Combi vs Conventional Boiler

28
Found 28th May 2015
I have a 25 year old conventional boiler, It did its job all right, but now it needs to be replaced in a 3 bedroom house, with just one bathroom. Most of the plumber are suggesting to go for combi, as it is most efficient and its free up space in loft plus in the cupboard.

But My heart says conventional is better as it breakdown less, but when I think about the hotwater cylinder , expansion tanks , god know how long they will last. They are already over 25 years old.

Really not sure which one to go for - combi or conventional???

Please help! And share your experience with Combi! Are they long lasing.! Or its just plumbers who want your boiler to be replaced in every 5 to 7 years!

Many thanks for all your comments. I did bit more search over the internet and my conclusion is that Combi is cheaper to run, takes less space but will only last maybe max 10 years if you're lucky (otherwise typically 7 years). Conventional can last forever at the cost of higher gas bills. However, I am planning to go with Combi with Vissemann and as soon as it is installed take the Boiler breakdown cover. full peace of mind.

Few good forums in MSE.

forums.moneysavingexpert.com/sho…219

forums.moneysavingexpert.com/sho…635

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28 Comments

I am not a plumber, however, any combi or conventional you buy will be new and not probably built as they were before. Combi-condensing boilers or condensing boiler is more efficient energy wise according to my plumbers. Get 3 quotes from reputable plumbers and ask lots of questions in a general chit chat. ie which boilers go wrong more often, which are easy and cheaper to fix etc. From 3 or 4 plumbers you should along with internet info on boilers you should have a v. good idea of a good brand and cost.

I hope this helps and let us knowhow you get on.

How many bathrooms / showers ?

You could stay conventional but have a sealed system. This would allow you to loose the expansion tank, but keep the hot water cylinder. Also have you checked the water pressure ? I live in a low pressure area, and out of 4 plumbers that quoted me on a new boiler, only one checked the water pressure ! Conclusion was although a combi would work, if the pressure dropped a bit in the summer, I potentially could loose my hot water, so ended up staying with a conventional boiler which I'm more than happy with.

Combi for me.

get a one that has a bigger than needed output for you house then its not straining to do its job that's what I was advised

I have a condenser boiler and it's very efficient

rearden4444

But My heart says conventional is better as it breakdown less



Does it? Why do you say/think this?

Banned

Just changed from a old open vented system and I agree they are very reliable.

plus with combi Is you get airing cupboard space and it seems to heat rads up very fast. my old boiler was 11kw and this combi is 24kw. I can tell the difference.

pick a combi with a decent warranty. We got a baxi duo technology with magnaclean filter 7 year warranty fitted for 1900.

Original Poster

thats because I read lots of negative feedback on various top class combi boiler at reviewcenter.com.

Personally I would recommend a combi for your requirements. We had a Veismann combi installed a few years ago. It has a large built in storage tank for hot water because have a 5 bedroom house with 2 bathrooms.

Have a look at Veismann they are German made and have an excellent reputation.

Original Poster

for baxi compact combi one plumber quoted 2.8k and for worcester combi another plumber quoted 2.6k. Both have got pretty bad reviews in terms of breakdown at reviewcenter.. kom.

for conventional type its just 500 quid cheaper.

Original Poster

yes I read viesmann combi has slight better review than baxi and Worcester bosh.

Banned

people only write a review when they have a breakdown. same with cars.

Banned

rearden4444

for baxi compact combi one plumber quoted 2.8k and for worcester combi … for baxi compact combi one plumber quoted 2.8k and for worcester combi another plumber quoted 2.6k. Both have got pretty bad reviews in terms of breakdown at reviewcenter.. kom. for conventional type its just 500 quid cheaper.



those prices are way too high.

I am a plumber, i would recommend a good quality combi like vaillant also i would also recommend a Worcester boiler but these tend to be more complicated to fix if they do go wrong. You can not beat conventional for reliability as its all separate and less parts to go wrong. You can also just upgrade your conventional boiler and go for a unvented tank as theses are alot better then a copper cylinder for water pressure and efficiency and you lose all the plastic tanks . but i think you be better going for a combi for a small house.

