Over 1 million energy customers will feel the impact of larger bills from today.
Electric Ireland and PrePayPower are increasing their gas and electricity prices by 4% and 3.9% respectively, having frozen them over the winter months.
The increase will add around €38 a year to the average Electric Ireland customer’s electricity bill and €30 a year to the average gas bill. Meanwhile PrePayPower customers will see their annual electricity and gas bills increase by around €50 and €35 respectively.
Electric Ireland has just over 1.1 million electricity customers and around 140,000 gas customers. PrePayPower has around 140,000 electricity customers and 40,000 gas customers.
Both suppliers, as well as most of the other energy suppliers increased their prices last year.
Daragh Cassidy, Head of Communications at price comparison and consumer website, Bonkers.ie, said the main reason for the increases is that the price of energy on international markets still remains high.
"We import a huge amount of our energy from abroad," he said. "We import gas, coal and oil, and unfortunately all of those fossil fuels are increasing in price and still remain very, very high on international markets. Unfortunately, this means that further price increase cannot be ruled out in the months ahead."
Mr Cassidy said renewable energy will not necessarily be cheaper. ESB is investing in wind energy but investment costs money.
"Renewable energy is greener, it is cleaner but it is not necessarily cheaper energy yet, so just because we are using more renewable energy doesn't mean that's going to lead to lower bills just yet."
Energy suppliers save their best prices for new customers, but asked if existing customers should contact their supplier and negotiate a better price, Mr Cassidy said it is worth the call.
"Obviously we would recommend that people switch, but there is a lot to be said for contacting your existing supplier as well, and seeing if you can negotiate a better deal. Sometimes we find that the retention offers that suppliers give, are not quite as good as the offer that they give new customers."
Customers could save over €400 annually on gas and electricity by switching.
Another way to lower energy bills is to consume less. Customers can do this by figuring out which appliances in their home use the most energy and then looking for ways to reduce their consumption.
"Installing LED lightbulbs, which use up to 90% less energy than a standard light bulb, will save customers money too", says Daragh.
Finally customers can look at ways to make their home more energy-efficient.
"For example putting in solar panels or installing attic or wall insulation. And the good news is that there are lots of grants available from the SEAI (Sustainable Energy Authority of Ireland) to help cut down on costs."