The State-owned company, which has 1.1 million customers, has bucked the trend after three energy suppliers announced price rises this year.
The move comes as hundreds of thousands of families will struggle to pay energy bills in the coming months.
Already 300,000 households are in arrears on electricity bills, and the Government has insisted it is not paying energy credits in next month’s Budget.
Electric Ireland said its residential gas prices will decrease by 4pc from November 1.
Standing charges for gas are also going down by 4pc.
Its residential electricity prices will remain unchanged for its more than a million residential customers.
Electric Ireland said it remains committed to providing ongoing value to its customers.
The gas cut equates to a €58 saving a year on the average gas bill, the ESB-owned company said.
Electric Ireland said this means its gas standard variable tariff will be one of the most competitive on the market.
Consumers are facing higher energy bills in the coming months. Stock image
Today’s News in 90 Seconds, Wednesday, September 10
The move has upended the market with expectations that it would join Energia, SSE Airtricity and Flogas in announcing a price hike.
Those three companies have a combined customer base of around 600,000.
Electric Ireland said the cut was the fourth consecutive decrease for residential gas customers since November 2023
This means has led to a cumulative reduction of 23.6pc, and savings of €390 (excluding VAT and carbon tax) on the average annual gas bill.
Residential electricity unit rates and standing charges will remain unchanged.
Since November 2023, Electric Ireland has reduced residential electricity unit rates three times.
It said this has delivered a cumulative reduction of up to 19.34pc, and savings of up to €376 (excluding VAT and PSO levy) per annum.
Executive director at Electric Ireland Pat Fenlon said: “We are acutely conscious of the financial pressures facing our customers and we believe today’s announcement will provide improved value for Electric Ireland customers as we face into the winter.”
The Electric Ireland move raises questions about the justification for Energia’s announcement on Monday to hike its electricity costs by up to 12pc, and its standing charge by the same percentage.
The move will cost families €200 a year.
From October 9, Energia electricity customers will be hit with a 10.9pc increase.
This will work out at a rise of €205 a year on the average bill.
Energia Dual Fuel customers are to have a 6pc increase imposed on them.
Last month some 45,500 Flogas residential electricity customers were hit by a price rise of around €10.51 a month, adding €126 to annual bills.
It blamed higher network charges after it announced a rise of 7pc in electricity prices.
In April, SSE Airtricity raised electricity bills by 10.5pc, and gas bills by 8.4pc.
The move impacted around 250,000 electricity customers and 85,000 gas customers.
It blamed rising wholesale energy prices and higher network charges imposed by the energy regulator.
Daragh Cassidy of price comparison site Bonkers.ie said the Electric Ireland move was good news, but a bit of a surprise.
“Electric Ireland is the country’s biggest energy supplier so many customers will no doubt be relieved to know that their electricity prices aren’t going to increase for the next few months and that their gas bills are actually going to fall.”
But he said energy prices still remain high.
And some of the gas savings are going to be taken back by the Government next month when it increases the rate of carbon tax in the Budget again.