Replacement boiler

Clive_Woody

We currently have a conventional boiler, (Glow-worm 18hxi) that is just over 18 years old and starting to have a few issues and we are considering replacing it over the summer. Current issue we think is the thermostat has failed and keeps throwing up an error code (F5) and cutting off the boiler. The thermostat is being replaced later in the week.

We have an unvented cylinder in the loft which is around 8 years old and we would want to keep this. We have two bathrooms for four people who all like to shower daily so a reasonable water demand (kids will eventually both be off to university).

Couple of questions: if the boiler issue is resolved are we crazy getting rid of a functioning boiler, or would we simply be delaying the inevitable (I appreciate no one is a fortune teller)? With new boilers being a lot more efficient would we see decent savings that might in part justify this replacement?

After a bit of reading I am wondering if we would need a like-for-like conventional boiler or if a system boiler would be more appropriate? The pump is currently in the loft with the hot water tank.

Any thoughts very much appreciated.

grumpy_codger

Clive_Woody said:

...if the boiler issue is resolved are we crazy getting rid of a functioning boiler, or would we simply be delaying the inevitable (I appreciate no one is a fortune teller)? With new boilers being a lot more efficient would we see decent savings that might in part justify this replacement?

After a bit of reading I am wondering if we would need a like-for-like conventional boiler or if a system boiler would be more appropriate? The pump is currently in the loft with the hot water tank.

Any thoughts very much appreciated.

IMHO, you are. My boiler is at least 30 y.o., I never service it (there is no anything to 'service' there) and had minor repairs done twice.

A new boiler will need regular expensive servicing (at least because of the warranty) and will take years, if not decades, to pay back. Also, future of gas heating is unclear.

After a bit of reading I am wondering if we would need a like-for-like conventional boiler or if a system boiler would be more appropriate? The pump is currently in the loft with the hot water tank.

I'm no expert, but with a HW tank isn't your current boiler 'system'?

Clive_Woody

grumpy_codger said:

Clive_Woody said:

...if the boiler issue is resolved are we crazy getting rid of a functioning boiler, or would we simply be delaying the inevitable (I appreciate no one is a fortune teller)? With new boilers being a lot more efficient would we see decent savings that might in part justify this replacement?

After a bit of reading I am wondering if we would need a like-for-like conventional boiler or if a system boiler would be more appropriate? The pump is currently in the loft with the hot water tank.

Any thoughts very much appreciated.

IMHO, you are. My boiler is at least 30 y.o., I never service it (there is no anything to 'service' there) and had minor repairs done twice.

A new boiler will need regular expensive servicing (at least because of the warranty) and will take years, if not decades, to pay back. Also, future of gas heating is unclear.

After a bit of reading I am wondering if we would need a like-for-like conventional boiler or if a system boiler would be more appropriate? The pump is currently in the loft with the hot water tank.

I'm no expert, but with a HW tank isn't your current boiler 'system'?

The current boiler does not have a pump or a built in expansion vessel and was installed when we still had a cold water tank in the loft, so is a conventional boiler as opposed to a system boiler (based on my amateur understanding of the differences).

https://www.boilerguide.co.uk/boilers/types

FreeBear

Clive_Woody said: Couple of questions: if the boiler issue is resolved are we crazy getting rid of a functioning boiler, or would we simply be delaying the inevitable (I appreciate no one is a fortune teller)? With new boilers being a lot more efficient would we see decent savings that might in part justify this replacement?

I replaced a functioning Baxi back boiler back in 2023 - Doing the work over the summer months meant that there was no pressure to get it done quickly. I did contemplate a heat pump, but there were thermal upgrade requirements baked in to the Boiler Upgrade Scheme that would have pushed the budget beyond available cash reserves.

Whilst the new boiler is considerably more efficient than the old one (92%+ compared to 65% for the Baxi), I'm not saving huge amounts on gas - If I'm lucky, perhaps £50 a year. With your Glow Worm, it is around 86-88% efficient, so savings on gas is going to be minimal - If the replacement boiler is poorly set up, you may find you're using more gas (an issue if the flow temperature is set too high).

Now that the BUS rules have been relaxed (no need for thermal upgrades), I'd suggest looking at installing a heat pump. Octopus were quoting me around £2700 last year, which was a little more than I paid for a gas boiler. But the quote did include fitting larger radiators, so would have worked out cheaper overall (I'd already replaced most of the radiators & plumbing). I've heard of others getting quotes of under £1000, so worth looking at a heat pump.

ThisIsWeird

Clive_Woody said:

We currently have a conventional boiler, (Glow-worm 18hxi) that is just over 18 years old and starting to have a few issues and we are considering replacing it over the summer. Current issue we think is the thermostat has failed and keeps throwing up an error code (F5) and cutting off the boiler. The thermostat is being replaced later in the week.

We have an unvented cylinder in the loft which is around 8 years old and we would want to keep this. We have two bathrooms for four people who all like to shower daily so a reasonable water demand (kids will eventually both be off to university).

Couple of questions: if the boiler issue is resolved are we crazy getting rid of a functioning boiler, or would we simply be delaying the inevitable (I appreciate no one is a fortune teller)? With new boilers being a lot more efficient would we see decent savings that might in part justify this replacement?

After a bit of reading I am wondering if we would need a like-for-like conventional boiler or if a system boiler would be more appropriate? The pump is currently in the loft with the hot water tank.

Any thoughts very much appreciated.

Hi Clive.
The general consensus is, if your current boiler can be repaired fairly cheaply, and is otherwise working fine, then get it fixed and run it for as long as possible.
A couple of reasons - the first is that the cost of replacing it will be significant, and will overwhelm any small savings you may make from it's slightly improved efficiency. 
The second is, Heat Pumps and other technologies are constantly being improved, so the longer you wait for this, the more likely they'll be better, cheaper, and more efficient.
There will come a point when your boiler holds its hands up and says, 'enough - I'm done'. Until then, keep the baby.
Other things to consider for when that time comes; if you need to replace a radiator, then go 'large'. A larger rad will output the same as a smaller one with a lower water temp = efficiency savings with most systems. And, if you do go for another gas boiler, go 'system', and lose the wee F&E tank in the loft.

FreeBear

ThisIsWeird said: There will come a point when your boiler holds its hands up and says, 'enough - I'm done'. Until then, keep the baby.

But sods law says it will give up the ghost in the middle of winter and installers will have you by the short & curlies.

If the boiler is already having "issues", much better to plan a replacement during the summer without having to be rushed in to making (poor) choices.

ThisIsWeird

FreeBear said:

ThisIsWeird said: There will come a point when your boiler holds its hands up and says, 'enough - I'm done'. Until then, keep the baby.

But sods law says it will give up the ghost in the middle of winter and installers will have you by the short & curlies.

If the boiler is already having "issues", much better to plan a replacement during the summer without having to be rushed in to making (poor) choices.

Yes, it's obviously a gamble.