On Fri, 07 Nov 2008 11:08:15 +0000, Andy Kirkland
wrote:

Hi,

I've got a hot water tank (approx 4' high) and it's currently got a tiny
immersion heater element (11" from what I can guess off the label and
also the pitiful amount of water that a single heating produces).

I would like to replace it to enable it to heat the majority/entire
tank. Is there any rule of thumb/limit on what length of heater you can
use versus the size/height of the tank?

Andy

Can't you just measure the depth of the tank and buy one to fit ,like
a 24 " one for example.
I'm assuming there is enough room above the tank to let you get a
longer one in .