Can anyone help me understand the difference between two radiators?

[Wes Moore]

I'm looking to put an extra column radiator in my living room and when doing my research found one secondhand on Facebook marketplace that I figured could help me save some money on what can be expensive radiators. Anyway, the advert had a link to the sale page for the radiator:

https://www.NoLinkingToThis/p/acova...tu/46099#product_additional_details_container

Whilst looking I thought I'd take a look and see what other options are around and found this on B&Qs website:

SKY Bathroom White Radiator 2 Column Cast Iron 1800x380mmVertical Central Heating | DIY at B&Q

Our Radiator are made of a durable low carbon steel construction and a high quality powder coating, which is very durable and strong and has a long service life. And the appearance is beautiful, is an effortless fashion radiator, to adapt to a variety of styles of decoration.

www.diy.com

The first is £265, 2m x 40cm, 3700 BTU
The second is £165, 1.8m x 38, 5010 BTU

What I'm looking for help with is can someone explain the difference here? How is the cheaper, smaller one putting put out so much more heat? Or is BTU not the best value to compare on (like BMI for a person's health etc...). I'm a novice and don't know why I, or anyone, would buy the more expensive one. But there must be something I'm missing.

Thanks very much for your help

Wes

 

[exedon2]

Interesting spec for b&q one
At top claims to be 2 colum cast iron
Further down says its made of low carbon steel in specification says its stainless steel!
On that basis don't believe a word of it.

 

[Ben-gee]

Btu is a good value to use, provided it is accompanied by the deltaT value with which it is associated.

Your two rads in question : the first one is 3800btu at delta 50 - which is the same as 4800 btu at delta 60.

The second rad has no delta T given so its btu value is effectively meaningless.
However if it were delta 60 then you can see the two rads would have very similar real world output.

 

[Wes Moore]

Thanks so much for your responses. Always good to learn more.

Just briefly, I think the point made above that the multiple stated materials for the B&Q rad make it's whole spec unreliable. But in real world terms, what would the difference be between a cast iron, low carbon steel or stainless steel rad?