New boiler advice

Rednan23

I have a really old inefficient traditional boiler with hot water tank etc that's on its last legs.

Few people in my street have changed to a combi boiler recently and i have a very reasonable quote from the company that did those for a new combi too.

I am not sure if it would be better to just replace with a new traditional boiler (including new tank etc).  We are in a 4 bed detached, 1 bathroom, 1 ensuite with 1 bath and 2 electric showers.  Its rare we use multiple outlets for hot water at same time. 

I think this all points to a combi being a good idea.  However I am a bjt nervous about my 3 young kids using hot taps/ leaving them on etc and wasting lots of gas.  Obviously would teach them but at least with traditional boiler you can control how much its used.  Probably over thinking this. 

Would appreciate anyone out there's advice/ experience on if switching to a combi is a good idea

Thanks
Carl

macman

If both showers are electric then you only have to worry about the bath and kitchen taps running simultaneously, so a combi may be suitable if your flow rate and gas supply is adequate. The RGI that quoted you should have checked this as part of the site survey.
A combi will involve more work, as the old tanks will need to be removed and the plumbing rejigged.
I don't quite get your point about wastage? If your kids leave hot taps running at present until all the hot water has been used then you are wasting a lot of money already.
You will get the much better economy of a condensing boiler whether you choose a combi or a conventional boiler: they all condense.

Rednan23

Thanks for quick and helpful reply.  The hot taps/wastage part is probably me way overthinking it.  It has only happened occasionally with our youngest if she has left the hot tap slightly on in the bathroom and it's a little while until we notice it.  I was worried with a combi that would fire up the boiler to be on constant maximum output until the tap is turned off? Where as today, worst that happens is you waste the hot water currently in the tank thats already been heated.

[Deleted User]

macman said:

You will get the much better economy of a condensing boiler whether you choose a combi or a conventional boiler: they all condense.

Not when heating hot water. The boiler will go to its installer set maximum flow temperature to reduce the time needed to heat the water.

Under Opentherm control, the protocol demands 93C when heating water. It expects the boiler to limit this to TMaxSet - sadly not all boilers do so.

macman

Nor will it run in condensing mode all the time when in CH mode. But, overall, the efficiency when compared to a 'really old' boiler than is presumably non-condensing, and possibly even has a pilot light as well, is going to be much better.

BUFF

Rednan23, how long do you expect to be in this house & how far down the line are you thinking?
The next replacement heating appliance (perhaps in 15 years?) is most likely to be a heat pump & then you will require a hot water tank. So, all the piping that you previously ripped out for a combi would have to be replaced  ....

Whatever you get, may I suggest that you upgrade your controls (Boiler Plus & the recent Part L changes will possibly mandate that anyway) & that the boiler is set up (flow & return temps)t to condense most/all of the time.

Running a shower from your gas-heated DHW currently will be cheaper & give you better performance than an electric shower.

 p.s. you may want to consider a self-closing tap if the issue with your daughter leaving it open persists

Reed_Richards

At some point in the past the hot water tank in my bungalow was removed and a combi oil boiler was installed.  The plumber made a terrible hash of the job so that hot water from the combi went to where the hot water cylinder had been, in the centre of the building, then back out to the taps. This made for a very long wait for hot water and at least a bucket full of hot water trapped in the pipes after a hot tap had been run.

Then I replaced the oil boiler with an ASHP and that needed a hot water cylinder again! 

northernstar007

i also had the same type of sys aprox35yrs old
changed to a worcester combi, you can set the hotwater temp on the boiler
love it very fast warm up