"Roly" wrote in message
...

Presumably all this heat could be used for something useful like hot
water or a swimming pool instead of going to waste ?

Its pretty low grade.
but you could use it to preheat the water in a ho****er system, or a pool.
If you want to be green you can put it into a ground storage system and
extract it later when the weathers gone cold.
All of which cost money.