27 Nov 2019
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United Kingdom

We've just moved into a 4 bed / 1 bath detached house. The combi boiler is around 8 years old, it's working but when our friend who is a gas engineer serviced it recently he believes there is a problem with the heat exchanger.

We're looking to extend the house in the near future, extending over the garage to give us two further rooms upstairs so we'll end up with 2 to 3 bathrooms.

We expected to have to change the boiler during the building work but might have to swap it out sooner now given the problem with the heat exchanger and the cost to repair it compared to buying new and getting a decent warranty.

Our friend has suggested we could install another combi but also add a cold water tank in the loft to feed the showers / baths. He believes this would provide us with enough water to run two showers / taps etc. at the same time without noticing a drop in pressure and be future proof given the building work we intend to do in the next 2 - 3 years.

I'm posting this in the hope of getting more opinions on what our options are and what might be the best solution. Costs isn't the main focus, more that we don't want to install something now and then find us replacing it again in a few years time.

Thanks in advance!

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Hi Ben.

If you go on most brand boiler websites they have a tool to determine the best size boiler and tank etc for you house needs. If you check out baxi and ideal they have this. Pop in your bedrooms shower and bath needs. Combis aren't any good for large hot water needs. System boiler with a unvented cylinder maybe a good option. Lots of advice online about which best for you.
Thanks for your reply Martin. I had a look at Ideal’s website and it asks you to select between Combi, System, and Heat Only boilers before listing the options. I assume this means you could achieve the end result with all three but still unsure what would be the best option. Should I rule a combi out because we’ll have multiple bathrooms? But on the other hand it’s great to have hot water on demand for the washing up etc!
Combi great for instant water but people say not so good for running a bath or multiple taps running.Try all three types in the selector. My Baxi is 30 year old heat only boiler. ( serviced every year and not cost me a penny for repairs )Yes people say ooh get a combi etc but its also the controls you use as well that count. My heating is set to on all the time and the room stat is programmed for different temps thru the day to match when we get up and go to bed. We more of a shower family so the hot water is set for washing/ washing up at breakfast and tea etc. Going to replace it now thats why i know about the Ideal and Baxi planners. Still going for heat only or system boiler. Some of the thermal stores and hot water cylinders now are very eco and cash friendly after the initial payout of course. Worcester Bosch a good brand to i believe. Watch out for the guarantees and read the t & c as it may say 10 years but it has to be installed by an approved Brand installer/ yearly service/ magna filter etc.
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I'm a firm believer in asking a reputable, recommended boiler installer in to take a look, perform a quick survey and give recommendations. Get as many chaps in that you can to give you estimates. Using a specific manufacturers website for any thing other that technical specs will ovbiously lean towards their own products whether directly or subversively. That and they can't take into consideration real life requirements.

I would never recommend WB as I believe that their boilers are over priced for what they are and don't have a very good track record these days. They used to be the boiler of choice before they started to use plastics internally.
as @Madrab says ,get some quotes and watch to see what tests they do on your water supply as in pressure and flow rates, if it is suitable then an unvented cylinder would be your best bet, you can heat this with a syste or heat only boiler or a combi, and use the combi HW side to either heat say the kitchen or utility room or whatever,as for putting a cold water storage tank in the loft ??I think you have mis understood , that would be a complete waste of time and money
It is also possible to install acombi to feed local taps, and also plumb the heating circuit into a Y or S plan, or any combination of zones, one of which could be a cylinder, located nearer to the furthest taps.

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