New Boiler

RJ82

Hi there,

I'm looking to get a rough ball park figure for upgrading the central heating system.

The house in question is a 3 bed end terrace. The current central heating is being provided by a back boiler unit (i think) with an immersion heater in the spare bedroom and cold water tanks in the attic.

How much roughly would it cost to change it to a condensing boiler?

D_M_E

Depends on how many radiators you have, what the output of the boiler is, how much pipework is needed and various other factors.

Probably £3000 to £5000 for a brand new installation from scratch and that should include removal of the tanks in the loft.

Eric_Disley

I had a back boiler replaced with a mid-range combi boiler for £2k so it might not be that high. You won't know for certain until an engineer looks at exactly what's involved. Get several quotes.

matelodave

I'd guess around £2-3k depending on what sort of boiler you have fitted, where the new one is going to be installed and how much plumbing that has to be re-routed.

Don't get confused by condensing and combi (combination boilers).

All boilers have to be condensing boilers nowadays and will usually have to be installed on an outside wall otherwise it can work out expensive for the flue and condensate drain.

A combi heats water on demand and doesn't need tanks in the loft nor a hot water tank.

The other sort is a system boiler which will usually utilise tanks in the loft and will have a hot water tank in the airing cupboard.

Raxiel

I paid £2600 for mine at the end of 2015 but every situation is different.

We had an old wall mounted boiler and gravity system (tanks in loft and airing cupboard) removed and replaced with a Worcester Bosch CDi-32 compact condensing combi boiler.

The work involved removing the old boiler and tanks, and fitting the new boiler and magnetic filter in a different location (about 5 meters away on the same wall) and all the new pipework involved in that (including opening a boxed in part of the kitchen and running pipes inside). I kept all the existing radiators but had a small extra rad fitted in the airing cupboard. They also fitted a Smart thermostat.

I got three quotes, two local companies (both Worcester Bosch approved and on the councils trusted trader register) quoted me about £2600 (looking at prices online I'd guess they were close to 50:50 parts and labour), and British gas, who quoted £5000. The guy from BG did admit that figure included a big contingency due to the relocation in case they lifted the boards or opened the box-in and it was harder than expected to re-route pipes, but there's no guarantee they'd have cut the final bill if it all went smoothly.

BG also suggested a chemical flush, both local companies stated that unless I had problems with cold spots a chemical flush wasn't needed, and that even a power flush was only recommended if the old system was particularly silted up. The firm I went with in the end said they'd do the power flush at no extra charge if needed but on the day the guys judged it unnecessary (I watched them work and the old drain water and removed pipework all looked clean so I don't think they were sherking).

This was in Derbyshire, I imagine other parts of the country could be more expensive for labour.

The moral is, get several quotes, and make sure one or more are local independents, not just national chains with big advertising budgets. I expected BG to be more but I was stunned at the difference.

Edvin_Paus

Hi RJ82,

It can range between £2000 to £6000. It depends on the size of your home. They ask such questions depending on how many bedrooms your home has? Also how many bathrooms does your home have? Do you have a hot water cylinder?

The price also varied if you are paying it off in one go or on monthly basis.

Hope this helps. Let me know if you have any other questions.

:money:

teddysmum

I never even considered approaching the likes of BG and Npower, but had prices varying by 30% from independants. We have a WB combi and found that WB accredited fitters were the more expensive ones, as they have to pay fees to WB.

daveyjp

Nice ad, however my advice is don't go near helplink.

sarah1972

Meghanjrobinson reported for spamming the boards

C_Mababejive

I know this is the subject of common debate ut i do feel more people should seriously consider whether their new boiler should be a heat only /system boiler and not a combi boiler.

My hot water is heated by a gas wall mounted boiler currently rated at around 9 Kw or 30,000 Btu/hr. It feeds a well lagged storage cylinder on the first floor.

The hot water temperature at my taps is currently 50 C. The temperature at my cold tap is 5C

The response rate from tap on to hot water is quite swift and i can easily run a nice deep bath and wallow in it.

Now then, let us look at combi boilers.

Well if we look at a high spec high output combi boiler lets take the Vaillant Eco tec plus,a well respected brand and an excellent product.

The tech spec for the biggest(?) one in the range, the 38Kw model ,specifies that it can deliver 13 litres a minute raised 42C .

Of course there will be some inertia in reaching this final output figure and it very much depends on many factors. It could take a few minutes and as you wait, your water is running down the drain taking with it the heat it contains . Note that as soon as you turn the hot tap on, the boiler will likely soon climb to full output.

Most combis have a more realistic temp rise figure of maybe 35 C

So on a cold day like today, i can have hot water at 50C quickly and with a 9Kw input boiler, whereas modern combi users can at best have water at the tap of 47 C after a wait from 38Kw input and more typically, water temp at the taps of 40C with an average combi.

But what other factors are at play? Well consider your fire breathing 38Kw combi. When it fires up as you go to wash the dishes or have a shower ( can you do both at the same time?), it is pulling gas from the network. Mostly the network was designed and installed years ago, long before mass marketing of combis.

Maybe everyone in your are is also trying to have a shower or do washing up with their combis?

Chances are you will all be running on sub optimal gas inlet pressure so boiler output will be reduced. This slows responsiveness and reduces final hot water output temp.

In summary, i am a great advocate of stored hot water in many family homes, fed by high efficiency heat only/system boilers and not combis.

It also does the heating