It says the move will lead to significant savings for customers, with an average cost reduction of €100 per year.
Those with less than average consumption can expect to save €165, or 25%, over the course of a year.
The Commission has also reduced the annual standing charge from €308.58 to €56.75.
It says it hopes this will encourage greater efficiency because a larger proportion of customers' bills will relate directly to consumption levels.
It is the second time this year that gas prices have been reduced, a 10% reduction was applied on 1 February.
Today's announcement confirms the price cut that was proposed in July and the reduction in the annual charge that was put forward in June.
