What size boiler?

PeteW

Hi,

Our old boiler has just died so I'm looking for a new one. Just trying to work out what I need it terms of output.

I've tried a couple of the online calculators but they don't really ask the right questions for a house of my shape, and I'm not entirely sure I'm putting the right details in because the values they output are quite low.

Here's the details of our house.

The house is a three bedroom semi with a flat roofed kitchen extension and then a conservatory behind that.

The footprint of the original part of the house is 7.5x4.5metres. There are two large vertical radiators downstairs.
Upstairs the three bedrooms have a double radiator each.
The kitchen extension is about 4x4.4m. There is no radiator, just a built in electric fan heater.
The conservatory extension is about 4.5x4.5m. It has a glass roof, two glass walls, one breezeblock wall and one transitional brick and window connecting to the kitchen. There is a 1800w vertical radiator in here.

There are two bathrooms which have one radiator, two sinks, a bath and a shower between them.

We have double glazing throughout, cavity wall insulation and an insulated loft.

The two calculators I tried said 8 and 11kw. Which seems lower than any available boiler, which can't be right for a three bed house can it?

Thanks for reading,

Pete

ormus

a vaillant eco tec pro 24 or 28 is suitable for a 3 bed house with two bathrooms.

MX5huggy

The hot water demand is normally higher than the heating demand. So your calculations do not seem far out.

Are you going for a combi or system/regular boiler?

MiserlyMartin

Get a standard boiler not a combi. Too much to go wrong and expensive and complicated to fix. My boiler is a Potterton, and still going strong after 29 years!

karl-123

a mears calculator

costs £20

worth every penny

ormus

MiserlyMartin wrote: »

Get a standard boiler not a combi. Too much to go wrong and expensive and complicated to fix. My boiler is a Potterton, and still going strong after 29 years!

you need to do your sums a bit better.
my condensing combi is 30% more efficient than your old boiler.
with those savings over your costs i could afford to buy a new boiler every 3 yrs.
plus i have instant hot water.
plus i dont have any worries about CW tanks/pipes in the loft to freeze, or hot water cylinders to repair/replace.

NowWhat?

Insert your information in the dropdowns and it will advise you on the best Worcester Bosch product for your requirements.
You also need to consider your hot water demand - how many in the house,age etc as this will also determine your running costs
I am biased and work for Bosch but a combi boiler over a standard boiler is a no brainer - as mentioned by Ormus
Type Worcester Bosch - Find me a boiler in your browser (sorry not able to insert the weblink)

ormus

any CH calculator will return of about 9-12kw boiler requirement. for the average house.
but thats not the whole story. you have to add the DHW on top. plus any spare capacity for any future expansion to the system.
hence you would require say a 24kw combi for a 3 bed semi.

muskoka

VALLIANT are offering FREE 5 yr warranty - parts & labour if fitted before some date in Dec - check our their website - its on there.

ian_w_4

muskoka wrote: »

VALLIANT are offering FREE 5 yr warranty - parts & labour if fitted before some date in Dec - check our their website - its on there.

...only on the plus models, pro models are 3 years. Still not bad though- I'm getting one fitted on Monday!

macman

Combis are spec'd for the required DHW flow, not for the CH output, since you can't have them running both at the same time.