Banned

kash2013

I am a plumber, i would recommend a good quality combi like vaillant also … I am a plumber, i would recommend a good quality combi like vaillant also i would also recommend a Worcester boiler but these tend to be more complicated to fix if they do go wrong. You can not beat conventional for reliability as its all separate and less parts to go wrong. You can also just upgrade your conventional boiler and go for a unvented tank as theses are alot better then a copper cylinder for water pressure and efficiency and you lose all the plastic tanks . but i think you be better going for a combi for a small house.



luck of the draw. my mum owns 2 houses both with worcester boilers. Both less than 4 years old and both have broken down more than once.

Combi boiler. They are sized on hot water not radiators - the bigger the size the more hot water it can produce instantaneously at a hot tap. I would recommend a 30kw, any more is pointless, less is pretty poor in the winter when the incoming main is at its coldest.

A combi is only marginally less reliable than a heat only. A boilers reliablity is all dependant on the quality of the install, pay an independent installer to fit it properly. That being said avoid Worcester (the worst boilers on the market to repair, and overpriced), and anything Italian/French.

Look at ATAG, Intergas, Ideal, Viessmann and Vaillant (probably in that order).

go for potterton boilers....cheap and cheerful.

go for potterton boiler cheap and cheerful.

i love having a combi
great knowing you are only heating water when you actually use it. was always a pet peeve of mine when we went away and i knew it was heating up water for the next day and i wasnt their to use it!

ratsdomino

i love having a combigreat knowing you are only heating water when you … i love having a combigreat knowing you are only heating water when you actually use it. was always a pet peeve of mine when we went away and i knew it was heating up water for the next day and i wasnt their to use it!


Exactly, and the fact you have to put hot water on for like 2 hours before you can have a bath or shower.

Can you have a power shower with a combi boiler, was told you need a conventional boiler for that.

Banned

Daytrader

Exactly, and the fact you have to put hot water on for like 2 hours … Exactly, and the fact you have to put hot water on for like 2 hours before you can have a bath or shower.



I must admit we have only had a combi 2 weeks and I am loving instant constant hot water.

lukeybuilder

I must admit we have only had a combi 2 weeks and I am loving instant … I must admit we have only had a combi 2 weeks and I am loving instant constant hot water.


Yeh its great, with a conventional you have to have it on like 2 or 3 hours even in the summer and you might then not even use all the hot water, does your combi give a good pressure on your shower as well ? im wanting to get a power shower but not sure you can with a combi, as i think you need a tank of hot water for them.

Banned

We have bath only. And the water pressure is a bit low really. flow rate is 9.8 litres per min. It's the only drawback.

Original Poster

yes it bit expensive here in Scotland.

Just to add a combi won't save much on hot water over a conventional, sometimes it will average out costing more. I can run my hot water every other day for a single hour and get enough hot water for 2/3 showers per day. Combi boilers are ~70% efficient in hot water mode, and you also use more water if you are on a meter waiting for the lag in the boiler heating water.

A power shower is a pumped shower. You don't need one with a combi because hot and cold are already at mains pressure.

But every shower i have seen working on a combi boiler seems to trickle out of shower head, i mean not alot of pressure, our power shower on full can almost knock you over, i cant see tap pressure doing that on a combi, oh, and i have to have hot water on for 3 hours a day, and that is just enough for 1 shower and nothing else, not even hot water for washing up etc, mind you i shower for at least 15 minutes.
Edited by: "Daytrader" 30th May 2015

if you decide to buy a combi then avoid cheap boilers and stay with a well know brand and certainly avoid Veismann, not many engineers know this boiler and when it breaks down you will struggle finding an engineer.

stick with, Wocester bosch (top of the range), vailant, Baxi or Potterton, all come with 5+ year warranty.
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