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Original poster

Installing combo boiler and removing tank cost

34 replies

Mollyeyes · 26/04/2021 18:11

Hello
Has anyone replaced a standard boiler with combi boiler in kitchen and removed water tank (and pipe work) from a cupboard in upstairs bedroom cupboard? Just wondering on rough cost to remove old boiler, install combi and remove tank please? In Surrey area. Thank you

OP posts:
emmathedilemma · 26/04/2021 18:13

yes but it was a few years ago and from memory around £4500 but a large part of that was scaffolding hire as I'm on the first floor and they had to use it to install the boiler flue to outside.

mobear · 26/04/2021 19:34

I don't but we are looking at doing similar work and our plumber told me that if we want to use both bathrooms at the same time we will probably still need a water tank. We are going to move it into the loft though.

eyebagsandgladrags · 26/04/2021 19:40

I'm getting this done soon. We're also having a few radiators replaced and have upgraded to a more expensive system flush, but I think the combi boiler installation + tank removal comes to about £3500.

LivingDeadGirlUK · 26/04/2021 19:41

I'm getting a quote for this tomorrow actually but am expecting it to be around £3k. 3 storey house though. Will report back :)

Sometimes123 · 26/04/2021 21:27

We did this in 2018. We were not expecting to have to do it, but when fitting spot lights in the kitchen our electrician noticed the timber in the ceiling joists were wet...turns out the water tank was leaking in the bedroom above.

We hadn't budgeted for the work, so we got a 0% credit card and asked our plumber to go to the merchants and order what he needed for the job. (Very trustworthy guy by the way) we then paid for the boiler and everything else on the credit card...came to about £ 2000 + vat. He did the work for £1700. Plus we took the old water tank to the scrap metal merchants plus some old copper piping that the plumber had found in the floor and got approx £170 for it.

Tibtab · 26/04/2021 21:30

In the SW, we have had quotes from £3800-4500

celandiney · 26/04/2021 21:37

I wish to goodness we had a tank ( moved into a house that had bern renovated - they took the tank out...)
Water pressure means you can't do more than one water using activity at once (good luck sometimes washing your hands upstairs if someone has flushed the loo downstairs)
And if the water goes off you ( obviously ) have no water at all.
Such a pain.
I'd have a hot tank back as well if I could,as the amount of water that gets wasted waiting for the hot water to run hot must be excessive.

Mumski45 · 26/04/2021 21:50

I would never replace our tank with a combi. I just don't get how it could work for us trying to use more than one tap/shower at a time. We have just replaced our 22 year old boiler which really was on its last legs for around £700-800. DH managed to pick up a bargain nearly new but second hand one on eBay for around £250. A local plumber fitted it and flushed the heating system for around £500. I couldn't believe it worked when it was finished and luckily I had kept my scepticism to myself just in case he managed to pull it off.

LivingDeadGirlUK · 27/04/2021 07:45

My problem is that the existing tank isn't big enough to fill the bath. For no good reason other than cost either as its in quite a large cupboard upstairs! If it turns out we can't get the pressure from a combi for our upstairs shower, I think we will need to have a bigger tank put in.

riddles26 · 27/04/2021 12:33

Unless you have a very small property, I would not replace a tank with a combi. We had a combi and the water pressure did not allow toilet to be flushed when someone was in the shower. Likewise for washing machine to be used and kitchen tap to be turned on. If there are just 2 of you and its a small place, it is inconvenient but manageable. With a family, it is a massive pain and I definitely would not recommend it

Tangledtresses · 27/04/2021 12:38

We've got a combi by valiant that has a tank for houses with more than one bathroom
It's great! No cold shower issues etc

When we removed out old tank system beware you will have to change you piping if it's old as it won't stand the pressure
Whole house new rads pipes etc £4/5k

FurierTransform · 27/04/2021 12:40

Just upgrading the tank to a bigger one is a far cheaper job.
I'd only ever get a combi if you have grand plans for the airing cuboard where the hot water tank currently sits - walk in shower/ensuite or simiar. It's an expensive downgrade in many ways otherwise.

