Boiler size.

johneym

hello all,

I have 8 radiators all around 1000mm long.3 are double. Well insulated smallish house and smallish cylinder.

what might be an efficient size indoor boiler non condensing.

Thanks a lot.

slimjimmc

Is there any reason why you're specifying a non-condensing? Building regs require the boiler be a condensing model where possible.
http://www.seai.ie/Power_of_One/Heat_Your_Home_For_Less/Replacing_Your_Boiler/

Since March 31st 2008 when installing a replacement oil or gas boiler it is now a requirement that the boiler be condensing, where practical (Section L3, Building Regulations Part L amnement – S.I. No. 847 of 2007:- http://www.environ.ie/en/DevelopmentHousing/BuildingStandards/) - See more at: http://www.seai.ie/Power_of_One/Heat_Your_Home_For_Less/Replacing_Your_Boiler/#sthash.LU7x72BC.dpuf

Calahonda52

slimjimmc wrote: »

Is there any reason why you're specifying a non-condensing? Building regs require the boiler be a condensing model where possible.
http://www.seai.ie/Power_of_One/Heat_Your_Home_For_Less/Replacing_Your_Boiler/

He may have an issue with the higher inlet temp that a non condensing boiler produce more easily because the rads may be too small/sized on 85.
eg most Condensing boiler have a normal max of 70/75 whereas many non condensing have 85.
Just a guess

Dtp1979

Calahonda52 wrote: »

He may have an issue with the higher inlet temp that a non condensing boiler produce more easily because the rads may be too small/sized on 85.
eg most Condensing boiler have a normal max of 70/75 whereas many non condensing have 85.
Just a guess

Higher inlet temp?

Calahonda52

Dtp1979 wrote: »

Higher inlet temp?

On the hot pipe to the rads

Dtp1979

Calahonda52 wrote: »

On the hot pipe to the rads

Oh rite.
What would the issue be?
I think all stats are set to 85 max, condensing or non condensing. Maybe I'm wrong

Dtp1979

The only issue I can see with condensing is the plume it emits.
I know grant don't make non condensing anymore so I'd say done deal is OP's only option

johneym

lads,

many thanks for the replies.

I am happy to answer your questions if anyone can answer mine.

John

Dtp1979

johneym wrote: »

lads,

many thanks for the replies.

I am happy to answer your questions if anyone can answer mine.

John

Ok why non condensing? Are you gas or oil?

Kevin McCloud

Firebird kitchen model ftw.

Dtp1979

Ftw?

Dtp1979

Kevin McCloud wrote: »

Firebird kitchen model ftw.

And god no don't choose firebird op

Kevin McCloud

Dtp1979 wrote: »

And god no don't choose firebird op

What is so wrong with a non condensing firebird?

Dtp1979

Kevin McCloud wrote: »

What is so wrong with a non condensing firebird?

It's against building regs and common sense would tell you not to fit a non condensing boiler.

Kevin McCloud

Dtp1979 wrote: »

It's against building regs and common sense would tell you not to fit a non condensing boiler.

Regs how are, this country is gone to the dogs with lads in suits with regs, health and safety and other nonsense. You would swear I was tellng the op to murder some one.
What common sense reasons have you for fitting a condensing over a non condensing? Forget about regs now for a while.

Dtp1979

Kevin McCloud wrote: »

Regs how are, this country is gone to the dogs with lads in suits with regs, health and safety and other nonsense. You would swear I was tellng the op to murder some one.
What common sense reasons have you for fitting a condensing over a non condensing? Forget about regs now for a while.

A condensing boiler is more efficient. I don't think anything else makes more sense than that

Kevin McCloud

Dtp1979 wrote: »

A condensing boiler is more efficient. I don't think anything else makes more sense than that

Equate that into figures, take the standard 3 bed semi, one with a condensing and one without. What is the family with the condensing saving per annum? Use €1000 as a figure for the family with the non condensing.

Egass13

Kevin McCloud wrote: »

Equate that into figures, take the standard 3 bed semi, one with a condensing and one without. What is the family with the condensing saving per annum? Use €1000 as a figure for the family with the non condensing.

Are you trying to say they are the same then ? Or where are you going with this? If you have a SE boiler and it's working perfectly fine , then fair enough , there's probably no reason to upgrade to a HE , given install costs and pay back etc . But if your changing the boiler regardless , what possible reason is there to choose an SE over a HE ?

Kevin McCloud

Egass13 wrote: »

Are you trying to say they are the same then ? Or where are you going with this?

No i am not saying they are the same, i would like to know what saving can be made, if the condensing is more efficient it should save the homeowner money.

Egass13

Kevin McCloud wrote: »

No i am not saying they are the same, i would like to know what saving can be made, if the condensing is more efficient it should save the homeowner money.

And it will . But there is no definitive figure . A lot of factors have to be taken into account

Dtp1979

Egass13 wrote: »

And it will . But there is no definitive figure . A lot of factors have to be taken into account

Ye that

Kevin McCloud

Can we have a guesstimate at least?

Egass13

Kevin McCloud wrote: »

Can we have a guesstimate at least?

Baring in mind this is just a guess using some rough figures

Dtp1979

Kevin McCloud wrote: »

Can we have a guesstimate at least?

Would you drive from limerick to Dublin in 4th or 5th gear?

Kevin McCloud

Dtp1979 wrote: »

Would you drive from limerick to Dublin in 4th or 5th gear?

Neither I would drive in 6th, you seem to think im disputing that a non condensing would be as efficient as a condensing.

