New boiler

Dave Davenport

Legendary Member
Location
Hampshire
Our boiler (standard gas with hot water tank) was in the house when we moved in 23 years ago, I reckon it's 30+ years old so we're planning on replacing it this summer. Obviously, a new one will be much more efficient anyway but I'm wondering whether to change it for a combi one, are they as reliable as standard ones and are they that much more efficient?
 

twentysix by twentyfive

Clinging on tightly
Location
Over the Hill
Our boiler (standard gas with hot water tank) was in the house when we moved in 23 years ago, I reckon it's 30+ years old so we're planning on replacing it this summer. Obviously, a new one will be much more efficient anyway but I'm wondering whether to change it for a combi one, are they as reliable as standard ones and are they that much more efficient?
Don't do it. I have one of those old ones (fitted pre 1986) and there ain't nothing wrong with it. 98% efficient said the tester man. The newer breed of boiler has a life expectancy much lower than 30+ years. You may get a rather slimmer looking thing but you'll be forever getting the engineer in.

Also there are plans afoot to use hydrogen instead of natural gas in the climate change mitigation process. That may mean another new boiler. I'm hoping I can get a retro fitted burner on my old boiler if that ever happens.
 

Archie_tect

De Skieven Architek... aka Penfold
Location
Northumberland
Hot water flow rate adjusts depending on how many taps/ showers are in use- can affect how quickly thermostatic showers can adjust to change in pressure. Worcester do good ones and have a decent warranty.

If you ever intend to have solar hot water panels on your roof get a 'traditional' boiler with a twin coil cylinder fitted.
 
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Cycleops

Guru
Location
Accra, Ghana
I've just the old Baxi boiler gas system changed to a modern combi condenser one in my house in UK as the old one had just had it. Can't tell you what make it is but cost £4200. There might be grants available for you locally.
 

Levo-Lon

Guru
Spares are the problem.

New combi in the loft should be around £1800- 2.5k plus any new rads and any building work required.

As for efficiency.. You will soon notice the difference :smile:
 
Don't fit it in the loft. You won't be able to get to it when you're older, and British Gas can refuse to service it.

I wouldn't have a combi. You waste a lot of water waiting for the hot tap to run hot. When it does run hot, you have a fairly dismal flow rate. Also, there is much to go wrong. Just get a condensing* system boiler. Best makes are Vaillant and Worcester.

In the unlikely event that hydrogen goes mainstream in our lifetimes, the boiler will just need a new jet in the burner to correct the fuel/air ratio. I remember the town gas to North Sea gas conversion in the 70s. It's also routine to re-jet gas appliances to swap between propane and natural gas.

*you have no choice in the matter anyway
 
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slowmotion

Quite dreadful
Location
lost somewhere
Combis are not more efficient than a normal condensing boiler. They save having a hot water cylinder and its associated standing losses, but the standing losses on a modern foam lagged cylinder are not appreciable. When a combi is just heating domestic hot water (ie the central heating is not on), the boiler fires each and every time you turn on a hot tap. As a result, the "hot water only" efficiency can be lower than 50% in summer.
Central heating installers love combis and recommend them because they are expensive and easy to fit. If you have no room for a hot water cylinder, you pretty much have to get a combi. If you do have space, I would avoid them.

EDIT: Cross post with the excellent advice of @rogerzilla above .
 

iateyoubutler

Über Member
I`ve got a traditional system with a hot water cylinder, and it was all put in when the house was built in 1977. I replaced the boiler around 8 years ago and stuck with the same layout, went for a Vaillant heat only boiler which is so simple and reliable. I`m not a fan of the combi system personally
 

Levo-Lon

Guru
Don't fit it in the loft. You won't be able to get to it when you're older, and British Gas can refuse to service it.

I wouldn't have a combi. You waste a lot of water waiting for the hot tap to run hot. When it does run hot, you have a fairly dismal flow rate. Also, there is much to go wrong. Just get a condensing* system boiler. Best makes are Vaillant and Worcester.

In the unlikely event that hydrogen goes mainstream in our lifetimes, the boiler will just need a new jet in the burner to correct the fuel/air ratio. I remember the town gas to North Sea gas conversion in the 70s. It's also routine to re-jet gas appliances to swap between propane and natural gas.

*you have no choice in the matter anyway

You have to fit a loft ladder, A light. use a gas fitter other than BG.
Loft is ideal place for them.
 

presta

Über Member
I think the decision about a combi revolves around whether you already have an airing cupboard and a tank. I didn't, so a combi was the obvious choice.
 
They are only as good as the installation. IE if you have a power flush / new rads, a magnetic filter, annual service and a decent limescale filter then it should serve you well.

Our Worcester is as above and 8 years on not a single problem.
 

MontyVeda

a short-tempered ill-controlled small-minded troll
Don't fit it in the loft. You won't be able to get to it when you're older, and British Gas can refuse to service it.

I wouldn't have a combi. You waste a lot of water waiting for the hot tap to run hot. When it does run hot, you have a fairly dismal flow rate. Also, there is much to go wrong. Just get a condensing* system boiler. Best makes are Vaillant and Worcester.

In the unlikely event that hydrogen goes mainstream in our lifetimes, the boiler will just need a new jet in the burner to correct the fuel/air ratio. I remember the town gas to North Sea gas conversion in the 70s. It's also routine to re-jet gas appliances to swap between propane and natural gas.

*you have no choice in the matter anyway
Just had a combi boiler fitted last month and the hot water comes through a lot quicker than it used to from the immersion heater... and the flow rate is fantastic in comparison (I still can't quite believe how quickly my kitchen sink fills up).

I guess it's a case of not all combi boilers are created equal.
 

MontyVeda

a short-tempered ill-controlled small-minded troll
Thanks for the replies, I'm tending towards keeping the hot water tank and getting a higher end standard boiler.
my old immersion heater was heating water twice a day that wasn't always being used.... most days it was a couple of sink fulls and the occasional bath full. It seems like such a waste of energy. Heat what you need, when you need it.
 
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vickster

Legendary Member
Thanks for the replies, I'm tending towards keeping the hot water tank and getting a higher end standard boiler.
That's what I did a few years back when. I had new kicthen fitted, Worcester Bosch condensing boiler and a new HW tank, roads all flushed.
Part of the decider for me against a combi was the fact that I'd have to replace my electric power shower
 
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