"JoeJoe" wrote in message
...
I have a brand new combi running 18 radiators + 1 shower in my house. No
complaints there.

Problem is that the radiators seem to be getting very cold very quickly as
soon as the boiler is switched off.

Good. It means they are doing their job, i.e. radiating, very well.


My suspicion is that the cause could be
because some of the pipes (copper) hat feed the downstairs radiators are
not
insulated. I have a 1m high space under the house, where the pipes are
located, and it is freezing cold and drafty there.

Does it make sense?

No. 99% of the heat loss from the radiators will be to the room itself. Only
a tiny part will go back down the thin pipes to radiate under the floor.


Will it be a good idea to insulate the pipes?

Of course. You're losing heat to the underfloor space all the time the pipes
are hot while the boiler is on.
--
Dave Baker
Puma Race Engines
www.pumaracing.co.uk
Camp USA engineer minces about for high performance specialist (4,4,7)