How do I calculate annual cost savings for replacement combi

[Glow-worm]

Hi

I would like to work out the cost savings if I swapped our old combi boiler for a new one.

The existing combi is a Glow-worm Swiftflow 80, Efficieny Band F (10-15 years old?).

I am looking at a Glow-Worm Betacom 28A HE Gas Combi (http://www.boilers2go.co.uk/Glow-Worm-Betacom-28A-HE-Gas-Combination-Boiler.html).

We only have a 2-bed mid terrace and I think this is powerful enough.

HW is currently coming out at 9 LPM in to a weir cup and that is fine for us.

Also Energy Saving trust website says 9KW is what we need for boiler output as its a very small house.

However I can't find any info on running cost savings, only that newer boilers are more efficient!

Thanks peeps.

You might find our boiler calculator useful - it's accessible on www.glow-wormheating.co.uk

Using a high efficiency condensing boiler with heating controls could save around £200 a year.

For more information and advice on cost savings:

http://glow-wormheating.com/save-gas/reduce-energy-bills/green-savings-calc.php

Hope this helps.

 

[cypdhawr]

This threads a bit old but I came across it when searching for 'boiler savings calculator' so someone else might. This has helped me decide as moving from a bungalow with an old boiler condenser: boiler savings calculator .It shows savings made by going to an a-rated boiler. Pretty much backs up whats said in the thread but gives you a £saving visually. Not entirely sure how accurate mind

 

[Dan Robinson]

Looks like utter Boolox to me.

 

[cypdhawr]

Haha ok. It not a good demo of whats been said? Thought it might help certainly helped me. Or so i was thinking. Do you mind explaining?

 

[Dan Robinson]

It thinks it will save me £2200 a year.

I have an A rated boiler with class 8 erp controls.

Last time I saw crap figures like that, it was on Helplink's website.

 

[Dan Robinson]

It took no account of my hot water usage, storage patterns or boiler control.

 

[Dan Robinson]

certainly helped me.

Probably not....

 

[bernardgreen]

An A rated condensing boiler will only be that efficient when it is condensing. Many condensing boilers are not able to operate at their claimed efficiency because they are operating in non condensing mode. This is due to the boiler being installed into a system of existing radiators which is not desgned for a condensing boiler. The water returning to the boiler from the radiators is too hot for the boiler to condense water vapour.

The requirement is that a new boiler must be a highly efficient boiler, there is no matching requirement that the radiators must be altered to ensure the boiler can operate as a condensing boiler.

 

[Dan Robinson]

Luckily most radiators are oversized and thanks able time condensing boiler (when at up properly) to condense. Set up properly properly and 100% of the heat exchanger is in condensing range rather than the last bit.

 

[bernardgreen]

Many condensing boilers are not able to operate at their claimed efficiency

Luckily most radiators are oversized

Do you have any statistics from independent research on

{1} the percentage of condensing boilers that are retro fitted into systems with oversized radiators and thus can fully condense

{2} the percentage of systems that have retro fitted boilers that do condense but only by reducing the flow temperature to a level that does not provide adequate heating.

( reducing flow temperature results in the return temperature being low enough to enable the boiler to condense )

{3} the efficiency of boilers designed to operate as condensing boilers but operating for most of their time as non condensing boilers.

( in domestic boilers the design constraints imposed on a condensing heat exchanger may result in that exchanger being less efficient than a non condensing heat exchanger if the return temperature does not allow the condensing heat exhanger to condense. That is according to results from an informal university research project )

 

[Dan Robinson]

Bernard, I look after the better part of 3000 customers. Some with as many as 5 different Heating systems in a single property.

These range from single room bedsits to £10,000,000+ luxury homes, with the odd factory and stately home thrown in for good measure. I think my own database and personal knowledge provides enough evidence as I'm sure the rest of the professionals here will add too. Some with more experience and clientele.

 

[Dan Robinson]

Perhaps you should cite some of the waffle in your last post?

 

[halfway]

Most upgrades from standard to HE boilers take place after or in conjunction with insulation upgrades. New windows, extra attic insulation, etc.. That results in the existing radiators being in effect oversized and allows for lower operating temperatures.

HE boilers, even when run in non condensing mode, run at about 8% higher efficiency than standard ones.

New installs also require power flushing and that would also help they system. Often open systems are sealed during a new installs and this can also be of benefit in the long run.

Sorry that I don't have links to research, but it is stuff that I have learned over the years and at the time felt no need to keep reference material.


Dublin

 

[Dan Robinson]

Been racking my brains all evening (well not really) fir a solitary radiator that's needed upgrading since 2005 as a result of fitting a condensing boiler.

Bearing in mind I often use hot water priority and dual setpoints.

Came up with a grand total of zero.

How many boilers have you installed in that time Bernard? How many do you maintain? How many systems have you set up?

 

[bernardgreen]

Most upgrades from standard to HE boilers take place after or in conjunction with insulation upgrades. New windows, extra attic insulation, etc.. That results in the existing radiators being in effect oversized and allows for lower operating temperatures.

So the new boiler is not the sole reason that feul costs are reduced.

How many boilers have you installed in that time Bernard? How many do you maintain? How many systems have you set up?

Since 2005 ? , no installs ( a trusted RGI installed the boiler of my choice in this cottage )

Maintain on a contract fee basis, none

Systems set up. the one in this cottage. have balanced at least two.

You didn't include the question :- " How many systems have you seen that needed improvement ? "

Among friends, ex-colleagues and relatives at least six systems that I recall where a condensing boiler was installed and then did not worked as the installer claimed it would. Bottom line the house / flat was not as warm as before. One where the new combi was removed in less than a year and tanks and cylinder were re-installed.

The bottom line is that there are some installers who do not take fully into account what the house / flat owner needs and simply stick a boiler on the wall in a way that gives them best profit.