What works out cheaper - heating immersion heater with gas or electricity?

[Mynydd]

I am trying to figure out if it is more energy friendly to let the hotpress run on electricity or on gas (set up such a way that it heats immersion heater only).
Our house is not fitted with an electric shower, so we use the hot press currently. I am more used to using gas for shower purposes (oh, where is the luxury of a combi boiler!) so maybe I should test it out myself with the gas meter, but maybe someone here has an idea what works out cheaper.

We have a very energy friendly condensed boiler but we keep it in a shed in the garden. (so longish travel time to the hot press). We are on standard rate tariffs for both ESB and Bord Gais.

Thanks!

 

[foamcutter]

Using the calculator on the SEI site [broken link removed]
It would seem that Natural Gas, as a source of fuel/energy is 4 times cheaper than electricity but it could depend on how your system is controlled.

 

[serotoninsid]

Gas by a long way.

 

[ClubMan]

Would ESB Nightsaver night rate compete with gas if that was an option?