On Sep 7, 7:20*pm, Dave wrote:
What is the efficiency difference between a 1970's double radiator to
today's double rads fitted with fins?

Reminds me of the nonsense marketing by the electric radiator sellers,
Calortec and a whole host of others. The saving grace of Calortec was
the aluminium radiator extrusions were well made, well finished, and
little more than the cost of buying the actual extrusions separately
and bolting them together (as in £90 v £120 for example). Those priced
at £280-480 are just a ripoff. The disadvantage of Calortec I suspect
will be parts availability since Argos/Homebase have discontinued them
and thus "repair" will be a case of "refund".

If you want to reduce cost, insulate the main living area, get rid of
draughts.