"PerryOne" wrote in message
...


Every time your boiler runs, it blows heat out the chimney and it has
to heat up the pipes and the radiators before you feel any warmth at
all.
Heating all this metal, water and air costs money.
Over the last few years, radiator manufactures have made radiators
with less metal, holding less water to be most economic.
Cast iron radiators got left behind as they absorb so much heat and
cost more to run.
Perry

Think about the physics of what you wrote. Where does that heat go once in
the radiators? How would they cost more to run? They may be less
responsive, but the thermal mass is a plus. If it goes into the water and
the metal, it is going to eventually come back out.