changing radiators

[rgregson1919]

Hello all


I want to replace 5 of the 10 radiators in the house with more efficient modern ones. The five are at least 25 years old (as that’s how long we have been in the house).


Can I just go for a similar physical size of type 21 or 22?


I know, I will probably have to adjust the pipework and am OK with that.


I read things about old designs being designed for higher flow temps and nowadays it is lower. Do I have to consider BTU calculations for each room?


Boiler is a 30KW condensing Vaillant and the house is a Victorian terrace (three bed + loft room).

 

[CBW]

I don’t really do much radiator sizing, but would say so. Are you end or mid terrace?

 

[rgregson1919]

I am mid terrace.

 

[CBW]

I am mid terrace.

Sounds ok with what you propose, but would go for similar, eg replace a single panel with single panel.

 

[rgregson1919]

many thanks, it will be a job in the summer for me. Just getting my research in early.

 

[oldbuffer]

1. The heat required to warm any room to the desired temperature, and maintain it at that temperature, is entirely determined by the difference in temperature between the inside and outside of each surface (wall, window, door, ceiling, floor) and the rate of heat transfer through the surface.
2. New radiators will be no more (or less) efficient than old ones. However, they may heat the room up more quickly.

 

[Madrab]

What radiators do you have just now? Are they just straight panel or do they have convector fins in them?

 

[rgregson1919]

They are just straight panel. Some of them are double panel. No fins. Two out of the ten are bathroom towel rails.

 

[rgregson1919]

so I guess if they heat up the room more quickly, they are more efficient which would be a good thing?

 

[oldbuffer]

1. Efficiency in relation to heating system is generally defined as the amount of heat given out divided by the amount of heat put in (as a percentage).
2. Modern radiators may heat up more quickly, but then they will also cool down more quickly. In consequence the total amount of heat they give out for a given volume of water though them is the same as for older radiators.

 

[Madrab]

Efficiency has 2 meanings to me when it comes to radiators. The normal everyday efficiency as the rated heat output of the panel.

The most important one in my book though is how efficient it is at heats the air in the room to maximise room warm up time. Type 22/K2's are obviously the most efficient watt for watt at heating the space, as they most efficient at heating the air that convects up through it.