is a 24kw boiler big enough for a 3 bed house??

the_matrix

I've just had a new 23kw installed in my rented 3 bed and it's great.

trailingspouse

We have a large 4 bed house, with a 24 kw boiler. When we first moved in I had the Gas Safe guy out to inspect it, and he reckoned we might find it a bit small for the size of the house.

But here we are 18 months on, and there's never been a problem. The radiator in the top bathroom (3 floors up from the boiler) is almost too hot to touch, and there's no problem with hot water. The only problem we have is the length of time it physically takes for hot water to reach the top floor - but once it gets there it's plenty hot enough.

He quoted us £1000 for a larger (32kw?) one, but we really don't feel we need to change it.

bridgedino

Johnandabby wrote: »

How can you possibly know that the house only needs 6-8 kW of space heating??? You don't know the size of the house, the level of insulation provision, how exposed it is, where in the country it is, how big each radiator is etc.

I've recently designed a heating system for a new build 3-bedroom house, and it had a heating load of 25 kW - the previous project was 5 kW for a 3-bedroom house. You can't just guess these things - a Gas Safe engineer or heating engineer needs to visit the property and make a proper assessment, not just guess on a forum

And how do you know it's not?

Im all too well aware of the process for heat loss calculations through building fabric, North facing, windows, roof spaces etc. Don't assume your the only one with an understanding of it.

I stand by my guidance given based on what the OP has said

bridgedino

trailingspouse wrote: »

We have a large 4 bed house, with a 24 kw boiler. When we first moved in I had the Gas Safe guy out to inspect it, and he reckoned we might find it a bit small for the size of the house.

But here we are 18 months on, and there's never been a problem. The radiator in the top bathroom (3 floors up from the boiler) is almost too hot to touch, and there's no problem with hot water. The only problem we have is the length of time it physically takes for hot water to reach the top floor - but once it gets there it's plenty hot enough.

He quoted us £1000 for a larger (32kw?) one, but we really don't feel we need to change it.

An excellent example

Johnandabby

bridgedino wrote: »

And how do you know it's not?

Im all too well aware of the process for heat loss calculations through building fabric, North facing, windows, roof spaces etc. Don't assume your the only one with an understanding of it.

I stand by my guidance given based on what the OP has said

But I'm not plucking numbers out of thin air, so i don'thave to prove anything. You might be right, but expensive mistake if it's not looked at properly.

I have to assume that you don't have any understanding of it based on your response - you cannot size a boiler based on '8 rads 3 beds'.

But actually I looked in a crystal ball this morning and I'm 100% sure that the op needs a 18 kW system boiler and 180 litre cylinder....

karenann76

Thanks to you all for your posts, I appreciate it!

We have been quoted £450 for the swap over. I thought that was a bit steep!

karenann76

If I wasn't so cold I might leave it till after Christmas!!

maninthestreet

I have a 16kw boiler in my 3 bed house, and it seems to be adequate.

CrazyRed

Up until it died at the end of July, I had a 16Kw boiler here, with hot water tank (3 bed house, double glazed, cavity wall insulated, South East, 8 radiators) which was more than adequate for both heating and hot water.

Unfortunately, we became victims of 'policy' when the old boiler went south, and ended up with having to have a combi boiler, thus the tank and associated piping and electrical gubbins got removed and [STRIKE]binned[/STRIKE] recycled for scrap.

Hanging on the wall now is a WB 24i "Junior". AIUI Maximum output of 24Kw and I can assure you that it is more than plenty to cope with the heating load of this house - if anything, it's cycling far less than the old boiler used to, yet the house is more than plenty warm enough - 22.5-24C is easily achievable and maintainable with the boiler only cycling 2-3 times an hour.

Hot water isn't quite as good as the original setup, although to be fair, the available pressure is considerably higher, thus the flow appears better. It just doesn't get as hot as the old tank water seemed to - shaving, for me, now is a matter of luke-ish warm water, not "oosh that was rather warm" as it was prior.

BristolS

CrazyRed wrote: »

Up until it died at the end of July, I had a 16Kw boiler here, with hot water tank (3 bed house, double glazed, cavity wall insulated, South East, 8 radiators) which was more than adequate for both heating and hot water.

Unfortunately, we became victims of 'policy' when the old boiler went south, and ended up with having to have a combi boiler, thus the tank and associated piping and electrical gubbins got removed and [STRIKE]binned[/STRIKE] recycled for scrap.

Hanging on the wall now is a WB 24i "Junior". AIUI Maximum output of 24Kw and I can assure you that it is more than plenty to cope with the heating load of this house - if anything, it's cycling far less than the old boiler used to, yet the house is more than plenty warm enough - 22.5-24C is easily achievable and maintainable with the boiler only cycling 2-3 times an hour.

Hot water isn't quite as good as the original setup, although to be fair, the available pressure is considerably higher, thus the flow appears better. It just doesn't get as hot as the old tank water seemed to - shaving, for me, now is a matter of luke-ish warm water, not "oosh that was rather warm" as it was prior.

Have you tried not having the hot tap fully open?
A lower flow will mean hotter water. Also insulating the hot water pipe will reduce the heat lost from the boiler to the tap