Heat Efficiency: Column Radiators vs Double Panel Radiators?

paperclap

Hi all,

We are replacing our central heating system. We had initially planned to install Stelrad Homeline rads (type 21).

But, we've always loved the look of column radiators. We've found Milano Windsor column radiators to be good value, look great (though not seen them in person). Granted, they are double the price in comparison to type 21 rads.

I know the heat output between radiators effectively boils down to the BTU rating.

For example, a type 21 rad with a 3,500 BTU rating compared to a double column rad with a 3,500 BTU rating... should be the same, right? Or, is that not the case when it comes to "feeling" the heat? I've a feeling a type 21 rad would "feel" warmer, due to the fins. But, I'm not sure!

Which brings me to another question. Is it worth getting the triple or four column radiators? Or, do double column radiators typically suffice?

Can standard TRVs fit into column radiators?

Thank you.

Ajmason42

We have a very narrow column rad in our kitchen due to no wall space it does get warm but in my opinion no way as efficient as the standard rad as the gave the fins etc to help convection. Just replaced our lounge and dining room rads with stellrad double and a single and so far really really pleased with them. 

NSG666

Watch out with designer radiators they often use a different delta that inflates the heat output figures. As long as you are using the same delta then the heat outputs can be compared but the designer rads tend to be physically bigger and hold more water than a panel radiator Also, as I think was mentioned on one of your other threads, they sometimes need the flow and return connecting in a certain way so you need to know what your existing pipes are and look for the markings on the radiator.

You can use a regular TRVs on designer rads but I'd recommend using loctite pipecord rather than PTFE tape when fitting the tails - they are absolute pigs to drain if you get a small leak so adopt a belt and braces policy.

Bendy_House

Hi LWM.

As you suspect, heat output = heat output. They should both heat up the room to a very similar level.

There will likely be small differences between how they issue this heat, right enough, as there are two main ways in which a rad heats a room, radiation and convection. It could well be the case that a panel rad will 'feel' warmer when you sit close to it as there's a larger surface area adjacent to you where you'll feel radiated heat. But column rads also get 'hot' and will also radiate warmth.

The main method of warming the room is via convection, where the rad heats the air that flows naturally over it and which then circulates around the room via the ceiling.

We used two 'designed' column rads in our 6m x 6m extension (so current insulation standards), each one is only around 450mm wide x 1850mm high, with two sets of oval columns. It heats the room very effectively.

What I would suggest - regardless of the type you end up going for - is that you calculate pretty accurately the heat requirements of your rooms, and then go 'oversized' on your rads. Two reasons - one is that you'll have reserve there if it's needed during really cold spells (just crank up the boiler...) but the other - probably more important reason - is that you will be 'future-proofing' your installation, meaning you'll be able to run the boiler cooler (and more efficiently) when full output is not required, but also your rads will be more suited to future alternative heat sources such as air/ground-pumps which tend to produce lower output temps.

'Larger' rads will get the same overall heat into the room from a cooler water source, as 'standard' rads will do from a 'hot' source.

plumb1_2

NSG666 said:

You can use a regular TRVs on designer rads but I'd recommend using loctite pipecord rather than PTFE tape when fitting the tails - they are absolute pigs to drain if you get a small leak so adopt a belt and braces policy.

Ya best way to go, always use pipe cord, ptfe is no good for those type of rads.

FreeBear

Bendy_House said: What I would suggest - regardless of the type you end up going for - is that you calculate pretty accurately the heat requirements of your rooms, and then go 'oversized' on your rads. Two reasons -... but the other - probably more important reason - is that you will be 'future-proofing' your installation, meaning you'll be able to run the boiler cooler (and more efficiently) when full output is not required, but also your rads will be more suited to future alternative heat sources such as air/ground-pumps which tend to produce lower output temps.

Alternative heating such as ground/air heat source pumps produce relatively low water temperatures - To make most of heat pumps, your radiators need to be bigger by 50% or more. Not always a practical proposition.

paperclap

Thanks all.

Though, I think there has been a little confusion (or maybe, I’m confused!). We are interested in column rads, not designer rads. The two are quite different, aren’t they?

Could PTFE tape not be used on columns rads? As no doubt they have the same 15mm inlet.

I am actually struggling to find an accurate or consistent BTU reading on some of the online calculators. Some work to a Delta 40 rating, whereas others work to Delta 65. Some include the recommended additional 10% BTU, others don’t. Very frustrating!

I’ve mainly been using BestHeating’s calculator, but I think I read somewhere that it uses Delta 65. Ideally, I’d want a calculator using Delta 40, wouldn’t I?

Bendy_House

laurencewhymark said:

Though, I think there has been a little confusion (or maybe, I’m confused!). We are interested in column rads, not designer rads. The two are quite different, aren’t they?

I think it would be fair to say that 'column' rads are 'designer' rads. No-one would choose column rads for 'maximising heat output for the rad size' ability, but instead do so for 'design' reasons (and I don't blame them - they look great).

A quick glance at the screwfix site suggests that column rads would need to be around 40% physically larger to achieve the same output as a type 22 panel rad. You obviously need to be certain that you calculate that in - which I know you are.

Ultimately, heat output = heat output, regardless of rad type.

Sorry, don't know what to recommend re 'deltas', but would urge you again to go 'large' if you possibly can.

koalakoala

I have eleven radiators in my house and the only one which causes problems is the one column, chosen due to lack of space where I wanted it.

Bendy_House

koalakoala said:

I have eleven radiators in my house and the only one which causes problems is the one column, chosen due to lack of space where I wanted it.

Is this a 'tall' column rad? What's the issue - trapped wind? barp...

Another_Level

Doubt anyone has actually worked out the efficiency comparing column type radiators to convector radiators.

As already mentioned columns with large surface areas radiate out a lot of heat, sometimes mistaken for it being efficient.

Vertical Panel radiators with convector fins are available ie stelrad vita and others.