and weigh it. It's that amount of landfill use.
Wot about the toxic stuff inside the electronics (I suppose even old boilers have some?) And I think more significantly than disposal of the old boiler, surely, it's the environmental impact of producing a new boiler which needs to be weighed up against the energy saved by swapping it in.
David
Tell me about it - in my SuperHeat program there is a procedure called 'MassageMake' which takes the database-derived name and tries to straighten it out. My other big gripe is that at the end of 2005 they removed the minimum output field, so you now cannot tell (without going back to the mfrs info) whether an 18kW boiler is 18kW or 6-18kW modulated, which is why I stopped promoting our free QSEDBUK program.
Thanks very much for that useful info. So I guess a new boiler would save around 17% (going to N/.9 = 1.11N from N/.75 = 1.33N).
The price of gas was hiked enormously here in the last year - I think it doubled, and then there was a small reduction (an election was coming up ...). I guess the increase is probably due to Mr Putin.
I wouldn't have thought it would be too expensive to change boilers? [Nb I am NOT thinking of d-i-y!)
The more gas you use the quicker the payback.
Those figures are for a new boiler serviced and tuned properly. An old boiler will be less efficient than those figures.
Do they all go to landfill? Surely they can be recycled.
My old boiler didn't have any PCB's or anything. Although I would imagine it must have had some sort of rudimentary electrics to get the programmer to start it.
I think that this is an argument between utopia and practicality.
Really, the only way to address this would be to put a requirement on manufacturers to dispose of the products they sell at the end of life. They may choose to do that themselves or to outsource to specialist firms.
However, the reality is disposal in skips much of the time, I suspect.
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