Radiator sizing software?

[Harnser]

After this cold spell I'm trying to work out what size radiators I need in this house as I think the current ones are undersized.

I've been using https://app.starsapp.co.uk/ from Steelrad but it's clunky and slow to use.
And it gives 2 heat loss figures for each room that are a factor of 2 out from each other.

Is there something better that the pros use? I am willing to pay for software that makes my life easier.

 

[robj20]

99% of pros don't do it correctly.
Just do the baths yourself but don't use the default delta 50t aim for 30t.
Or just fit the biggest rads you can in each area, with modern thermostats and boilers there really isn't a downside to fitting huge radiators only the visual downside.

Radiator Calculator

Get the right sized radiator for your room. Our calculator with provide heat output recommendations in BTU and Watts.

www.homesupply.co.uk

 

[Deleted User 298457]

It really isn't that complicated. Just do it methodically.

BTU Calculator | Measure Radiator Heat Output | UK Radiators

Use our online calculator to determine your BTU requirements. BTU stands for British Thermal Unit and is the measurement of energy for heating systems.

ukradiators.com

 

[Bazzards]

Not very scientific I know, But I just purchased the largest rads that would fit under the windows. These were double the size of the existing rads in most rooms.

My rooms aren’t particularly large though, so probably best to use the btu calculator.

 

[jpaul]

I'd be doing the calculation based on expected U values .. for the era of house you have (earlier post) which can be 3x worse on an 80's property versus 2010's
then https://www.diydata.com/planning/ch_design/example1_imperial.php

if you just fit large radiators probably have to check the piping/pump is up to it - place I'm in just has microbore;
otherwise would be like running a 3KW electric fire off of a puny extension lead?

 

[Harnser]

I'd be doing the calculation based on expected U values .. for the era of house you have (earlier post) which can be 3x worse on an 80's property versus 2010's
then https://www.diydata.com/planning/ch_design/example1_imperial.php

The Steelrad calculator is good like that; you have to select the materials for each wall, type of door etc:

Edit: The ceiling choices miss an option for downstairs room with heated room above.

I have had to guess the type as the house is rendered. The 1920s part has cinder block inside, the extension some kind of cavity fill so assuming this one above is right for the new part.

 

[R.O.S.S.I]

Sorry to hijack thread but i've been wondering how you would factor in UFH into calculations regarding what amount of rads your boiler will be able to power?

We only have 4 single panel rads upstairs and one towel radiator but the downstairs is UFH. I had been wondering if we could replace rads with double panel without causing any issues with the boiler or not?

 

[SpellowHouse]

Most people who think their radiators are too small, it usually turns out that their boiler is a newish on-demand boiler that is simply too powerful. It heats the water up so fast that its only on for a few minutes and it switches off again. May be you need a modulating boiler.