Sizing radiators for condensing / non-condensing boilers

I think when radiators are sized for a central heating system, the size of rads required for each room would differ depending upon whether the system had a condensing or non-condensing boiler.

I'm not sure if the radiators should have greater output capability if its a condensing or non-condensing boiler? Would be interesting to know.

Whichever boiler type requires rads of greater output capability, I presume it would be possible to use the larger output rads irrespective of which boiler type is used?

If so, presumably its an idea to install the larger output rads, in case the boiler is changed from one boiler type to the other?

Thanks.

For a boiler to operate in full condensing mode the water returning to the boiler from the radiators has to be below 55°C.

The two important factors in determining the size of the radiators are

[1] the difference between the required room temperature and the mean temperature of the water in the radiator
[2] the mean temperature of the water in the radiator is the mid point between the water entering the radiator and the temperature of the water leaving the radiator.

Very often the radiators are quoted as having a certain heat output but without a clear indication of the mean water temperature necessary to achieve that heat output into the room.

Some explanation can be found HERE

Thanks Bernard.