choosing boiler

Jan 07, 2004 34 Replies

But the majority of the waste is going out the flue in the gushing flow of

2-300C waste gases, replaced by an equal flow of freezing cold outside air being drawn through into the house due to the open flue not providing a dedicated air supply. That is the main difference.

I don't know if the SEDBUK calculation allows for case losses as being a useful gain, anyway.

Christian.

So is your name really Cherie?

I can't think of anybody else who would say that, and from what I've heard, even she has a marginal view on that.......

.andy

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Don't forget that most of the loss from the boiler is what is going out of the flue......

From the SEDBUK list, there have been several generations of Kingfishers, but the older ones are going to be around 65% efficient, possibly even less.

I changed from a 65% efficient Glow Worm to a 91% condensor and achieve between 25 and 30% better fuel economy - pretty much in line with what SEDBUK say.

As far as the bathroom is concerned, you might need to add in a radiator, perhaps in the airing cupboard, to release the equivalent heat in the room.

.andy

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You have take into account that this fellow hasn't serviced his boiler for

20 years. He boasted about the fact. So he would save a ton of money on installing condenser and with the money he saves he can go out and buy many pairs of yellow DeWalt boots...and the odd bright yellow cap too. Look just the part in the ale house leaning on the bar.

Sorry, but virtually no one takes any notice of the boiler when they buy a house. Providing it works and isn't identified as just about to die, then what colour it's been painted would be a more significant factor than if it's condensing or not.

I have seen one report that a surveyor actually warned that a condensing boiler had a significantly higher maintenance cost, so in this case it was regarded as a negative factor.

You didn't get the point. When it's mandatory and only condensers are available people will know this, and they can readily identify a condenser by the plume. It should go the same way as DG in customer awareness. Financially DG is not worth it for the energy it saves. A super long payback, yet people like the idea of sealed windows and are prepared to pay for it.

No accounting for a d*****ad surveyor. I never met a surveyor who anything about CH, DHW or gas in any sort of detail to pass any relevant comment. It is not their field. They are good at concrete.

like to

With approx 20 million gas heated homes in the UK that makes the average boiler life in the current housing stock about 15 years which accords with my experience. The ones which are shorter lived than this average IME would tend to be the low end combis.

Err, it's a balanced flue.

Thanks for that Andy but it's still 250-300 more than a non-condenser, and the budget is tighter than a ducks behind. Neil

OK, well given that, the equation becomes projected reliability and maintenance costs in the context of how long you intend to keep the property. If it's going to be a shortish period then you might as well save the maximum on the capital outlay.

.andy

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However, this is not a guide to lifetime of current boilers, it's a guide to lifetime of boilers fitted some 10 or more years ago, and as such I think it's a reasonable figure.

If, say, condensing boilers happen to have a lifetime of only 5 years, then this will not yet have had any noticable effect on these figures.

Combi's account for approx 65% of all boilers fitted. Many boiler are being ripped out for power shower performance and space saving, rather than the existing boiler being defective.

The whole nation is property developing, haven't you seen TV?

Not if you buy a Baxi Barcelona

I accept your argument is true in prinicple. IMHO I don't think that the current replacement units are significantly different from what has gone before. True there are more crap combis to bring the average down but then there are also less open systems with dire pumping over or air entrainment.

The low tech boilers from the 70's are still going strong assuming there is no pumping over etc. However they tend to lose favour with their owners when there is a fault.

Even so, the waste gases are much hotter than with a condensing type. This is the major energy efficiency difference. If the boiler actually condenses internally, it is even better, because as well as the temperature difference, you get the latent heat of condensation added to the equation.

Christian.

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