Type 22 vs Type 21 radiators

[JohnW2]

I undertook some comparisons of Type 21 and Type 22 radiators, and it seems that with most makes and most suppliers, for a given height and heat output the price of Type 21 and 22 ones is much the same, the difference being that (due to less fins) the Type 21 are generally about 200 mm wider (for a given height and heat output).

That being the cases, is there ever any reason for favouring Type 21s ?>

Kind Regards, John

 

[aveatry]

I undertook some comparisons of Type 21 and Type 22 radiators, and it seems that with most makes and most suppliers, for a given height and heat output the price of Type 21 and 22 ones is much the same, the difference being that (due to less fins) the Type 21 are generally about 200 mm wider (for a given height and heat output).

That being the cases, is there ever any reason for favouring Type 21s ?>

Kind Regards, John

Yes I had this scenario and opted fro the type 21 because it did not stick out so far.

 

[JohnW2]

Yes I had this scenario and opted fro the type 21 because it did not stick out so far.

Ah, right, I didn't realise that, although I suppose I should have realised that such would be the case! Roughly how much deeper are the 22s?

 

[aveatry]

Ah, right, I didn't realise that, although I suppose I should have realised that such would be the case! Roughly how much deeper are the 22s?

Not a massive difference but it was enough of a difference for me especially due to the position the rad was fitted - also I was swapping an old one for another and did not want to alter the vale positions which have different centres on 21 and 22.
I think different manufactures have different code like p1 and p1+ p2+ indicating 1 panel plus fins ect

 

[JohnW2]

Not a massive difference but it was enough of a difference especially due to the position the rad was fitted - also I was swapping an old one for another and did not want to alter the vale positions which have different centres on 21 and 22.

Yes, I've just had a look at one make, and the 21's are 67mm deep, whilst the 22's are 100mm deep - so, although 50% deeper, that's only a difference of 33mm.

Kind Regards, John

 

[318Mike]

I fitted 21s simply because the rear panel guides the heat upwards and not at the wall.
They also appear neater and allow free passage between the wall and the back panel should I wish to hang something over.

 

[Madrab]

That being the cases, is there ever any reason for favouring Type 21s ?>

With rads it all really comes down to correct sizing to cover the space's heat loss and then the rest is just down to aesthetics.

 

[JohnW2]

I fitted 21s simply because the rear panel guides the heat upwards and not at the wall.

Are you talking aboy Type 21 vs Type 22 - which is the topic (and title!) of this discussion?
If so, I don't really understand your comment. In either case what is facing the wall is the essentially 'flat' face of the radiator, and it's primarily the fins (not usually seen if there is a 'cover' on the top of the rad) which "guide the heat upwards" - see post #44

They also appear neater and allow free passage between the wall and the back panel should I wish to hang something over.

Again, no difference between Type 21 and Type 22 other than that the latter 'sticks out' slightly further. ... and, in passing, "hanging something on" a rad is a good way of seriously reducing its effectiveness

 

[Madrab]

The fundamental difference between 21's and 22's is output. The greater depth, as mentioned, is to accomodate 2 sets of fins rather than 1. With 2 sets of fins the functional output of a given size of rad is greater in relation to the depth that the rad will sit from the wall.

Again though it all simply comes down to the output that the emitters need to provide to offset the heat loss that the space they are in encounters, once that's catered for it then simply comes down to aesthetics.

 

[JohnW2]

The fundamental difference between 21's and 22's is output. The greater depth, as mentioned, is to accomodate 2 sets of fins rather than 1. With 2 sets of fins the functional output of a given size of rad is greater in relation to the depth that the rad will sit from the wall. ... Again though it all simply comes down to the output that the emitters need to provide to offset the heat loss that the space they are in encounters, once that's catered for it then simply comes down to aesthetics.

That's all very true, but I suspect that most people's view of the aesthetics would be "as small and unobtrusive as possible", hence obviously favouring the 22s (over 21s)..

For that reason, I'm a little surprised that we don't see very much use of Type 33s (but 'renewable energy'may possibly change that ). Some people might not like them 'sticking out even more' (than 22s), but I suspect that much of the reason we don't see a lot more 33s is down to a 'vicious circle', whereby the fact that they are not (yet) used a lot makes them very expensive!

 

[Madrab]

That's all very true, but I suspect that most people's view of the aesthetics would be "as small and unobtrusive as possible", hence obviously favouring the 22s (over 21s)..

Maybe - but in my experience when it comes to a difference of ~ 30mm between them then there isn't that much difference in aesthetics - if client want a closer to the wall profile then I configure the brackets so the rad is on the short side rather than the long side.

Being on the longer side though makes the rad a little more efficient, as it creates more space for the air to circulate up and out past the back of the rad. Whether it's a K1 (21) or K2(22) for me as an installer is primarily down to output for a given size rather than it's depth, unless that's an absolute critical requirement of the clients

 

[318Mike]

My post above refers to the subject and how I applied it to my situation as a DIYer.
Aesthetics were not a consideration. All the replacement radiators we looked at were perfectly acceptable.
Following advice on here I increased the output (in BTU's) of my old radiators by 25% with type 22 110mm in the diner, 160mm in the lounge and type 21 everywhere else, all with TRVs and drain off taps.
(all witcompression connections).

The result was simply amazing!
Comparing new to old, the replacements got hot much quicker and heated each room up at least 50% faster, and all from an ancient Baxi backboiler!

 

[gas112]

. Whether it's a K1 (21) or K2(22) for me as an installer is primarily down to output for a given size rather than it's depth, unless that's an absolute critical requirement of the clients

K1 is single panel rad with fins not a 21 double . P+ is a 21

 

[JohnW2]

My post above refers to the subject and how I applied it to my situation as a DIYer.

Fair enough, but I still don't understand the comments you made about the back panels of the radiators.

Following advice on here I increased the output (in BTU's) of my old radiators by 25% with type 22 110mm in the diner, 160mm in the lounge and type 21 everywhere else, all with TRVs and drain off taps.

What do the "110mm" and "160mm"refer to?

The result was simply amazing! Comparing new to old, the replacements got hot much quicker and heated each room up at least 50% faster, and all from an ancient Baxi backboiler!

The increased output (due to a second set of fins) obviously should have resulted in the rooms being heated more rapidly, but I would not have expected the rads themselves to heat up any more rapidly.

 

[gas112]

The increased output (due to a second set of fins) obviously should have resulted in the rooms being heated more rapidly, but I would not have expected the rads themselves to heat up any more rapidly.

New rads are thinner metal than old rads so heat transfer is quicker