But without exaggeration, because oversizing can lead to the fact that in November in the apartment there will be a sauna, even if the radiators were not warmer than the girl's back. The RETURN temperature is important for condensation, not the flow, i.e. the RETURN temperature should not exceed 50 degrees to maintain condensation. In most installations, the return temperature of 50 degrees occurs when the supply is 70 degrees, and these are really hot radiators (they burn when touched) and temperatures of 20 degrees below zero are rare (or they do not occur in a given season, or it is one or two nights), and the most common period of the heating season, however, are outside temperatures above zero, i.e. when theoretical parameters are 70/50 (70 degrees power supply, 50 return), then for most of the season (e.g. outside temperature + 2 degrees) will usually be power - no more than 50 degrees, return -40 or less. So it is better not to overdo it with oversizing of radiators, the more that larger radiators are larger capacity and the boiler will heat this amount of water longer after switching on.
