is my boiler powerful enough?

searchlight123

in feb 2009 i had a new boiler (not combi) fitted in my house by british gas. (did shop around but at that time prices were all quite similar).
i live in an extended 4 bedroom detached 1980's built property in the south-east. they fitted a baxi 15HE boiler. it has been working fine but recently checked on the baxi website and the 15HE is recommended for a 2 bed flat!! now i'm concerned that my boiler is overworking and so will wear out prematurely. could that be the case?
we have 14 rads (although we don't use the en suite or bathroom ones as it is hot enough in there).
hot water is supplied via a tank in the loft and a hot water cylinder in an airing cupboard in the bathroom.
i would appreciate your thoughts before i question the validity of the advice i received from BG.
many thanks.

*j*

I think the only question is:

Does the boiler heat the house up to the required temperature?

*j*

Canucklehead

Hi: in addition to Post 2, what model did your current boiler replace? What improvements in terms of insulation etc have been undertaken since the house was built?

Canucklehead

anotherbaldrick

I would have though a 15 Kw boiler for a 4 bed undersized, we have 24 Kw for a similar sized property (14 rads)and we are insulated to cat "C"

searchlight123

*j* wrote: »

I think the only question is:

Does the boiler heat the house up to the required temperature?

*j*

hi
yes the house is heated to a good temperature. my concern though (if the boiler is under sized) is if it ius overworking to achieve these results which could in turn lead to premature wearing out?

the boiler it replaced i am ashamed to say i do not know. it was the original one fitted at new in 1986 and was (i am told) highly inefficient.

insulation in the house is good. cavity wall insulation and loft area well insulated. house double glazed also.

thanks again.

*j*

Hi TG,

If you are happy with the temperature of the house, then I wouldn't worry.

Boilers work at their most efficient when they are working at near maximum capacity, I believe.

If it is working reliably, then don't fret about it, and don't talk yourself into a new (expensive) one!

Just think yourself lucky that you can keep your house up to temperature with only 15Kw of energy.

*j*

macman

Even if it is going to expire earlier than it otherwise might (no way of knowing that), there is no point in replacing it until it does! Just get an annual service from a local independent GSR RGI and let it do it's job.

anotherbaldrick

*j* wrote: »

Hi TG,

If you are happy with the temperature of the house, then I wouldn't worry.

Boilers work at their most efficient when they are working at near maximum capacity, I believe.

If it is working reliably, then don't fret about it, and don't talk yourself into a new (expensive) one!

Just think yourself lucky that you can keep your house up to temperature with only 15Kw of energy.

*j*

Unless you have a modulating boiler which the Baxi isn't , their is no such thing as working "at or near maximum capacity" The boiler is either on or it is off. With an undersized boiler, in very cold weather the problem will be the time taken to get the property up to temperature from cold and this will of necessity lead to the boiler having to be on nearly all the time. With a more adequate boiler you can afford to leave the boiler off at night and in the mornings when you are moving about and only flick the heating on when you are about to sit down to eat and rest knowing it will take about 20 mins to get the temperature up. This linked to good insulation gives better economy and lower fuel costs

*j*

anotherbaldrick wrote: »

Unless you have a modulating boiler which the Baxi isn't , their is no such thing as working "at or near maximum capacity" The boiler is either on or it is off. With an undersized boiler, in very cold weather the problem will be the time taken to get the property up to temperature from cold and this will of necessity lead to the boiler having to be on nearly all the time. With a more adequate boiler you can afford to leave the boiler off at night and in the mornings when you are moving about and only flick the heating on when you are about to sit down to eat and rest knowing it will take about 20 mins to get the temperature up. This linked to good insulation gives better economy and lower fuel costs

Absolutely correct, anotherbaldrick.

*j*

searchlight123

anotherbaldrick wrote: »

Unless you have a modulating boiler which the Baxi isn't , their is no such thing as working "at or near maximum capacity" The boiler is either on or it is off. With an undersized boiler, in very cold weather the problem will be the time taken to get the property up to temperature from cold and this will of necessity lead to the boiler having to be on nearly all the time. With a more adequate boiler you can afford to leave the boiler off at night and in the mornings when you are moving about and only flick the heating on when you are about to sit down to eat and rest knowing it will take about 20 mins to get the temperature up. This linked to good insulation gives better economy and lower fuel costs

i appreciate the comments.
i have to say that the house warms up very quickly and even in this cold spell we only have the heating come on just under an hour before we get up in the morning and about the same before we come home from work. the dial room stat in the lounge is only set at around 15 degrees (don't know how accurate that is because it seems a low number but the house gets very warm on this).
my issue wasn't that the boiler under performs, just that i was concerned about it 'overworking' and wondered if the original advice given to me that recommended this boiler was correct or not?
thanks again for your informative input.

HappyMJ

If the house warms up quickly then it's sized correctly. My house is a 3 bedroom semi and it has a 12kW boiler and it's fine. It can easily heat the living areas to 21 degrees and upstairs bedrooms to 18 degrees on very cold days as it was designed to do.

Don't worry about overworking. It's probably (my opinion) better for it when set on a low temperature and running constantly than a high temperature and cycling on and off.