On 24/12/2016 10:07, DerbyBorn wrote:
Are immersion heaters as efficient as they could be? Could the tubular
element be improved upon - or doesn't it matter?



I suppose you could improve on the design to allow it to get the heat
away quicker - .... by having a load of fins - and therefore create
surface area in contact with the water.
Wouldn't make conversion of electricity to heat any more efficient.

Cost involved probably not worth any gain.