Ajahd · 27/04/2021 12:44

We had ours done in December for £3800. But ours was a nightmare because they didn't adjust the flow, so we struggled for hot water for 3 months because the guy was unreliable and would say he'd come back but then wouldn't. Research what boiler you want, he used a cheap boiler (that's what I've been told by the plumber I had to employ to fix the problem in the end). Because the boiler is so small and rubbish, it is set to 6L per second, which takes forever to fill a bath.

It is only my husband and I with our 7 month old, so can't say we've noticed many issues with not being able to have hot water in multiple rooms. We only have one bathroom.

kizkiz · 27/04/2021 13:10

We did it in 2018. 3 storey house. Removed all existing plumbing, boiler, tanks, rads. All new pipework, 10 new radiators, combi boiler. £6500.
Only one bathroom, so no issues with multiple showers. Pressure is excellent, and multiple things can be used at the same time with only a very slight drop in pressure. We gained a bathroom cupboard and huge cupboard that the tank sat in

Original poster
Mollyeyes · 27/04/2021 16:30

Thank you everyone, very useful advice. It is a 2 bed house with one bathroom and downstairs toilet too. Only 2 of us, we mainly have showers.
@kizkiz what combi make did you go for? Thank you

OP posts:
kizkiz · 27/04/2021 16:59

@mollyeyes it's a Worcester bosch. I'm also in Surrey btw

40somethingJBJ · 27/04/2021 18:31

I did this last October. Cost around £3500

LivingDeadGirlUK · 27/04/2021 18:58

Well I said I would report back, the verdict is that we can't get a powerful enough combi boiler to serve our 3 storey, 2 bathroom house without upgrading the incoming gas main. I've discounted this option as it would mean taking up the tiled floor through the ground floor, and its the only flooring in our house that doesn't actually need replacing!

Now getting a quote for a new system boiler and bigger hot water cylinder.

rwalker · 27/04/2021 19:03

@LivingDeadGirlUK
I'd double check what plumber meant because they changed the spec on gas pipes a few years ago. They have to meet new standards irrespective of what boiler you go for .

LivingDeadGirlUK · 27/04/2021 19:19

[quote rwalker]@LivingDeadGirlUK
I'd double check what plumber meant because they changed the spec on gas pipes a few years ago. They have to meet new standards irrespective of what boiler you go for .[/quote]
I've just had a look and the regs say 22mm is the minimum size allowed for domestic so we should be ok!

LivingDeadGirlUK · 27/04/2021 19:20

I really want a bath now :/ just the thought of sitting in half a bath of warm water or a full bath of tepid water puts me right off :p

Original poster
Mollyeyes · 28/04/2021 06:56

Thank you everyone much appreciated. Sounds like we need to budget between 3-4K.

OP posts:
Flapjak · 28/04/2021 07:24

Just been quoted 4.5k to go from reg boiler to combi. Am worried about comments about piping, not enough water to flush loo and have a shower. I have been reassured by all the people who have had a quote that isnt a problem with a good combi these days. Any experts on here know that if we are replacing a standard boiler to combi that all pipework should be changed or just the gas pipe

LivingDeadGirlUK · 28/04/2021 09:07

@Flapjak

Just been quoted 4.5k to go from reg boiler to combi. Am worried about comments about piping, not enough water to flush loo and have a shower. I have been reassured by all the people who have had a quote that isnt a problem with a good combi these days. Any experts on here know that if we are replacing a standard boiler to combi that all pipework should be changed or just the gas pipe
I think its two separate issues tbh, the gas upgrade is because the combi boiler does all the circulation, there are no additonal pumps, so if you have multiple bathrooms/floors you need a bigger boiler to circulate the hot water.

The issue about flushing the loo, which is only drawing cold water, sounds like there is not enough water pressure from the main water incomer to support running the boiler and filling the cistern/running a tap. Some water incomers have a gauge on them that will tell you the pressure, if not your plumber should be able to measure this and confirm. If you have low water pressure a combi may not work.

TobyHouseMan · 28/04/2021 09:19

If you have a problem with your shower when flushing the loo then it may not be the water pressure itself which is the problem bit rather the size of the incoming main into the house.

A 15mm pipe can only supply a fixed amount of water regardless of the incoming pressure (gross simplification). If your incoming water pipe is 15mm then this could potentially cause you problems with a combi.

If your changing to a combi then the first thing a plumber should do is determine the pressure and the flow rate into the property.