Pinergy has become latest energy supplier to increase its prices.
It has announced an 18% rise in the rate it charges for electricity from today.
This comes despite a fall in wholesale energy prices.
Energy Economist at the ESRI, Muireann Lynch said pre paid meter rates and fixed charge rate customers will not be affected.
"Pinergy are increasing their unit rate by about 18%, but they're not doing to their prepaid meter rates and they're not doing anything to their fixed charges.
"That means you're probably looking at a 14% increase in your bill, provided you don't change your usage at all."
