Rad sizing

[LUCIALIA]

What is the best website to use when sizing up a house for radiators?

 

[helpsy]

There was a guide on this site somewhere at some point.Maybe it was only temporary.

Just found it go into plumbing forum and its under sticky threads.

 

[LUCIALIA]

Had a look but couldn't find anything, anyone else with any ideas please?

 

[Billy Bob Bob]

use a mears calculator thats what its for

 

[oldplumber]

yep pay your £50 for a mears and youll be spot on, or get a heating engineer in to do wot he spent years training to do. Sorry if you are a heating engineer, but wouldnt be asking that question, would u

 

[WHPES]

[DLMURL="http://www.theradiatorcompany.co.uk/heatoutput/"]Heat Output Calculator - The Radiator Company[/DLMURL]

 

[Plumbstar Tom]

height(ft) x width(ft) x length(ft) x 5 = BTU ideal for a DIYer

mears calculator = BTU for a proffessional

 

[doitmyself]

height(ft) x width(ft) x length(ft) x 5 = BTU ideal for a DIYer

That formula was around in the 1960's when central heating was becoming popular. Gas was cheap (state controlled) and The Gas Board, who had a monopoly, would advertise "guaranteed temperatures"; which was possible because they oversized the rads and the boiler. The formula makes no allowance for improvement in house design and insulation.

I did a quick "whole house" calculation for a well insulated detached house which is 20ft x 24 ft x 8ft x 2 floors. Using the formula, it works out at 38,400BTU or 11.25kW.

The Sedbuk and EST calculators give a result of 6kW.

I know which one I would trust; and it does not use imperial measurements.

What is the best website to use when sizing up a house for radiators?

Forget the online estimators which make far too many assumptions.

Do a "whole house" calculation using either the Sedbuk Boiler Calculator or the [DLMURL="http://www.energysavingtrust.org.uk/business/Business/Building-Professionals/Helpful-Tools/Whole-house-boiler-sizing-wizard"]EST online boiler calculator[/DLMURL]

If you then deduct 2kW from the final result you will get the total heating requirement for your house. It's then just a case of dividing this between the various rooms say according to room volume. As the upstairs rooms tend to be cooler than downstairs you could allow 45% of the heat upstairs and 55% downstairs.

If you want to do the job properly, do a google for "Stelrad Stars", which is a program you can download and install on your computer. You can then use it to work out what you need in each room. The rad total should be very close to that provided by the "whole house" calculator.

 

[helpsy]

Saw a guide that said room length x width x height(volume) x153 =btu rating.
Don't know if this is correct?
I'm sure someone will put me straight!!

 

[Plumbstar Tom]

That formula was around in the 1960's when central heating was becoming popular. Gas was cheap (state controlled) and The Gas Board, who had a monopoly, would advertise "guaranteed temperatures"; which was possible because they oversized the rads and the boiler. The formula makes no allowance for improvement in house design and insulation.

It is a quick fix idea for a DIYer, hence my statement of it for being for a DIYer, its not usually way out and it does only take into consideration the siza of a room. I use my trusty mears calculator, good old hand-me-down. Worth about £50 I'm told

Saw a guide that said room length x width x height(volume) x153 =btu rating.
Don't know if this is correct?
I'm sure someone will put me straight!!

Depends on the units you use to measure the room in?

 

[dontknowitall]

I use length x width x height in metres. Then multiply by: 40 for well insulated room with one outside wall, 45 for "normal room" or 50 for cold, poorly insulated 3 outside walls, large windows (e.g. conservatory or french doors). Then divide by 1000 and you have the wattage.

Never failed me yet.