Intergas Compact HRE SB 30 boiler output

[NLD]

I'm looking to get my boiler changed in the coming week and everyone seems to have there own opinion with what is a good brand/model and what is a bad one.

On balance I'm getting a good vibe about Intergas, but I'm a bot concerned that the output of the Compact HRE SB 30 boiler is rather low (26.6 kW) when compared against other 30kW boilers, which does seem a bit odd. Anyone care to comment why this is?

I have a 1970's built 5 bedroom property with two bathrooms. I do not want to use an undersized boiler as many of the radiators here are massive!

Would I be better off using the larger Intergas Compact HRE 40 SB boiler, even though it will be oversize?

I am considering other boiler brands but I'm just curious why the output of the Intergas 30kW boiler seems to be lower than the competition.

I will be using an Ariston Aquabravo itsi 210 unvented indirect cylinder for DHW storage. Solar panels will be added at a later date.


Thanks

 

[doitmyself]

I'm a bit concerned that the output of the Compact HRE SB 30 boiler is rather low (26.6 kW) when compared against other 30kW boilers.

I have a 1970's built 5 bedroom property with two bathrooms. I do not want to use an undersized boiler as many of the radiators here are massive!

Would I be better off using the larger Intergas Compact HRE 40 SB boiler, even though it will be oversize?

Compact HRE SB 30 is just a name; It could quite as easily been called the Intergas Small.

You can't guess what size boiler you need, and you can't rely on the existing boiler as a guide as many things may have changed since it was installed, e.g extensions, improved insulation etc. The output of existing rads is no guide either as they may be under or oversized. Use the Whole House Boiler Size Calculator to find out what size boiler you need.

 

[NLD]

Thank you for your input.

I have already used the whole house boiler size calculator, which gave a requirement of 30kW.

My question was related to the seemingly low output of the Intergas Compact HRE SB 30 (data on the Intergas website). However some merchants actually quote the output of these as 102364 BTU's which is 30kW.

I appreciate that the actual output is often lower than the 30kW designation the manufacturers often give to their boilers, but the Intergas output is way below what I perceive to be a comparable boiler.

I'm afraid that I do not agree that the 30 does not relate to the boiler size, it clearly does!

 

[lame plumber]

get someone who knows what they are about to do your calcs, I would be really surprised if you need a 30kw boiler for heating, the larger output on combis is there for faster flow rates to you taps and supposedly to enable a couple of outlets to work in unison. the 30kw does relate to the boiler size in that all their boilers have a lesser output than the actual figure shown on the case, as above it is another way of saying small med large. whether you agree or not isnt really worth arguing about though.

 

[Killy Bing]

Have a proper heatcalc done room by room.

what was the output of the old boiler?
and did that preform ok?

30kw is quite a heat requirement for a domestic.
you'll also find most of the radiators are over sized anyway.
not that you should let the rads size the boiler.

its always a bright idea to get insulating to reduce your heat requirement.



Ive actually just input my parents house into the whole house method and got out 34kw

however i know for a fact its 26kw

interesting aye

 

[NLD]

Insulation survey has been done. Cavity wall insulation and additional loft insulation is on its way!

The property is 2,200 sq ft and I have thought about doing some calcs for each room. I don't believe 30kW is over the top for this property.

The existing boiler is an freestanding Ideal Mexico Super 2 RS80, which appears to be rated at 30kW but the output is very inefficient.

Yes with the additional insulation it should require less heating, but cavity wall insulation is not going to improve things drastically, you would need PIR or Phenolic External Wall Insulation (EWI) to make a dramatic change to the U value performance of the total wall.

 

[doitmyself]

I have already used the whole house boiler size calculator, which gave a requirement of 30kW.

My question was related to the seemingly low output of the Intergas Compact HRE SB 30 (data on the Intergas website). However some merchants actually quote the output of these as 102364 BTU's which is 30kW.

30kW is very high, even for a '70s 5 bed house. I only had a 24kW in a large 3 floor 5 bed Edwardian house with solid walls and single glazed wooden windows.

Which merchants said that the output is 102364BTU? (Most merchants now quote in kW, so using BTUs is unusual)

 

[NLD]

30kW is very high, even for a '70s 5 bed house. I only had a 24kW in a large 3 floor 5 bed Edwardian house with solid walls and single glazed wooden windows.

Which merchants said that the output is 102364BTU? (Most merchants now quote in kW, so using BTUs is unusual)

Most merchants only quote the kW rating but some also quote BTU's (which is a simple conversion) like plumbnation.co.uk

I don't necessarily believe what merchants list, as I have noticed that the actual output figures of the boilers are often lower when you look at the manufacturers literature.

Nobody has yet commented why the Intergas has a smaller output than the competition, as it seems to me that all manufacturers do the same sort of range (ie, 12kW, 15kW, 24kW, 30kW).

 

[Dannypipe]

Latest boiler we installed I did a heat calc on the whole (big) house and it came in at something like 27KW. The bloke liked my price and manner and wanted me to do it, but said the other two blokes had quoted for a 42/55 boiler. I asked if they did a heat calc - neither of them did. So I checked all my figures again. Came back in the same ball park. However to keep him happy with have fitted a 42/55KW boiler. Which will be inefficient as it will short cycle (it does) and not properly condense.

The other thing is a margin for error (or safety) is put into most online heat loss calcs, so you don't end up with undersized rads, or boiler. So if you get a figure that is close to your desired boiler, don't be afraid to round down if it's within 5%.

 

[Dannypipe]

Wanted to add, I was going to rate it at 35 by changing the nozzle, but in the end I've left the factory fitted one in there. I'll downsize it on it's next service!! Otherwise I'd never get away. The bloke wants a load more work done.

 

[NLD]

Thanks Dannypipe, I'll measure all the rooms and do a calc today - watch this space!

You are right, nobody who's been to quote for the job has done any calcs. British Gas might have measured the outside walls and counted the number of radiators (there are 15), they quoted for a potterton, max output 30.18 kW, but the price was obviously hilarious!

 

[doitmyself]

Nobody has yet commented why the Intergas has a smaller output than the competition, as it seems to me that all manufacturers do the same sort of range (ie, 12kW, 15kW, 24kW, 30kW).

It doesn't mean there is something wrong with the Intergas; it's just that they decided to make a boiler with 26kW output and call it a "30". The efficiency is virtually the same (within a % or so) as other "30kW" boilers.

15 rads will only add up to about 22-24kW, and certainly no more than 30kW.

Get the cavity insulation done and, if necessary, increase the loft insulation to 300mm. Then recalculate the boiler size.