Economy of 10 year old combi over new condensing boiler

In other words is it economically viable to replace my combi?

Reply to
Broadback
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Look up your old one and prospective new one(s) up on SEBUK:

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Unless the efficiency difference is > 20% it's probably not worth it:

£2000 for new boiler and install, 10 year life = £200/year. £1000/year gas bill, required saving of £200/year = 20% reduction. £1000 for new boiler and install, 10 year life = £100/year. £500/year gas bill, required saving of £100/year = 20% reduction.

I doubt a 10 year old combi has an effciency less than 80%, our great lump of cast iron oil boiler manages over 80%...

Reply to
Dave Liquorice

Many thanks Dave for your comprehensive answer.

Reply to
Broadback

Additionally, your old boiler has little to go wrong, and most of the faults can be simply sorted. A new one is an order of magnitude more complex, and you will end up having to call in assistance.

If you actually pay for the annual service that is strongly recommended, that is another chunk out of the savings.

Chris

Reply to
Chris J Dixon

Look up your old one and prospective new one(s) up on SEBUK:

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Unless the efficiency difference is > 20% it's probably not worth it:

2000 for new boiler and install, 10 year life = 200/year. 1000/year gas bill, required saving of 200/year = 20% reduction. 1000 for new boiler and install, 10 year life = 100/year. 500/year gas bill, required saving of 100/year = 20% reduction.

You are assuming the price of gas will not continue to rise.

Reply to
harryagain

ear.

reduction.

ear.

reduction.

If it does, then you can switch to the new more efficient boiler then. Given that boilers have finite lifetimes, switching too early has a cost.

Reply to
Martin Bonner

Much depends...

First check what the efficiency of the the model you have is... that will let you work out the difference in running costs.

Consider if there are other factors at play - for example an existing boiler that is frequently going wrong, or likely to need replacement in the near future anyway, alters the decision somewhat.

The sum changes again if you are happy to do all (or most) of the work yourself - since that brings the price of a decent quality boiler down to around £1k.

Factor if you need to borrow money to do it. If the money is currently "savings" then given the return on most deposit accounts get these days, even a 10% reduction in gas bill may represent a much better return on your money than the less than inflation return the money is getting as it is.

Alternatively you may well find there are lower hanging fruit to be had elsewhere - say with with extra insulation - a 50% reduction in heat loss beats a 20% increase in boiler efficiency.

Reply to
John Rumm

£1000 for new boiler and install. 10 year life. £500/year gas bill with new boiler 15% more efficient than old which produces a £575/year gas bill. 7% compounded gas price rise over ten years gives new boiler £6908.22 total gas bill, old £7944.46 difference £1036.23, so a whooping great profit of £36.23 ...

Getting a 15% efficiency improvement implies that the current one is around 75%, which for a 10 year old combi I find unlikely. Knock the efficiency improvement down to 10%, retain the 7% compounded price rise and you are £309.18 short of the £1000 capital cost. At a 10% efficiency improvement for the savings to pay for the new boiler inflation of gas price has to be 15% compounded every year.

Reply to
Dave Liquorice

Hmmn..., I wonder where I fit in here. I have a normal (old style with lagged tank) boiler. Not had it serviced in the 12 years since I moved in.

That's got to be a grand in service cost savings.

Reply to
Road_Hog

If you are planning on selling your house and want to improve your Energy Efficiency Report, you can probably buy a new logo from Ebay to stick over the old boiler model number.

Owain

Reply to
spuorgelgoog

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