K21 or K22 radiators

[b21playa]

Hi all

Need to replace some old radiators that have no convectors as the house is extremely cold, having the heating on all day doesn't get it past 15 degrees.

I have worked out the btu requirements for my bedroom which is around 10,000BTU. Currently there is a single panel radiator 600mm high x 2500mm long. Would I be better getting a shorter K22 or a longer K21 with approx same btu output?

I think I'll have to replace them all as none have convectors and although touching the radiator it can be hot, the room is far from warm.

Many thanks

 

[aptsys]

It's up to you. Whatever works in terms of available wall space if you know what your output requirements are.

Is your boiler up to the job?

 

[b21playa]

It's up to you. Whatever works in terms of available wall space if you know what your output requirements are.

Is your boiler up to the job?

Currently have a Potterton Kingfisher 2 cf100 but changing to a Vaillant ecotec plus 438 - think both are 100,000 BTU+

 

[fixitflav]

Hi all

Need to replace some old radiators that have no convectors as the house is extremely cold, having the heating on all day doesn't get it past 15 degrees.

I have worked out the btu requirements for my bedroom which is around 10,000BTU. Currently there is a single panel radiator 600mm high x 2500mm long. Would I be better getting a shorter K22 or a longer K21 with approx same btu output?

I think I'll have to replace them all as none have convectors and although touching the radiator it can be hot, the room is far from warm.

Many thanks[/QUOTE/

Do the rads get hot? If not, there's a problem elsewhere

 

[b21playa]

Yes the rads all get hot, just the room doesn't

 

[fixitflav]

Yes the rads all get hot, just the room doesn't

Maybe your calculated 10000 BTU/h isn't enough for some reason e.g. poor insulation. What are the theoretical outputs of the existing rad, and the alternatives you're considering? Perhaps you need to go bigger.

 

[b21playa]

Maybe your calculated 10000 BTU/h isn't enough for some reason e.g. poor insulation. What are the theoretical outputs of the existing rad, and the alternatives you're considering? Perhaps you need to go bigger.

The current rad in the room is nowhere near 10k BTU, its a single panel 600mm x 2500mm - I estimate around 5k BTU max

 

[fixitflav]

The current rad in the room is nowhere near 10k BTU, its a single panel 600mm x 2500mm - I estimate around 5k BTU max

OK that's your answer! Without going into it, I don't know the difference between the K21 and the K22, but if the output is something like your 10k BTU/h that should take care of it. 100k BTU/h boiler is more than adequate.

 

[b21playa]

How much difference does having convectors actually make over solid panel radiators?

 

[ReganAndCarter]

If you have the wall space, longer single panel will give better spread of heat. Double panels are more often specified where high outputs are needed but there is a lack of wall space. Do your sums carefully and oversize the new rad by 15 to 20 % of required heat output. Fitting a thermostatic rad valve will give you control so the room won't be too hot if a little over sized. If you're going for a new condensing boiler it will run more economically with larger rads anyway, and the bonus is quicker heat up of your house.

 

[b21playa]

If you have the wall space, longer single panel will give better spread of heat. Double panels are more often specified where high outputs are needed but there is a lack of wall space. Do your sums carefully and oversize the new rad by 15 to 20 % of required heat output. Fitting a thermostatic rad valve will give you control so the room won't be too hot if a little over sized. If you're going for a new condensing boiler it will run more economically with larger rads anyway, and the bonus is quicker heat up of your house.

Many thanks.

All the rads need changing really and valves are all jammed but going to try one in the bedroom as it’s freezing in there an another in the lounge as it’s falling off the wall and there’s no drain on that section of the pipework, as it’s at the lowest point. If this helps heat the house, i’ll go around changing them all.