Radiators - where and size?

Deedoodee

FreeBear said:

A word of warning with type 22 (and even more so with type 33) - They stick out a long way from the wall, so if you were hoping for a slim fit, you will be disappointed. 

Just measured the protrusion. Type 21 might be the way to go…

Deedoodee

Is there a simple way of getting the output of the other radiator? Can’t find any identifying labels on it. 

Used another BTU calculator and answers range between 7,000 and 9,000 for the whole room. So I think if I get one around 8,000. That would be about 1.5 oversized using conservative values.

9,000/2 = 4,500
4,500/ 0.515 = 8737

so the largest 8181BTU, which is 1.8m wide… which would fit but not ideal. 

Is that a good idea or over kill considering none of the other radiators are oversized (assuming they’re not)? 

There’s one at 6363 BTU (at 50) which is half the price and a much better size. But will that be enough?

FreeBear

Deedoodee said:

Is there a simple way of getting the output of the other radiator? Can’t find any identifying labels on it. 

Used another BTU calculator and answers range between 7,000 and 9,000 for the whole room. So I think if I get one around 8,000. That would be about 1.5 oversized using conservative values.

9,000/2 = 4,500
4,500/ 0.515 = 8737

so the largest 8181BTU, which is 1.8m wide… which would fit but not ideal. 

Is that a good idea or over kill considering none of the other radiators are oversized (assuming they’re not)? 

There’s one at 6363 BTU (at 50) which is half the price and a much better size. But will that be enough?

Measure the height/width of the radiator, then look up the dimensions in that Kudox pdf. The numbers will be similar regardless of manufacturer for most domestic radiators (designer & custom rads, a different matter).

Not sure where you are going with your calculations, but if the BTU calc is saying ~8,000BTU at ∆T50, then you'd need a 16,000BTU rad at ∆T30 (or multiple radiators to give the same output).

Deedoodee

FreeBear said:

Deedoodee said:

Is there a simple way of getting the output of the other radiator? Can’t find any identifying labels on it. 

Used another BTU calculator and answers range between 7,000 and 9,000 for the whole room. So I think if I get one around 8,000. That would be about 1.5 oversized using conservative values.

9,000/2 = 4,500
4,500/ 0.515 = 8737

so the largest 8181BTU, which is 1.8m wide… which would fit but not ideal. 

Is that a good idea or over kill considering none of the other radiators are oversized (assuming they’re not)? 

There’s one at 6363 BTU (at 50) which is half the price and a much better size. But will that be enough?

Measure the height/width of the radiator, then look up the dimensions in that Kudox pdf. The numbers will be similar regardless of manufacturer for most domestic radiators (designer & custom rads, a different matter).

Not sure where you are going with your calculations, but if the BTU calc is saying ~8,000BTU at ∆T50, then you'd need a 16,000BTU rad at ∆T30 (or multiple radiators to give the same output).

The room has two radiators. I don’t know what the output of the other one is. 

I’m working off the assumption at if required, I’ll replace the existing one with a similar one to the new one. 

Values are for just the single new rad. 

So 8,000 for the room so ~16,000 for delta 30 for the room.  

But there are two radiators, so just under 8,000 for each. 

I think my question was badly worded, if I’m not going to be able to run the radiator at a much lower temp (because of the existing ones), would it be overkill to size to delta 30? Especially given the extra size that would be required (1.8m radiator or 135mm protrusion). Would it be more sensible to get the new one with output of 7,000 or even 6,000BTU? 

BUFF

Deedoodee said:

The vendor put on the PIF that it’s from 2019 (though it’s come to light that they incorrectly filled in/ lied in other parts of the PIF… ). Both the plumber and electrician have said ‘oh this is a new one!’ when they saw the boiler so I assume it’s relatively new

Does it have a label on it with make/model? 
Whilst we are at it what sort of controls (programmer/room stat/TRVs?) do you have? Controls really can make a difference to energy consumption if used properly.

BUFF

Deedoodee said:

I think my question was badly worded, if I’m not going to be able to run the radiator at a much lower temp (because of the existing ones), would it be overkill to size to delta 30? Especially given the extra size that would be required (1.8m radiator or 135mm protrusion). Would it be more sensible to get the new one with output of 7,000 or even 6,000BTU? 

Not if you need/want to change the rad now &  intend to eventually change all the radiators over time & run from a heatpump in the future. You are just staggering your upgrades rather than doing it all at once in the future.

p.s. I have mostly K2/Type 22 rads in my house & I don't find them overly intrusive - typically ~125mm deep v ~100mm for a 21.

Deedoodee

BUFF said:

Deedoodee said:

The vendor put on the PIF that it’s from 2019 (though it’s come to light that they incorrectly filled in/ lied in other parts of the PIF… ). Both the plumber and electrician have said ‘oh this is a new one!’ when they saw the boiler so I assume it’s relatively new

Does it have a label on it with make/model? 
Whilst we are at it what sort of controls (programmer/room stat/TRVs?) do you have? Controls really can make a difference to energy consumption if used properly.

