It's a challening question to answer, because there are so many variables.
As a starting point, look at the different unit rates between gas and electricity from your current supplier.
See how many gas units you used.
Now calculate the same unit usage based on the electricity unit rate.
These are the Bord Gais unit prices:
https://www.bordgaisenergy.ie/publications/tariffs/
How many rooms will you need to heat? Living room, 2 x bedrooms, bathroom?
Is the electric heating night storage based i.e. do your heaters only draw in energy during the night and release it during the day - usually these are charged at 1/2 the rate of normal usage.
Are you buying or renting i.e. will you have scope to put in newer energy efficient heaters? new windows?
I have first generation night storage heaters, I think I did some calculations and it was working out at €2 per night for living room (max setting) and €1 per night for a bedroom (medium setting).
See thread here on discounts available from different energy companies... make sure you are getting some sort of discount on your plan:
https://www.askaboutmoney.com/threa...upplier-which-rewards-loyal-customers.203843/
And external link:
http://www.*****************.com/electricity-and-gas-cheapest-combined-prices.html