Bord Gáis Energy is to increase household energy prices from next month.
This will see a typical gas bill go up by €8.16 per month, while electricity will increase by €10.26 from October 24th.
The company says this is "due to the all-time high cost of energy".
It says global energy costs - and particularly gas costs - have hit all-time highs due to a combination of restricted supply levels, higher carbon prices and market volatility.
But it says it will guarantee customers will not face any further price increases before the spring of 2022.
"While the current price highs and volatility are expected to remain for some time, Bord Gáis Energy has confirmed it will pass on any savings and reductions to customers wherever and whenever it can", it adds.
- The changes include:
12% increase in gas unit rate and standing charge - which equates to 10.98% increase on the average bill
- 10% increase in electricity unit rate and standing charge - around a 9.54% increase on the average bill
These figures are based on a typical annual consumption of 4,200 kWh for electricity and 11,000 kWh for gas.
The gas price change is its second increase in two years.
Dave Kirwan, managing director at Bord Gáis Energy, says: "We are experiencing an extremely uncertain energy market right now and we know our customers are concerned about that.
"We regret that we have to pass through a price increase at this time, but we have taken steps to protect our customers against further movement during the colder winter months ahead.
"Today we confirmed a unique guarantee to hold these prices until spring 2022."
It comes amid calls for maximum price orders to prevent 'simply unaffordable' energy prices this winter.
Tánaiste Leo Varadkar has warned energy companies could go out of business as a result.
But People Before Profit TD Paul Murphy has told Newstalk Breakfast he believes price caps are justified.
"People are faced with huge energy price rises this winter - already prices are gone up by, in some cases, 25%.
"That's going to amount to a total increase in costs for many people of €400, €500 over the course of the winter.
"And in a context when one in 10 of the population lives with fuel poverty, which means that they struggle to pay their bills... that extra cost is simply unaffordable.
"So as an immediate first step, yes maximum price orders to say 'This is the maximum cost that a company can charge per unit'", he says.