All the downstairs ones are ‘designer’. The vertical ones have crosshead valves at the base. They don’t look like TRVs I know. Not sure about the other living room one. Can’t see a label either. Will have to lift it up and check again. I tried Googling but wasn’t useful 

Deedoodee

BUFF said:

Deedoodee said:

I think my question was badly worded, if I’m not going to be able to run the radiator at a much lower temp (because of the existing ones), would it be overkill to size to delta 30? Especially given the extra size that would be required (1.8m radiator or 135mm protrusion). Would it be more sensible to get the new one with output of 7,000 or even 6,000BTU? 

Not if you need/want to change the rad now &  intend to eventually change all the radiators over time & run from a heatpump in the future. You are just staggering your upgrades rather than doing it all at once in the future.

p.s. I have mostly K2/Type 22 rads in my house & I don't find them overly intrusive - typically ~125mm deep v ~100mm for a 21.

I don’t envisage getting a heat pump anytime soon. We’re more likely to move before putting that kind of investment into this house. it was more for being able to run the boiler at a lower temperature, seeing as we’re replacing one of the radiators anyway.

Bendy_House

I put a wee spanner in your works, Deedoo

The ideal form of room heating from an ASHP is probably Under-Floor, as that works using only low flow temps. But that's a bigger cost again.

I don't want to overstate the case for oversizing rads, and I'm just not that clued up with the whole malarkey. BUT, I just know that, with condensing boilers (which yours will certainly be, from what you said about its age), the cooler you run it, the more efficient it will be.

This is because the return flow - from the rads - is used to cool the burnt flue gases, condense out the water vapour that has been produced, and therefore extract the heat from that process. If you stick your hand in the flue gases of a condie boiler compared to a non-condie, you'd certainly notice the difference, and with the latter, that heat is going straight outside.

The ideal way to run a condie boiler, is to keep turning down the flow temp control until it does its job of heating your home, and no more. Ie, as winter approaches, you'd have to keep tweaking it up. (You can get 'weather compensators' that'll do that job automatically.) Obviously, if you turn it down too low, your standard rads won't give out enough heat. The answer to that is to fit larger rads, or more of them. But, yes, they are big an ugly.

Is this worth doing for the whole house? No, because it'll cost many hundreds, and would take years to recoup.

Is it worth doing for one rad? Well, that largely depends where that rad is located. If it's in a bedroom, I'd say probably not. If it's in your main living area - the place that's (a) the warmest, and (b) heated for much longer, I'd suggest probably 'yes'.

With all the provisos you've mentioned before - eg, if you cool the boiler for this rad, all the other rads will be cooler too.

What to do? That's got to be your call. It's just that you have the ideal opportunity right now to start tweaking your CH 'better', and making it more energy efficient. I'm pretty sure I'd do this, but not to the extent that the new rad is a monstrosity.

Your designer rads are unfortunately not helping you, as they are likely to be the least-output for their size.

Deedoodee

Bendy_House said:

I put a wee spanner in your works, Deedoo

The ideal form of room heating from an ASHP is probably Under-Floor, as that works using only low flow temps. But that's a bigger cost again.

I don't want to overstate the case for oversizing rads, and I'm just not that clued up with the whole malarkey. BUT, I just know that, with condensing boilers (which yours will certainly be, from what you said about its age), the cooler you run it, the more efficient it will be.

This is because the return flow - from the rads - is used to cool the burnt flue gases, condense out the water vapour that has been produced, and therefore extract the heat from that process. If you stick your hand in the flue gases of a condie boiler compared to a non-condie, you'd certainly notice the difference, and with the latter, that heat is going straight outside.

The ideal way to run a condie boiler, is to keep turning down the flow temp control until it does its job of heating your home, and no more. Ie, as winter approaches, you'd have to keep tweaking it up. (You can get 'weather compensators' that'll do that job automatically.) Obviously, if you turn it down too low, your standard rads won't give out enough heat. The answer to that is to fit larger rads, or more of them. But, yes, they are big an ugly.

Is this worth doing for the whole house? No, because it'll cost many hundreds, and would take years to recoup.

Is it worth doing for one rad? Well, that largely depends where that rad is located. If it's in a bedroom, I'd say probably not. If it's in your main living area - the place that's (a) the warmest, and (b) heated for much longer, I'd suggest probably 'yes'.

With all the provisos you've mentioned before - eg, if you cool the boiler for this rad, all the other rads will be cooler too.

What to do? That's got to be your call. It's just that you have the ideal opportunity right now to start tweaking your CH 'better', and making it more energy efficient. I'm pretty sure I'd do this, but not to the extent that the new rad is a monstrosity.

Your designer rads are unfortunately not helping you, as they are likely to be the least-output for their size.

Thanks. This does make sense. 

The new replacement radiator will be in the living/ dining room, so the main room we’ll use when we’re at home in the evenings. we won’t use the offices/ spare bedrooms so much in the evenings. 

So it’s a balance of ugly large rad sizes against higher output. We’ll go and tape up the wall and see how much we can fit.

thanks everyone