Replacing old boiler for new to save money in the long run

Megaross

100% do it if you can afford it.

Conventional systems are rubbish compared to combi imo - naff pressure, wasteful, bulky and cost more to run. As soon as I've got the cash (it's about 4th on the list) going I'm binning mine and putting a decent combi in the loft.

Section62

Megaross said:

100% do it if you can afford it.

Conventional systems are rubbish compared to combi imo - naff pressure, wasteful, bulky and cost more to run. As soon as I've got the cash (it's about 4th on the list) going I'm binning mine and putting a decent combi in the loft.

In your opinion.... but that doesn't mean it is true, nor applies to other people/homes.

"Binning" a storage-based hot water system is going against what is reasonably predictable for the future - that however we heat our water, the most efficient/cheapest to run system in most cases will involve some degree of storage of energy when it is cheapest to buy.

Bendy_House

Any further Qs once 2 or 3 GasSafes have visited, then come back on here.

Listen carefully to what each says, and their reasoning. Equally, see how well they respond to your Qs.

Many GSs will have their own preferred brands (that's generally ok, especially if they are 'authorised' agents, so they should come with the max guarantee period - 10 years is not uncommon these days. Unless their chosen make is a dog.) and 'types'. For types of boiler, they should really be able to justify their suggestion*. If one pushes for a combi, for example, then they should have a bludy good reason for it. Not saying it isn't a valid choice - I have one - but, on the surface, it's not the most rational change here, I don't think.

For 'conventional' boilers (ie not combis), there are two basic types - Heat-Only and System. The former uses the wee F&E tank in the loft, and the other is sealed. Imo the latter is FAR superior, as there's less to go wrong (eg overflows from the loft), air is less likely to get drawn in, and corrosion less likely to occur in the rads and pipework. It has only one drawback that I'm aware of - it increases the pressure in the pipes and rads from around 0.2bar (what you currently have) to ~1 bar. That should just not be an issue, as rads etc are designed for up to 10 bar, and will cope with more, and the pressurised 'system' cannot go higher than 3 bar even in fault conditions. So, personally, I'd be insisting on a system boiler, but I know that some GSs are reluctant, and I don't know why - unless it's because a rad valve might begin to weep afterwards and require them to come back to pinch it up?

Anyhoo, see how you get on.

chrisw

I'm surprised everyone is pushing a nice shiny new boiler for 3 and a half grand.

I would take the opposite view that you are better off keeping your existing boiler until it becomes unviable to repair. That could easily be another 10, 15, 20 years off.

It might be worth having someone round to service it and getting a view on it's present condition. The suggested alterations to timings should have a noticeable effect on consumption.

Bendy_House

chrisw said:

I'm surprised everyone is pushing a nice shiny new boiler for 3 and a half grand.

I would take the opposite view that you are better off keeping your existing boiler until it becomes unviable to repair. That could easily be another 10, 15, 20 years off.

It might be worth having someone round to service it and getting a view on it's present condition. The suggested alterations to timings should have a noticeable effect on consumption.

Fair point, Chris.

I don't think anyone is pushing for a £3.5k replacement, tho' - I'd hope more like £2.5k max for a mini like-for-like. (I don't think it should cost more than that - ~£1k for the boiler and parts, ~£1k for labour - almost certainly one day.)

Yes, if an old inefficient boiler is nevertheless continuing to chug out heat, then a £2.5k outlay will take quite some time to recover! (Gulp - or possibly not these days...)

But, this beauty is seemingly throwing out ONE of its ~18kW in to the OP's garage! Never mind its normal, non-condensing, inefficiency - that's a doozie. (Well, a further 5% dooz). 

BUFF

chrisw said:

I'm surprised everyone is pushing a nice shiny new boiler for 3 and a half grand.

I would take the opposite view tha

my

t you are better off keeping your existing boiler until it becomes unviable to repair. That could easily be another 10, 15, 20 years off.

It might be worth having someone round to service it and getting a view on it's present condition. The suggested alterations to timings should have a noticeable effect on consumption.

In my very first post in this thread I laid out the 2 schools of thought. This has been further expounded on by various people & as the thread has developed & more information became available.

Only the OP knows their own needs/wants, their finances & housing plans for the future & therefore can make a (hopefully informed) decision that best suits them. 
Having said that & fwiw, if I were in the OP's position but with my needs/wants, financial position & future housing plans (no move planned for at least 10 years) I would go with a new system boiler+controls & an unvented cylinder (suitably chosen with an eye to use with a heat pump & possibly solar in the future).
The boiler+controls side should pay for itself with savings within their lives, if his current boiler were able to be kept running for 20 years it would actually have cost him.
The unvented is an upgrade (& gets rid of the pump) but shouldn't really affect running cost (unless current tank is not well insulated).

Bendy_House

Most cost-effective - new system boiler.

Best overall - also convert to unvented as BUFF says!

Golden_Holden

Thank you all so much for the input - the perfect blend of facts and expert opinion. 

A lot to consider!

dharm999

We changed our over 30 year old very inefficient Potterton Suprima 100 boiler and very small hot water tank recently to an upgraded system boiler, Worcester 35kv and 300 litre unvented hot water tank, that can be connected to solar panels in the future.  The hot water tank is a beast, and is now located next to the boiler, and so well insulated that we can't dry clothes anymore in the utility as the new boiler and tank give off very little heat, compared to the old boiler and tank.  We have good mains pressure, and we actually get decent water flow upstairs now, having previously had only a trickle from both hot and cold taps.  We upgraded the controls, to a Hive system, and now have a thermostat function that actually works!!

There was quite a lot of pipework to change, as the old hot water tanks were in a different room to the boiler, and he had to sort out the pipework in the loft where the old cold water tank was.

The whole lot, excluding the VAT was around £5.5k, not cheap, and probably slightly higher than we could have got elsewhere, but the plumber is someone we know, and trust, who will come out at a drop of a hat if there is a problem, and won't charge the earth.  So for us, it was worth paying a bit extra for the peace of mind.  

Since changing, we have reduced our gas usage significantly.  We now only have the hot water on, for an hour every other day, as we aren't heavy users of it, and so far, haven't had to switch on the heating.  I think once the heating goes on, we'll probably use half the gas we used to, due to a more efficient boiler, an insulated water tank and also having valves that actually work!!