Dtp1979

Kevin McCloud wrote: »

Neither I would drive in 6th, you seem to think im disputing that a non condensing would be as efficient as a condensing.

That's the way it's coming across.

Kevin McCloud

Dtp1979 wrote: »

That's the way it's coming across.

My apologies never was intended that way.

pat35

ballpark 20 percent

JustTheOne

Sorry to bring up thread.

Would an 18Kw gas boiler be sufficient for 8 rads in a normal 3 bed semi d with an extension or would a 24kw be more suitable?

Thanks.

van_beano

JustTheOne wrote: »

Sorry to bring up thread.

Would an 18Kw gas boiler be sufficient for 8 rads in a normal 3 bed semi d with an extension or would a 24kw be more suitable?

Thanks.

My tuppence worth and It's probably overkill but I'm getting a 30kw installed for 12 rads

JustTheOne

van_beano wrote: »

My tuppence worth and It's probably overkill but I'm getting a 30kw installed for 12 rads

Thanks for that.

Egass13

JustTheOne wrote: »

Sorry to bring up thread.

Would an 18Kw gas boiler be sufficient for 8 rads in a normal 3 bed semi d with an extension or would a 24kw be more suitable?

Thanks.

18kw is More than sufficient.

JustTheOne

Egass13 wrote: »

18kw is More than sufficient.

That's great thank you.

Dtp1979

van_beano wrote: »

My tuppence worth and It's probably overkill but I'm getting a 30kw installed for 12 rads

Why?

Egass13

Dtp1979 wrote: »

Why?

Sure don't they modulate

van_beano

Dtp1979 wrote: »

Why?

No idea, I'm no boiler expert. Is 30kw to much for 12 rads over a 170m2 2 storey house?

Dtp1979

van_beano wrote: »

No idea, I'm no boiler expert. Is 30kw to much for 12 rads over a 170m2 2 storey house?

Unless they'd gigantic rads yes it's watyyyyy to big. Did your Rgi not advise you against this??

van_beano

Dtp1979 wrote: »

Unless they'd gigantic rads yes it's watyyyyy to big. Did your Rgi not advise you against this??

Funny you should say that, it was the RGI who recommended it, I would have thought 24kw would be enough. They're only normal radiators, 4 doubles and 8 singles. You may be saving me a couple of quid here, DTP!

Dtp1979

van_beano wrote: »

Funny you should say that, it was the RGI who recommended it, I would have thought 24kw would be enough. They're only normal radiators, 4 doubles and 8 singles. You may be saving me a couple of quid here, DTP!

In the price of the boiler and years of gas wastage. A 24kw would be loads.
It's not a combi yiur fitting is it?

van_beano

Dtp1979 wrote: »

In the price of the boiler and years of gas wastage. A 24kw would be loads.
It's not a combi yiur fitting is it?

Not a combi, just a regular condensing gas boiler. It's a replacement for my current Poterton boiler. Got a quote from a particular utility and it was for the 30kw "Ideal" boiler with 2 controls (heat & water, 3 controls would involve taking up floorboards as house isn't compatible for it in its current layout), TRV's on each rad, chemical flush, some magnet box attached to the boiler and a small bit of pipe work needed to the cylinder in the hotpress. Final price after grants and "discounts" subtracted - €2460

As you can tell, I'm no expert on these things so any advice on the above would be much appreciated!

Dtp1979

van_beano wrote: »

Not a combi, just a regular condensing gas boiler. It's a replacement for my current Poterton boiler. Got a quote from a particular utility and it was for the 30kw "Ideal" boiler with 2 controls (heat & water, 3 controls would involve taking up floorboards as house isn't compatible for it in its current layout), TRV's on each rad, chemical flush, some magnet box attached to the boiler and a small bit of pipe work needed to the cylinder in the hotpress. Final price after grants and "discounts" subtracted - €2460

As you can tell, I'm no expert on these things so any advice on the above would be much appreciated!

Ring 3 local rgi's and get prices.

roy rodgers

van_beano wrote: »

Not a combi, just a regular condensing gas boiler. It's a replacement for my current Poterton boiler. Got a quote from a particular utility and it was for the 30kw "Ideal" boiler with 2 controls (heat & water, 3 controls would involve taking up floorboards as house isn't compatible for it in its current layout), TRV's on each rad, chemical flush, some magnet box attached to the boiler and a small bit of pipe work needed to the cylinder in the hotpress. Final price after grants and "discounts" subtracted - €2460

As you can tell, I'm no expert on these things so any advice on the above would be much appreciated!

What grants are they giving you?

cerastes

do people think its a matter of matching the boilers to the radiators and not sizing everything to the requirements of the characteristics of the property?
From what I've gathered is, you need to be able to meet the heating demand at the peak demand, while being able to fulfil the demand efficiently at all or most other lower demands.
To me that means operating the smallest possible boiler that you could need so it operates efficiently for most of its use.
Contrary to this I've heard advice to get more capacity than is needed just in case or to make sure you have enough heating ability instead of working it out and only getting the absolute maximum needed.
I'm not even convinced the maximum combined heating ability should include extreme conditions unless the minimum demand can be met efficiently.while I'm sure modulating boiler can do that, I think its better to work it out and determine it.

Do boiler manufcturers provide tables to assist installers to determine the right boiler size?

van_beano

roy rodgers wrote: »

What grants are they giving you?

The €700 + €50 BER seai grant and approx €390 from themselves, roughly €1140. It was €1000 but the grants have changed within the last week to add €140.

JustTheOne

So am I still good with 18kw:)?