Customers in greater Belfast will see prices fall by up to 10 per cent, while those in the ‘ten towns’ gas network outside Belfast will get a 5 per cent cut.
The firm said the reason for the decrease, which follows recent cuts of 10 per cent by rival energy firm SSE Airtricity, was the continuing fall in wholesale gas prices.
The Utility Regulator welcomed the cuts, saying consumers in Northern Ireland are “continuing to benefit from among the lowest gas standard tariffs in the UK”.
The ten towns and greater Belfast areas are two separate markets with different distribution network operators.
The regulator pointed out that the reduction of 5 per cent is less than the Airtricity reduction because of different network cost movements in the two gas areas, and Airtricity returning an over recovery from the previous tariff period to customers in the Belfast area.
A spokesperson for Firmus Energy told the BBC that natural gas costs only make up around 50 per cent of the bill, with the remainder made up of distribution and transmission costs.
“These costs are 21 per cent higher in the ten towns licence area than in greater Belfast and have been reviewed and approved by the Utility Regulator.
“We work closely with the Utility Regulator at all times and as always, we will continue to monitor all costs and wholesale fuel prices closely to ensure the price we pass on to our customers is the best value that we can offer.”