Combi vs Conventional Boiler???

thechippy

kennyg123 wrote: »

I had an extension about 7 years ago and had a combi fitted. Really was the worst thing I ever did as the thing is so temperamental! When the heating is off, its pot luck as to whether I get hot water or not. My plumber has given up with the boiler and suggests I have a conventional one put in instead. Of course, the tank has now gone, as well as the airing cupboard. We've struggled on as can't afford to change yet!

Maybe you should get in a heating engineer who knows what he's doing?

The most common cause for complaints with combi's are down to a poor initial installation. A cheap / bargain combi. Or, the combi is undersized.

Oh, and "plumbers" who don't know what the are doing....

lurkylurky

We had a new conventional boiler (Worcester Bosch) fitted a year ago and are very pleased with it. Bills have come down, but then so have gas prices. All the plumbers we had quotes from, except one, tried to bulldoze us into having a combi. But we have a large bath and it would take around 20 minutes to fill with a combi, as opposed to the 5 minutes or so it takes now. Not a problem if you showe but I like to wallow in the bath most days.

We have 2 friends closeby and both have had combi's fitted and love them - but they seem to be forever fetching the plumber in to them. And, if there's a cut in the water supply they have no water, whereas we have a tankful. Also, if there is any interruption to the water supply, they have to be rebalanced.

thechippy

lurkylurky wrote: »

We had a new conventional boiler (Worcester Bosch) fitted a year ago and are very pleased with it. Bills have come down, but then so have gas prices. All the plumbers we had quotes from, except one, tried to bulldoze us into having a combi. But we have a large bath and it would take around 20 minutes to fill with a combi, as opposed to the 5 minutes or so it takes now. Not a problem if you showe but I like to wallow in the bath most days.

We have 2 friends closeby and both have had combi's fitted and love them - but they seem to be forever fetching the plumber in to them. And, if there's a cut in the water supply they have no water, whereas we have a tankful. Also, if there is any interruption to the water supply, they have to be rebalanced.

The re-balancing makes no sense at all! - Probably a load of old bull from one of our wonderful "plumbers" to extract some more cash from the unknowing.

A "correctly" sized combi would fill your bath at the same rate as your existing system.

lurkylurky

thechippy wrote: »

The re-balancing makes no sense at all! - Probably a load of old bull from one of our wonderful "plumbers" to extract some more cash from the unknowing.

A "correctly" sized combi would fill your bath at the same rate as your existing system.

Thanks. I shall pass your comments on to the friends re the rebalancing.

It was British Gas that told me my bath would take 20 minutes to fill with a combi. How gullible am I? But we are pleased with the boiler, and the bills.

thechippy

lurkylurky wrote: »

Thanks. I shall pass your comments on to the friends re the rebalancing.

It was British Gas that told me my bath would take 20 minutes to fill with a combi. How gullible am I? But we are pleased with the boiler, and the bills.

Hiya,

As long as you are pleased with the result, that's the main thing........;)
Never believe BG........:eek:

Take care......:beer:

Oldernotwiser

lurkylurky wrote: »

But we have a large bath and it would take around 20 minutes to fill with a combi, as opposed to the 5 minutes or so it takes now. Not a problem if you showe but I like to wallow in the bath most days.

But with a combi you can have an enormous bath and top it up (I'm a wallower as well) without taking all the hot water. I think 20 minutes to run a big bath is an exaggeration but, even if that is the case, it's a small price to pay for limitless hot water.

Canucklehead

Good morning: excellent source of accurate info on heating systems here.

HTH

Canucklehead

Cardew

bockster wrote: »

we had combi about 18m ago and i'm thrilled with it, especially from a financial point of view. its 37kw vaillant, 4bed detatched, 2 adults, 2 kids.
our annual gas usage was in the region of 16600kwh's, (admittedly when energy was cheaper and i was a little less focussed on money saving).

usage this last year was 6600kwh's, at, lets say 3.8p/kwh, thats a saving of £380 p/a. this is being, lets say, quite thrifty with the hot water, indeed in summer the boiler is turned off most of the time and goes on when bath required or dishes need hand washing. (this avoids all the short on/off cycles that usually result in no hot water actually reaching the tap, a lot of combi users will understand what i mean).

i disagree somewhat with the statement that heat loosses from hot water tanks are not so much lost as heat the fabric of the house, although all homes are different. warming the fabric of the house is only useful for the winter months, and even in winter most hot water tanks are upstairs and lost heat will try to escape directly upwards, my old installation as an example, through a pooly isulated section of the loft, what with all the pipes to the tanks and no insulation below the tanks which are invariably in the visinity.

a financial bonus we don't always think of is that theres no pilot light on a combi. i've seen recent posts on here where people suspect the pilot light alone could be costing them about £90pa! perhaps a worst case, but...

so, for me at least, the way a combi works can save you more money perhaps than the energy efficiency of the boiler. our old boiler was approx 73% efficient, new one is 92%ish, as you can see my total reduction in gas usage is much higher than this 19% boiler efficiency gain.

as for running more than one shower, say. our current electric shower is on low power and runs at about 1 l/m, the combi is filling the bath at about 14 l/m even now its colder. i think when i install 2 new showers off the combi it will cope easily.

we also gained an unobstructed loft, an airing cupboard for storage and fitted the combi in the loft freeing space for new kitchen (initial reason for new boiler)

this has been my experiance,
hope it helps,
bockster

The average gas consumption in UK is 20,500kWh.

So heating a 4 bed detached house with 4 occupants with an annual consumption of 6,600kWh - at a cost of approx £200pa is remarkable - especially as it is not a new house. So you are atypical.

Again your post gives the impression that it is the change from conventional to combi boiler that has saved you most of the 10,000kWh and of course it is the efficiency of any new boiler that will be the major reason for any savings for most people. However as said above your consumption is atypical.

Incidentally, some combi's do have a pilot light and others have their own internal HW tank. Although I haven't investigated the subject, I can see no reason why a new conventional boiler need have a pilot light.

Obviously there are advantages having combi, and vice versa, however like so many things on MSE the financial savings are often hugely exagerated.

Also despite what the well respected plumbers, who have contributed above, state, there are strong views amongst plumbers about combi reliability.

'Mike the Boilerman' who seems to have a good reputation for his website states:

Installers often recommend combi boilers because they are quicker, cheaper and easier to fit than non-combis, mainly because here are no tanks to supply and fit in the loft or airing cupboard. It is often not mentioned that they are also more complex and prone to breakdown than non-combi boilers.

http://www.miketheboilerman.com/boilertypes.htm

Jit7

Thanks for all the messages. Bit of a mix bag but it seems most of you like the conventional boilers over the combi's. I'll take a look at the website suggested and get a qualified plumber (or two) around to advise on the type of house we have. I quite like the idea of having more space though by removing the tanks, but we'll see.

Many thanks again for all the replies :j

zzzLazyDaisy

I recently had a new combi fitted and I do like the instant hot water.

But one thing that hasn't been mentioned - my old combi was only 9 years old when it gave up the ghost. I was told by three different plumbers that it wasn't worth repairing as the expected lifespan of a combi is only about 10 years.

This was confirmed by the warm front surveyor (fortunately I discovered I was eligible for a grant for the replacement). But if what I was told is true, then you have to factor in the cost of replacing the boiler every 10 years or so. I don't think that is the case with a conventional boiler.

My sister has a brand new house with a conventional boiler, and it is amazing, the tank heats up in no time at all. I can't remember the name of the type of system but it is a pumped system and copes easily with two bathrooms and two girlies who spend ages in the tub/shower